MP3 Trigger v2

Replacement:WIG-11029. The new version of this board replaces the VLSI VS1053 with the VS1063, there are also several firmware changes and improvements. This page is for reference only.

Created in collaboration with Jamie Robertson, the MP3 Trigger is quite possibly the most versatile, low-cost, low power embedded MP3 Player. The board has 18 external trigger pins that will directly trigger pre-selected MP3 tracks, and a full-duplex serial control port that provides full transport control, remote triggering for up to 256 tracks, and fast real-time volume control. The board plays the MP3 files directly from a FAT16 microSD flash card and supports 192Kbps stereo playback. There is also an on-board navigation switch for local access and playback of all MP3 tracks on the flash card.

New for version 2: Aside from more than doubling the number of trigger inputs, the MP3 Trigger v2 now contains a resident bootloader that enables firmware updates directly from the microSD card without requiring a hardware programmer. The PSoC Designer IDE can be used to generate hex files for the bootloader. See the datasheet below for more details on how to use the bootloader.

Firmware version 2 also incorporates “Quiet Mode”, a new feature that can be enabled via the serial control port. In this mode, the triggers don’t start tracks directly, but instead produce a serial message indicating which triggers were activated. A host microcontroller (Arduino, for example) can thus monitor the trigger inputs and then start any track or sequence of tracks via the serial control port, making the triggers much more flexible.

The board uses a Cypress PSoC CY8C29466-24SXI microcontroller and a VLSI VS1053 audio codec.

Board can be powered by an external wall wart, FTDI Basic, or raw 3.3V input (see related items below).

Firmware update 2.40 Beta: Check it out here and be sure to leave feedback on the blog post.

Firmware update 2.23: compatible with 192kbps audio.

We use the most up-to-date firmware on everything we ship out. However, if you have an older v2.xx model (or want to change the baud rate) and wish to have the newest firmware, you can get it here.

Instructions on how to update your v2.xx firmware are in the datasheet, but here’s a quick review:

  1. Download and unzip one of the files above.
  2. Copy the resulting hex file to a microSD card and rename it to: “MP3TRIGR.HEX”. It does not need to be the only file on the card – it just needs to have that precise filename.
  3. Insert the microSD card into your MP3 Trigger V2 and turn the power on while holding down the center navigation switch.
  4. Wait for the Status LED to go solid, then cycle the power. You’re now running the new firmware.

    Please refer to the datasheet for a more detailed description of the Status LED indications when running the bootloader.

Note: This product is a collaboration with Jamie Robertson. A portion of each sales goes back to them for product support and continued development.

  • Input voltage: 4.5-12VDC
  • Current Consumption: 45mA idle, 85mA playing
  • File system: FAT16
  • Audio out: line level stereo (1/8" stereo jack), see app note below if connecting to amplifier or PC
  • Trigger inputs: 3.3-5V, active low inputs with internal pull-ups
  • Serial: Full duplex, 8N1, 38.4K baud

MP3 Trigger v2 Product Help and Resources

Tsunami Hookup Guide

February 16, 2017

Hit the ground running with Tsunami, the Super Wav Trigger.


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • Member #189512 / about 13 years ago * / 2

    This has got to be one of the coolest devices you carry. We use it in a children's museum to replicate the sound of a submarine with engine hum and sonar ping as background sound and separate triggers for "Dive, Dive", "Surface, Surface", "Man battlestations", and submarine alarm. IT IS JUST DAMN COOL ! We will use it for sounds in the museum train room when we finish with the sub room.

    • be_more / about 13 years ago / 1

      Sounds great! - Wondering if you still have these sound files?
      Some friends and I are looking for the exact same application for a replica of Jules Verne's "Nautilus" that we are constructing, using this trigger with sound files like you described.
      Do you think it'd be possible to email them to me?
      Thanks so much!

  • SidR / about 15 years ago / 2

    Does the LED light up while playing a file?
    (We trigger 11 outdoor scenes from a sound trailer for our outdoor living nativity and can't hear what is happening at the scenes)
    Pushing the Navigation Center stops the playing track. Does the track then start from the beginning next time?

    • robertsonics / about 15 years ago / 1

      There are 2 LEDs. Red LED indicates power, Green "status" LED indicates that a track is playing.
      Center position of the navigation switch is Start/Stop. Pressing it while playing a track stops that track. Pressing it again starts the same track from the beginning. (It's not a pause button).

  • robertsonics / about 15 years ago / 2

    Yup - that's the correct programmer and yes, the MP3 Trigger has in-circuit programming capability. The MiniProg can be temporarily inserted into an unpopulated ISP header location for programming. I can post 2400 and 9600 baud versions of the firmware and provide links here.
    Your idea of having an init.txt file on the Flash card is a good one, and I'll consider it for future updates.

  • jadudm / about 11 years ago * / 1


    I accidentally missed the fact that this product description is out of date. As of July 2013, this is the current version of the MP3 Trigger.. It is possible others will make this mistake. I'm leaving my confusion here as a record for others.

    I am so smrt.


    The datasheet link in the product description is from 2010. The current datasheet is from 2012. Please update the links in the product description. Actually, here is the link to the version 2.53 firmware documentation for the MP3Trigger, hosted at I'm have not checked what is shipping on the boards going out (I should), but I know that this documentation was correct for my board in ways that the documentation linked in the description was not.


    The filename format has changed; in 2013 (July) you want to be naming your files NNNxxxx.MP3, where NNN are numbers, and 'xxxx' are any characters. 003-mysong.MP3 is fine. This is at odds with the 2010 datasheet, and was the source of two hours of confusion on my part.

  • heterojunction / about 12 years ago / 1

    Does anyone know if the MP3 Trigger will play multiple sound files simultaneously? or will it only play one file at a time? I would like to play multiple files simultaneously. Other than multiple units anyone have any ideas of how to achieve this? Thanks.

    • MikeGrusin / about 12 years ago / 1

      It will only play one file at a time. Until we have something that can do so, you would need to use multiple boards, or build your own player using a more powerful system such as a Beagleboard.

  • rahji / about 12 years ago / 1

    this thing works great. when i use 8 ohm headphones it's fine, but if i try 32 ohm studio headphones (i've tried several different pairs) it freaks out. any idea what the easiest solution is?

  • rahji / about 12 years ago / 1

    this thing works great. when i use 8 ohm headphones it's fine, but if i try 32 ohm studio headphones (i've tried several different pairs) it freaks out. any idea what the easiest solution is?

  • michaelshiloh / about 12 years ago / 1

    I'm using Arduino to send messages via the serial port to start a track playing. If I send the start/stop navigation command like this:


    the first (actually only) track plays

    However if I use the binary trigger command:


    it doesn't play.

    Any ideas?

    • jordansears / about 12 years ago / 1

      here's my working code! got it working with the Arduino Mega. i didn't use print, should be Serial.write i believe. and use ('t') instead of p.

      int outPin = 1; // output on digital pin 1 int outPin1 = 18; int outPin2 = 16; const int piezoPin = A0; // piezo connected to analog pin 0 const int threshold = 300; int valueP = 0; //int buttonState = 0;

      void setup() { pinMode(outPin, OUTPUT); pinMode(outPin1, OUTPUT); pinMode(outPin2, OUTPUT); Serial.begin(38400); Serial1.begin(38400); Serial2.begin(38400); } void loop() { valueP = analogRead(piezoPin); delay (1000);

      if (valueP < threshold) { Serial.write('t');
      Serial.write(1); Serial1.write('t');
      Serial1.write(1); Serial2.write('t');

      delay (30000);


      else if (valueP > threshold) { Serial.write('t'); Serial.write(2); Serial1.write('t');
      Serial1.write(2); Serial2.write('t');

      } Serial.println(valueP);


      • michaelshiloh / about 12 years ago / 1

        Indeed. Here's how I got it to work finally:

        Serial.write('p');  // YAY

        this worked for volume control as well:

        void setVolume( byte vol )
          Serial.write( 'v' );
          Serial.write( vol );

        now I can join the crowd of people in love with this device. It is so very satisfying to control! Will certainly be in many future projects as well as in my classes (I teach Arduino et al)

      • jordansears / about 12 years ago / 1

        damn that didn't quite post like i wanted it to now did it

        • michaelshiloh / about 12 years ago / 1

          gotta use 4 spaces in front of your code to cause the correct formatting. see "formatting help" button below the comment box (to the far left of the "submit" button).

  • jordansears / about 12 years ago / 1

    hey guys, please help me out! i have (3) MP3 triggers here. i've hooked one up to arduino duemilanove and have it triggering 2 tracks via serial. all good. i'm wondering about (2) things:

    1. how do i trigger the other 2 mp3 triggers to do the exact same thing? I have them hooked up via the TX to RX inputs from one another (daisy-chain style i guess you could say?) and everything is running off USB power from the computer. I'm thinking that it's not enough power? I tried plugging 2 of them in by AC->DC wall wart (9.6V) and the things didn't even turn on when i switched them to EXT power.

    2. i'm planning on splitting apart the RCA outs and running each end to its own powered monitor. is this going to cause me problems???

    please post up, i have a huge crit for my thesis project on wednesday and this is the core of it!



    • dannil10 / about 12 years ago / 1

      I tried both your solution (in essence parallelling the RX inputs of the trigger boards and connecting them to the same TX port if I understand you correctly), which did not work for some reason. My next step was to try using NewSoftSerial transmitting from two different pins but this was also unsuccessful (anybody out there who's got it working that way?). I ended up using two communicating Arduino Pro Mini boards with a master-slave relationship - enabling me to hook up one true serial port to each trigger board. But honestly I have absolutely no idea why either of my other attempts (parallel connection to the same TX port and two different NewSoftSerial ports, respectively) would not work. Any ideas anybody? The answer to your second question depends on the input impedance of your monitors, but I have successfully driven two pairs of headphones with one trigger board, so I doubt that you will have any problems as long as your inputs are decently standard.

      • jordansears / about 12 years ago / 1

        wow thank you soo much for replying! i have a friend who recommended using the arduino mega, so i'm gonna go and pick that up from him today. i really have no clue why you can't chain the mp3 triggers. i'm splitting the RCA cable and just running each in put into two separate powered monitors so hopefully it works! i really appreciate you trying this out. i'll let you know how the mega handles it (it has 3 serial outs) sweeet.

        • dannil10 / about 12 years ago / 1

          Good luck with your work, and yes, please let me know how the Mega does it. Did you resolve the power issue? With enought external power, I don't see why the players would not run. Did you make sure you have the latest version of the firmware? If not, download it and install it on each board according to the instructions on MakerJam. These little boards are very useful, but also a bit cranky unless you treat them exactly right, and how to do that is not always very well documented, or maybe even investigated. When hooking up two boards to the same power supply and sound system I also ran into problems with HF interference which I attributed to some ground loop. I don't remember exactly how I got rid of it, but it involved trying different ground connection points betweenthe two boards.

          • jordansears / about 12 years ago / 1

            great i'll take that into consideration! i think i was just worried because i thought i saw something about if you don't have a buffer between the RCA and the powered monitor, the actual chip on the mp3 trigger can be harmed somehow. do you know what's up with my power problem? those things should have turned on with the switch set to EXT and a 9.6 V adapter goin in!

            • dannil10 / about 12 years ago / 1

              9.6 V should be fine, and each board should draw considerably less than 100 mA. Do the boards run OK on USB power? If they do, and assuming your wall wart is working OK (did you double-check?), the question of correct polarity remains. Centre positive if I remember correctly, but check the data sheet (no offense, I just make that kind of mistakes all the time myself, unless I'm paranoid with the multimeter :-) ). If you can't make any of them run on USB power, you should try the troubleshooting guide on MakerJam. There's a step by step recipe with test files and other stuff. There is an application note for the chip recommending addition of RC networks to counteract static discharges if you connect it to external audio equipment. Though this may be a good precaution, I haven't experienced any static-related problems in my own projects, including one permanent museum installation with long headphone leads which has survived for two years in a tough environment, and another semi-permanent gallery installation which has been running for several months.

  • Member #83790 / about 13 years ago / 1

    Great product Mr. Robertson, too bad you did not take the time to tell us which microSD card works at high bit rate. So far I tested the 2gb from Kingston and Sandisck and no one will play an mp3 properly. I have to reduce the bit rate, a hassle! I will keep testing more cards but that something that you should have done and share “brand name” before start making money out of this item. My next try is going to be Memorex traveler microSD, it claims to be class 6.

    • robertsonics / about 12 years ago / 1

      I'm sorry you were having difficulty finding a card that will support 192kbps MP3 playback. I just posted a firmware update that not only adds support for FAT32 formatted SDHC cards (finally) but also includes some code optimization that allows for 192kbps MP3 decoding on a wider range of cards. It works on all the "slow" cards that I have in my possession. I'll be curious to hear if it fixes your issues.

      Please note that this firmware update adds support for using FAT32 SDHC cards with the firmware. The bootloader in your unit still only supports FAT16 SDSC cards so please keep at least one around for future firmware updates.

      Get version 2.50 here.

  • wbaldwin / about 13 years ago / 1

    It appears from the schematic that the minimal RC protection documented in the "VLSI Application Note for protecting analog outputs" has been taken care of on the MP3 Trigger board. If that is true, you might consider noting that somewhere. I am hooking the output to battery powered amplifier boards for my boy's Darth Vader Costume I sure hope I don't smoke the board before Halloween. I was unable to locally purchase an SD card smaller than 4Gb and the MP3 Trigger card would not read 4Gb Fat16 cards. I dug through my old cell phones and found a 2Gb Fat16 card and it worked great. You might consider noting that in the documentation too i.e. the Fat16 prerequisite is there but not the 2Gb limit. I am controlling it from my FEZ Panda II using Wii Numchuck for the input. My boy is going to have sooo much fun breathing on people!

  • Member #83790 / about 13 years ago / 1

    I have 3 mp3 trigger connected togueter using a single power supply (12V). Sometimes when power up the songs will not play. I have to disconnect the power and re-connect to make it work. Why that happens? I try connecting all of them using 5V (usb) and still have the same problem. PLEASE HELP!

    • robertsonics / about 13 years ago / 1

      Please make sure you are using the latest firmware, which you can get here. You want the v2.40 beta.

  • Member #83790 / about 13 years ago / 1

    Robertsonics, Could you please name at least 1 microSD card brand or post online link to buy a card that will work at high rate 192kbps ? That way we don't have to try all the cards at the electronic store. having a list will be the best. Thanks!

  • Member #83790 / about 13 years ago / 1

    The MP3 trigger only plays correctly files up to 160kbps (bit rate), greater than that any song will sounds "terrible". Is that something that can be fixed? updateing the firmware? is a hassle to convert the files every time before loading into the microSD card.

    • robertsonics / about 13 years ago / 1

      It's likely the brand of microSD card you're using. Please see the section on flash cards here

  • Member #257722 / about 13 years ago / 1

    I had to use 2GB Sd cards. 4GB would not work, even when they were FAT-16 formatted

    • robertsonics / about 13 years ago / 1

      Anything above 2GB is an SDHC type card and requires different initialization firmware to work, so it's more than just FAT16 vs FAT32. Read the section on flash cards here

      • Diego_1 / about 12 years ago / 1

        Hello Robertsonics.

        I just purchased one of the boards ( if all goes well ill be getting lots more) an dim having an issue.

        The purpuse of the MP3Trigger is to play either random mp3s or on by one via an motion sensor. I have plugged the sensor to one pin and it failed to play the next song after it detected it. Also, Im pluging an Arduino ONE to one trigger port and every time send a trigger it plays the same mp3, what do you suggest?

  • DMaurer678 / about 13 years ago / 1

    I have an application that will have a single MP3 file that will be triggered by a single input. What does this board do when a trigger is applied while a file is playing? Will it; A) abort the playing and restart from the beginning, B) wait for the file to finish playing and restart or C) ignore the trigger? I'm hoping the answer is A.

    • RobotDude / about 13 years ago * / 1

      It will do option A. It stops the currently playing file and begins playing the triggered file immediately.

  • Member #36903 / about 13 years ago / 1

    Concerning the isolation of the output ground: I tried using a 600 to 600 ohm audio transformer (Jameco #630459) and it worked well. It provides the isolation needed when one wants to use one power supply for the MP3 and the amplifier.
    Does anyone know if feeding the output of the MP3 into the primary of this transformer will do any harm? Should I use a capacitor in series with the primary?

  • Member #257722 / about 13 years ago / 1

    Is there a simple way to make the board trigger only once each time a connection is closed? I want to trigger a stomping sound when a pressure switch is activated, but I don't want the sound to repeat until the switch resets and then is activated again?

  • R2BuilderAZ / about 13 years ago / 1

    I connected the MP3Trigger (v2.40beta) to a Bluetooth Serial board and for testing purposes I am connecting via a Bluetooth Terminal Window on com5. If I type in F, R, T1, T2, T3, T4, T5, T6, T7, T8, T9, O, S0, S1 everything works fine.
    S0 returns: =MP3 Trigger v2.40e
    S1 returns: =5 (That is the correct number of track I have at present on the 2GB SD card, that will be increased to 250 or so later on.)
    Have not tried the v command as the volume is fine at the stock level for now.
    If I type in Q0, Q1 nothing happens so I have no idea what is going on with those settings.
    If I type in t1, 't'001, t001 I get an error returned.
    I also tried to cut and paste the command t1, t001 in case my typing is too slow, still no dice. So is there something I am missing here to make this work?

  • BaronVonDarrin / about 13 years ago * / 1

    Warning: total newb here. My goal: have unit sit on at idle not playing any sound, play mp3 sound when corresponding button is pressed. Nothing more. Can I achieve this at-stop/file selection-play-stop without a microcontroller? Any help is appreciated. Thank you

  • thesite / about 13 years ago / 1

    Can this decode ogg/vorbis?

  • Member #241991 / about 13 years ago / 1

    I have not been able to post on Makerjam so I am posting here.
    I have recently purchased the mp3 Trigger V2 and installed the 2.40 Beta firmware for it's improved file naming convention.
    I am building an effects box with a series of buttons. Each button triggers changes in lighting and sound. On a button press, the mp3 Trigger serial commands are sent only one time. Everything works great and as expected except that the serial trigger will not start a new track unless the current track has stopped playing. The volume commands work regardless of playback state. It is just that the track commands are ignored until the current track ends. Is there a way to get the new track to start immediately upon sending the trigger command?

    void playTrack( byte trackNr )
    byte cmd[2] = { 't', trackNr };
    Serial.write( cmd, sizeof(cmd) );
    void setVolume( byte vol )
    byte cmd[2] = { 'v', vol };
    Serial.write( cmd, sizeof(cmd) );

    • robertsonics / about 13 years ago / 1

      It is the intent that serial triggers should act immediately and it certainly used to work that way. To be honest, I haven't specifically tested this after the last couple of firmware updates, so perhaps I broke something. I'll look into it and will post back here by tomorrow PM. (Not near the hardware today.)
      What was the problem posting on Makerjam?

      • Member #241991 / about 13 years ago / 1

        Thanks for looking into it. If I need to roll back to an earlier firmware please recommend one.
        On Makerjam, I have trouble entering text into the forum post text box; e.g. if I move the cursor out of the box I can't reenter and continue editing and I can't select any of the formatting options. Also, when I have carefully gotten my message entered and submitted it, along with the test math, it appears to accept the post but the post does not appear. I am using a Windows 64 bit machine with the current version of IE.

        • robertsonics / about 13 years ago * / 1

          I just tested an MP3 Trigger V2 with the latest firmware, version 2.40e, using an FTDI Basic connected to the serial control port and HyperTerminal to type commands. I have 9 tracks on the microSD card named 000Track.mp3 through 009Track.mp3.
          If I type "T1" to start track 001, then "T2", track 001 stops and track 002 starts immediately. It behaves this way no matter what combination I use. Serial command always start tracks, regardless if another track is already playing.
          I suspect you may have some issue with your serial port that depends on getting a receive character. Remember that the MP3 Trigger sends an "X" when a track completes. Perhaps this has something to do with your problem?

          • Member #241991 / about 13 years ago / 1

            I am using the lower case "t" command per the manual which seems to indicate that the upper case "T" command can only trigger the first 9 tracks while the "t" can trigger all 256. I have many tracks to trigger. Also, I am using a micro controller to send the commands from software with the code examples in my first post. My code triggers the new track but only if it's sent after the current track ends. I'll try to debug the serial comms between the boards. Thanks for looking.

            • robertsonics / about 13 years ago / 1

              There should be no difference between the "T" and "t" commands with respect to starting tracks. The difference is only how the track number is sent. The upper case command uses an ASCII character, "1" through "9", which you can type on a keyboard. The lower case command uses a binary value which can be 1 through 255. But they otherwise behave the same.
              Is your micro controller receive data pin connected to the MP3 Trigger transmit pin? The MP3 Trigger sends an "X" when a track completes.

              • Member #241991 / about 13 years ago / 1

                I had time tonight to figure out what I was doing wrong. With each button press I was setting the volume and immediately playing a track. My commands were too close together and the Trigger was missing the play command. I but in a slight delay (50mS) between the commands and it works perfectly now.

  • Member #205590 / about 13 years ago / 1

    I am not able to play from a 4GB micro SD-card even if it is formated as FAT16 using windows 7.
    I get one long blink at startup.
    The same cards plays OK with a 2GB card.
    Is it not possibe to use cards greater than 2GB?
    (They are difficlt to come by nowadays...)

  • zzl630 / about 13 years ago * / 1

    For those who spent the whole weekend working on stupid SDSC/SDHC issue like I did. Try download this sd card formatter, it solve my problem. Especially Windows 7 user.

  • Member #160824 / about 13 years ago / 1

    I purchased 5 of this one is burned out.
    tried second and third one,
    tried a lot of things with different rates like 16,128,192kbps in .mp3 formates but it does not detects mp3 files.
    One of my 2GB card damaged.
    I formated 4 GB cart to FAT format in my laptop from FAT & FAT32 format.
    Please guide what to do.
    Really disappointed from this product

    • robertsonics / about 13 years ago * / 1

      What you are experiencing is certainly not typical. Try carefully following the MP3 Trigger V2 Troubleshooting Guide here. This should help you determine whether you are doing something wrong or if you need to contact SparkFun technical support for repair or replacement.
      And read the section on microSD card types here

  • Member #240476 / about 13 years ago / 1

    Does anyone know the power output to the speakers? I need 1.5 watt at 8 ohm to drive my speakers

  • Member #240476 / about 13 years ago / 1

    any ideas how many watts this puts out? I need 1.5 watts to drive my speakers.

  • Robert451 / about 13 years ago / 1

    This is an excellent board. I've used these successfully on several project. On my current project I'm running into a problem. When I start up my robot, the MP3 board status light flashes three times quickly and then goes off (indicating everything is OK). Then after about 20 seconds, the green status light starts flashing and the speaker starts clicking: click-click-click-click-click... The frequency of the flash (and the clicking) is about 3 times a second. The MP3 datasheet indicates "Constant short blinks - Hardware problem with MP3 Decoder." Does this mean my mp3 has burned out or is otherwise damaged? Or does this mean I have set it up incorrectly (such as a power, grounding or other problem)?

    • robertsonics / about 13 years ago * / 1

      The symptoms you describe are not normal behavior, and this is not the "constant short blinks" indicated by the datasheet. Please check the troubleshooting guide at
      Disconnect everything except power - this includes anything you may have connected to the trigger inputs or serial port. Ideally, use a power source known to work, and remove any init file from the microSD card. If you still observe this behavior and/or cannot play a track using the navigation switch, then something is indeed wrong with your MP3 Trigger and you should contact SparkFun tech support.

  • pvanderbilt / about 13 years ago / 1

    How do I connect an MP3 Trigger to an Arduino Uno? Can I just connect Arduino TX to Trigger RX and vice versa (and Gnd to Gnd)? Is there an issue with the Uno running at 5V while the Trigger runs at 3.3V?
    Alternatively, can I connect an Arduino pin to a Trigger pin and have the Arduino digitalWrite(p, LOW)?

    • Robert451 / about 13 years ago / 1

      I am not a Sparkfun person, just a user, but I have successfully connected my MP3 Trigger to an Arduino Uno. Yes, I connected the TX to the RX and vice versa to handle the serial communication. I then wrote a little sketch to open the serial port and send commands to the MP3 player. It's simple and easy. Just a few lines of code.
      There is a solder jumper on the MP3 board to allow it to run either at 3 volt or at 5-12 volts (labeled "VBUS"). You could connect the Arduino to a Trigger pin, but that's not nearly as flexible as the serial approach. On the other hand, the serial approach does take up your serial pins on your Arduino. With the latest firmware of the mp3 board, you can set the baud rate from 38400 to 9600, which would allow you to use the Arduino NewSoftSerial library, which allows you to make any digital pin into a serial port (so you don't use up your dedicated serial port).

  • Jalockit / about 13 years ago / 1

    Ok so just to clarify, the GBUF, Left, Right, protection capacitors/resistors shown on the schematic, do not provide protection to connect the minijack output to an external amp
    (i.e. the minijack outlet is GBUF, Left Right and not Ground, Left and right) is this correct?
    Is there a solder pad for Ground, Left and right that utilises the onboard protection?

  • Member #223601 / about 13 years ago / 1

    I'm currently using 2 different Mp3 trigger units (LOVE THEM!)with small self amplified computer speakers. Have I just been lucky about this output buffering issue, or am I safe in using that type of amp. Do you make a buffer board that I can order with each MP3 trigger unit. Worries me to have to think about building a separate board just to make it play back through anything but headphones.

  • Member #227087 / about 13 years ago * / 1

    Awesome Board. First time using serial.
    Any resources on where to find example sketches?

  • df / about 13 years ago * / 1

    hey guys,
    i added the buffer to my mp3 trigger so i could plug it into a stereo, which worked out perfectly. i thought it might be useful for some people if i posted a picture of my layout—feel free to use it! it's unlabeled, but pretty intuitive. (ground runs down the middle)
    and here too:

  • geewillikerz / about 13 years ago / 1

    I'd making a device which will be plugged into an external P.A. System, so I'm Looking at the VSLI external protection document. It seems that fig. 8 is the way to go for me, but the values of C1and C2 are not labelled. Any suggested values?

    • Bob_NJ / about 13 years ago / 1

      The calculation of the coupling cap value is described in Para 3.1 (just above Fig 8).

  • merceditas008 / about 13 years ago / 1

    Hi!- Im trying to do a serial communication between the mp3 trigger and arduino duemilanove and I cannot figure out what im doing wrong!I just wanna play and stop and "track001.mp3". So far I just got it looping through the digital pins so I assume Im wiring&feeding the mp3 properly (and the content in the SD card is correct)but if I start with Serial they dont talk anymore. The commands apperar properly in the arduino Serial Monitor with the delay I have set (I can see there "Q0t1Q0t1..."). I have tried all the different versions I have seen online of playing track 1 (Serial.write('t'); Serial.write(1); or Serial.print('T'); Serial.print(49); or using the David Wicks library..)
    any suggestion?

  • Member #215379 / about 13 years ago / 1

    I'm totally new to Arduino (and electronic stuffs)
    I want to do a musical box. I'm thinking about use this shield. My question/concern is related to the power supply. I want to have an arduino controller, its power supply must be a battery that I can charge using an USB port (similar to an ipod or any other mp3 player). Then I want to connect this MP3 shield to the arduino to control the songs. The mp3 shield should take its power from the arduino battery. Additionally I'll use some passive speakers that will take the power from the mp3 shield jack. It's this possible? In short I want to do something similar to that:

  • Member #209041 / about 13 years ago / 1

    I'm building the mp3 trigger into a box with a mono output. Thus I want the left and right signal to be mixed together into a mono output.
    Is it safe just to connect the two signals directly? Do I risk harming the unit in any way? Should I perhaps put a resistor. And if so which one?

    • robertsonics / about 13 years ago / 1

      A better and simpler way would be to encode your MP3 file as mono and then only use either the left or right output pair.

      • Member #209041 / about 13 years ago / 1

        Thanks for your reply.
        Well yes. No need to complicate things. Thats what I think to.
        But my intention is to be able to choose between mono and stereo output. Like on many music effect machines. I want two mono jacks out. If I use them both I want left and right. If I use the left only I get left and right channel mixed in one mono signal.

  • Member #35561 / about 13 years ago / 1

    Hello, has anyone tested this board with the Audio Amplifier Kit - STA540 ... it's the one that shows up on the related products list below?

  • femur / about 13 years ago / 1

    All of my tracks are sounding "wavy" when I try to play them back. Another description would be that they sound like they are "pulsing". They trigger fine and play all the way through but just sound wrong. I have tried exporting MP3's from itunes and audacity at bitrates 128K, 160K, 192K. All sound the same. Fine on the computer but wavy on the module. Tried two different sets of speakers too.
    Any ideas? Thanks!

  • mdicillo / about 13 years ago / 1

    Hey guys,
    First of all, I just wanted to say how awesome your company is. I was well informed throughout the entire ordering/shipping process, and the products arrived very quickly. You guys rock! Now, on to a tech question: I have a MP3 trigger (which works beautifully) and I have that connected to an Arduino Uno. I have it setup using the NewSoftSerial library and it works like a charm. Everything works exactly how it should. BUT, when I have a tiny Radio Shack speaker connected to the output with an 1/8" plug, it seems to be somehow interrupting the Hardware Serial print function. Weird, right? Is there some sort of power issue going on? Does the MP3 trigger use more juice when it knows a line out is connected? It's not the code because I can sit there and run the program with the speaker connected and get nothing from the Hardware Serial, but as soon as I physically pull the plug for the speaker out of the MP3 trigger, the Hardware Serial outputs exactly what it should. If you any info or insight as to what could be going on, I would love to hear it...Thanks again for being an awesome company!

  • Aardpeer / about 13 years ago / 1

    Hi there,
    I'm working on a project with the MP3 Trigger. All is working fine but I'm trying to figure out if it's possible to use an external SD card reader/socket such as the Breakout Board for microSD Transflash (sku: BOB-00544) to make it easier for users to switch SD card.
    Since the connections are all solderd away I can't connect it 'parrallel'. But does anyone know a different way to connect it?

  • Gary4 / about 13 years ago / 1

    I can't find any way to pause the trigger board. I also don't see any open source code to redo the firmware. Is there any chance that we could get a new version of the firmware with a Pause command?

  • Robert451 / about 13 years ago / 1

    I love this mp3 trigger. In my first use of it, I created sound effects for one of my robots. I'm now working on my second project and running into trouble. Everything's working fine, except when I try to play mp3 files of songs that I've purchased from Amazon (digital downloads similar to iTunes, but theoretically they have no digital rights management in them). When I play these songs it sounds jittery, skippy, garbled. I have a feeling it's some sort of encoding speed mismatch problem, or something like that, but I don't know how to resolve it. Is there a solution? If not, do you know of any place I can purchase popular songs (Elton John, etc.) that will play on this MP3 board?

    • Member #189512 / about 13 years ago / 1

      Try converting the audio file using Audacity. It's free and worked great for me.

    • Bob_NJ / about 13 years ago / 1

      I had a similar problem with garbled/distorted audio. The problem was the bit rate was too high. The MP3Trigger should work OK with 192kbps (and lower) sample rates using the latest firmware. First, check the sample rate by right-clicking your file in explorer and choosing Properties. If it is 192 then you may not have the latest firmware. Go to for files and instructions. If it is greater than 192 then convert the file to a lower sample rate. There are several PC utilities available for this purpose.

  • Stormwulf / about 13 years ago / 1

    Seems like this is a common issue with the Trigger, but I'm trying to control the volume using PIC Basic to no avail.
    I'm sending the following using a serial command:
    serout2 TRISB.3,396,["v", bin vol]
    I've tried sending the volume value in binary, hex, decimal indicated and not indicated and I can't get it to work.
    Any help would be greatly appreciated.

    • robertsonics / about 13 years ago / 1

      Not sure what you mean by a common issue. People do sometimes have trouble getting the correct serial format but I'm not aware of any problems with the volume command per se.
      Do other serial commands work? If not, I suggest that you focus on getting other commands working first - perhaps just starting audio with the "O" or "F" commands. If other commands are working, what values of volume are you sending?

      • Stormwulf / about 13 years ago / 1

        Sorry, I didn't mean to say there was a design problem with the board itself, but it seems that people do get confused on exactly what to send to control de volume.
        I've used the other ASCII commands and they work great, I can get music playing, stop, request status, etc, but volume is giving me trouble.
        As I understand the specification, volume seems to work "backwards", 0 being the loudest, 40 being the lowest, is this correct?
        Do I need to format the number in a special way? as you can see in the command I'm using I'm telling PICBasic to send the value of vol in a binary way.
        Thanks for all the help =)

  • hfkids / about 13 years ago / 1

    I have what for all of you is a most simple project. I'd like to be able to push keys on a sparkfun matrix keypad and then have the MP3 trigger play different files (out of a selection of 100+ sound files). I have the keypad connected to an Arduino Uno. So do I simply connect the Arduino Uno TX line to the MP3 Trigger V2 RX line? and have the baud rate set for 9600 bps? then find some Arduino code that allows me to send a "t" and the sound file number to the Trigger V2? is that it? or do I need to convert an analog port/pin on the Uno into some sort of softserial comm port? (I've been reading lots of threads but don't quite get it). Any help is really really appreciated.

    • robertsonics / about 13 years ago / 1

      Pretty much, yes. You'll need to also connect GND and you may also want to connect 5V to power the MP3 Trigger from the UNO. So that's 3 wires total. The default baud rate of the MP3 Trigger is 38.4k, so if you do want to run at 9600, you'll need to update the MP3 Trigger firmware. Finally, people seem to have the most trouble with the fact that the "t" command takes a binary (non-ASCII) value as the second byte. So to start track 55 for example, you need to send the ASCII character "t" followed by the binary decimal value 55.

      • hfkids / about 13 years ago / 1

        thanks for the advice. that works great. next up is a programming/functionality question: once a file is playing, may I send the Trigger a "v" command to change the volume up/down thereby varying the volume mid-song (without disrupting the song's playback)?

        • robertsonics / about 13 years ago / 1

          Certainly - that's what it's for. If you need smooth volume changes, you'll need to experiment with how often to send them. If you send large changes infrequently, you'll hear the steps. If you send small changes too rapidly, you will interfere with audio playback.
          If you are sending volume changes in response to say a button push, no problem. If instead you are using an analog signal like a pot, then you'll need to limit the volume commands to no more often than once every 20 to 50 milliseconds.
          There is code in the MP3 Trigger to smooth out changes in volume, and sending volume commands too rapidly can take cycles away from playing audio and cause glitches.

  • Member #195948 / about 13 years ago / 1

    I'm currently working on a project to play different bird sound MP3's. My employer would like a keypad as the trigger. My experience lies more in programming and less in electronics. My question is there a way to hookup a 12 Button Keypad such as
    directly to this device or do I have to go through some sort of arduino to activate the triggers.
    I only need access to 18 tracks total.

  • Member #195232 / about 13 years ago / 1

    This question is for SparkFun: Do you have an operating temperature range specification for this board? I did not see it on the datasheet. Thanks.

  • Perl / about 13 years ago / 1

    Can you guys tell my why you chose the CY8C29466 and not an ARM or AVR based chip?

  • geewillikerz / about 13 years ago / 1

    I love this thing! Thanks for making it.
    2 questions, though:

    1. Power.

    Right now I'm giving it 6V from batteries to the external power jack while the mini-switch is set to EXT, or 5V to the USBVCC pin (red wire of FTDI cable or 5V pin from an arduino) while the mini-switch is set to USB and it works. If I cut the solder bridge at the bottom left (#4 in Figure 1. in the user guide) between the centre and VBUS and solder from the centre to 3.3V will the board then run with a 3.3V regulated source to the USBVCC pin with the mini-switch is set to USB?

    2. ??

    I'm having a strange problem with one unit that I made based on this board. Occasionally (10% of the time? 15%?) the audio out will send no signal. The power LED is on, and when I close any of the triggers the green indicator LED will light for the length of time that the track would last, but no audio comes out. I can turn the unit off and on again and it starts working again. I've been trying to eliminate everything that I have added, but this intermittent problem still crops up. Anyone else experienced the same thing, or have any clues what could cause it?

  • Output Arts / about 14 years ago / 1

    I just wanted to leave a note to say that we used an MP3 Trigger board in a recent audio art installation. It saved me a ton of time building a custom decoding unit (which I have done in the past) and Robertsonics was really helpful.<br />
    <br />
    There's some pictures of the piece in place on our website (including some naked electronics porn in the setup gallery linked at the bottom of this page):<br />
    <br /><br />
    <br />
    Fantastically useful piece of kit.

  • y0shiy0shi / about 14 years ago / 1

    Hello all. I'm a new arduino programmer so I apologize if this question seems n00bish. I need to create a project where a pushbutton trigger tells the arduino to begin playback of an mp3 an exact point during the song. I also need to get some sort of sync track (much like smpte) where I can get a running time of the song that is accurate (as opposed to me beginning my own duration time track based on when the mp3 beings playback from the beginning. I cannot find any documentation that tells me if this is posisble. is this trigger v2 only designed to begin playback from the beginning of the track? I have already purchased the mp3 shield before I realized that mp3 trigger shield was more a "finished" product. If this trigger cannot do what I need, does anyone know if the mp3 shield has the capability? The end result is that I need to 1) trigger playback at certain times during a certain track 2) have a synced runtime counter that is accurate for display and duration bar.

    • You can only select tracks, not track position. Unfortunately, I am not aware of anything meeting your requirements. You might have to modify the firmware, or roll your own, sorry!

  • steambc / about 14 years ago / 1

    Can this unit play 9 separate mp3 files sequentially via a SINGLE pushbutton?
    I'd like to push the momentary contact button once, and song 1 plays until it ends. Push it again, song two plays until it ends. On it goes until song 9 plays. The next button push will play one again, then two, etc.
    I would really like to avoide using a microprocessor for this project as I'm restoring an antique coin0op machine. Thanks for any help!

    • robertsonics / about 14 years ago / 1

      Yes, if you go here and get firmware version 2.23r. With this alternate firmware, TRIG17 will do exactly what you want; namely cycle through all tracks on the card - one track per trigger pulse. If you jumper TRIG17 permanently active, then it will play all tracks continuously one after another. TRIG18 will do the same, except in random order.

  • Nicodemus / about 14 years ago / 1

    Is it possible to have the files NOT to loop?

    • robertsonics / about 14 years ago / 1

      Tracks do not loop unless the corresponding trigger is held active. A single pulse on a trigger will cause the track to play only once.

  • Nakor / about 14 years ago / 1

    I read through the manual and I don't see any commands for start and stop at specific points in a track. Has anyone hacked this in (or am I missing a command)?
    How hard would it be to directly access the SD?

  • goose / about 14 years ago / 1

    I haven't recieved my mp3 trigger yet. But I want to interface it with a pic16f88. Any advice? I'm mostly looking for what connections I should make with the pic to the trigger, and any quirks that might be a problem in terms of coding.

  • kmo / about 14 years ago / 1

    Hi, i?m using MP3 Trigger V2 with Arduino (doemilanove), i need the library patch for the Proccesing.

  • stereomuffin / about 14 years ago / 1

    Heres a quick demo using Mp3 Shield and Arduino:
    Would it be possible to somehow influence the pitch of the played back samples? (like the waveshield can for example)

  • Ford Anglia / about 14 years ago / 1

    Is the CY8C29466 IC programmed by SFE to contain the bootloader code? Is that the reason for the five pads on the backside of the PCB and under the PSOS IC? Is the Bootloader code available, to flash a replacement PSOC device?

    • robertsonics / about 14 years ago / 1

      As you may be able to tell from the schematic, the pads on the back of the board are the in-circuit programming connections - JP9 on the schematic. This is used once during manufacture with a Cypress MiniProg to program the bootloader. The firmware is then loaded from a flash card using the bootloader. The bootloader is not generic - it's specifically written to support the MP3 Trigger hardware.
      If you are at the point of replacing a PSoC, and you just purchased the unit - I'd think it would be easier to contact tech support for a replacement.

      • Ford Anglia / about 14 years ago / 1

        Thanks for confirming my observations. The unit I have came in the "Ding and Dent" bag - the challenge is to make it play! Actually, it does play MP3 files, the manual switch works (after fixing bad soldering) but none of the triggers work. This is one of three dead units I have. Another has identical issues (but no bad soldering found so far). The third has no audio.
        So as you seem informed about the project, can you supply the bootloader to allow replacement and programing of the PSOC chip?
        Also, do you know what the test conditions are to cause "Constant short blinks - Hardware problem with MP3 Decoder"?

        • robertsonics / about 14 years ago / 1

          Constant short blinks means that the PSoC had problems communicating with or initializing the VLSI VS-1053 decoder. It also means that the PSoC is running, so replacing or reprogramming the bootloader is not indicated. It's more likely the decoder IC or the solder connections to it.
          When audio plays using the navigation switch, but all the triggers appear to be non-functional, it's usually a problem with filenames. There are other posts here about this confusion, but you must follow the 8.3 filename convention and name the tracks "TRACKnnn.MP3", where "MP3" is the filename extension (sometimes hidden in Windows), not part of the filename.
          If you want to discuss troubleshooting in more detail, please post in the dedicated MP3 Trigger forum on

          • Ford Anglia / about 14 years ago / 1

            Renamed the files as follows:
            Directory of E:numbers
            08/06/2010 07:47 PM 6,188 TRACK001.mp3
            08/06/2010 07:48 PM 5,770 TRACK002.mp3
            08/06/2010 07:48 PM 5,770 TRACK003.mp3
            Unit No1 operates correctly! Unit No2 does not trigger but does work correctly from the nav switch. Unit No3 has no audio, no status LED, but does have a good power LED. All three units have both 3.3V and 1.8V rails. All units show signs of reflow soldering (or possibly parts replacement). No further bad soldering has been found, so component substitution is the next step for the two dead units (the third is a good one, and now a reference for fault finding).
            Comments Welcome!

          • Ford Anglia / about 14 years ago / 1

            Thanks for the hints and background info.
            The files on the MicroSD card contain spoken numbers (as part of my diagnostic testing), and have the following file format. For example:
            Directory of E:numbers
            08/06/2010 07:47 PM 6,188 one.mp3
            08/06/2010 07:48 PM 5,770 two.mp3
            08/06/2010 07:48 PM 5,770 three.mp3

  • Ford Anglia / about 14 years ago / 1

    Constant short blinks - Hardware problem with MP3 Decoder.
    What causes this condition?

    • robertsonics / about 14 years ago / 1

      The PSoC writes and read-verifies a number of the VS-1053 control registers during initialization. If any of the reads don't match the writes, it aborts and blinks the status LED in this manner. This would indicate either a bad VS-1053, or more likely a bad solder joint on one or more of its pins (or the related PSoC pins).

  • Radiohound / about 14 years ago / 1

    Are there two types of microSD cards? My Sandisk 2GB card is paper thin, and when I insert it into the MP3 Trigger and tilt the board sideways, it falls right out. Yes, it is inserted all the way, and clicks. What is my problem?

    • robertsonics / about 14 years ago / 1

      Not that I know of. Sounds like there's something wrong with the socket - you should contact SparkFun tech support.

  • nathan.tomlin / about 14 years ago / 1

    What is the maximum mp3 file size it will play? I need a constant tone and would like to make the mp3 as long/large as possible to minimize the frequency of glitches when it loops.

    • robertsonics / about 14 years ago / 1

      Are you asking filesize or duration? The maximum filesize is dependent on the media formatting but is probably at least 1GB. The duration of the audio for a given filesize is of course dependent on the sample rate, number of channels and encoding rate.
      I'd estimate that for decent audio (16-bit, 44.1KHz, stereo, 128kbps) you'd get something like 10 hours of audio with the maximum filesize. Double if it's mono, and more if you don't need that kind of quality.
      For a recent museum exhibit, I looped sounds at around 50 minutes. If I remember correctly, files sizes were 100MB or less.
      Someone check my math. Hope this helps.

  • MikeGrusin / about 14 years ago / 1

    We've had a few customers contact us who were unable to get the MP3 Trigger to play any files using the trigger inputs, though the manual switch still works fine.
    As people have noted above, it turns out that the datasheet is wrong, and the solution is to name the files e.g. "TRACK001" instead of "TRACK001.MP3". We're working on updating the documentation. Sorry for the confusion!

    • robertsonics / about 14 years ago / 1

      The datasheet is not wrong, but perhaps not worded as clearly as it could be. The filename being discussed is the complete FAT16 8.3 format: 8 character name and 3 character extension, i.e. what you would see if you looked at the directory in a DOS prompt window. The extension is always "mp3". TRACK001.WAV, for example, will not work.
      But I guess the point is that it's confusing some people, so thanks for point this out. How would you suggest wording it?

      • MikeGrusin / about 14 years ago / 1

        Apologies for the earlier claim that the datasheet is incorrect. Files on the uSD card DO need to have an .MP3 extension for the MP3 trigger to function. So why was this not working for some people, and the solution for them was to rename them "TRACK001" etc. without an extension?
        One of our engineers, Aaron Weiss, pointed out that if you have "Hide extensions for known file types" turned ON in Windows' folder options, it's very possible to accidentally misname files. TRACK001.MP3 shows up as TRACK001, but plays correctly. But if you rename the file TRACK001.MP3, the actual name will be TRACK001.MP3.MP3, which won't play.
        So: be aware of the setting for "Hide extensions for known file types" (I always turn this off to prevent confusion). And sorry for the confusion ourselves.

  • Playful / about 14 years ago / 1

    Hi - I have a stupid problem! I just got delivery of my mp3 trigger, and went out and got a 16GB microSD card. None of my PCs will reformat the card to FAT16, as they say it is too large. I thought there must be a way to force it, and just loose the extra memory. Can you help? Or is there some 3rd party software that will do this? (btw there were no smaller cards on sale!)

    • Member #46166 / about 13 years ago / 1

      I was having the same problem & finally figured it out.
      Use the DISKPART utility as explained here:

  • ctx32 / about 14 years ago / 1

    you say:: Aside from more than doubling the number of trigger inputs,
    Does this mean instead of 18 contacts on the side it will have more?

    • Pearce / about 14 years ago / 1

      This is in relation to the previous version which only had 7 triggers. There are 18 triggers on this board.

  • VancouverMagician / about 14 years ago / 1

    I want to use my MP3 Trigger for sound effects during a theatre show. This means the line-out will be going into a theatre sound board. Typically with an IPOD or MP3 player, I just connect it with a 1/8" stereo to RCA "Y" adapter. Is this possible with MP3 Trigger? After reading the "VLSI Application Note for protecting analog outputs" it seemes like I might have an issue.
    Can someone point me in the right direction? Thanks.

    • Bob_NJ / about 13 years ago / 1

      You need to be careful when connecting the MP3 Trigger to any non-isolated electronic equipment. The 1/8" stereo jack on the board is wired specifically for use with isolated devices, like a headset. The shell is connected to the GBUF line on the VS1053 Audio Codec Chip. GBUF is NOT ground and is biased at 1.25 volts (as well as the Left and Right outputs). You must provide dc isolation on all three lines if you are going to connect the MP3 Trigger to any grounded equipment with single-ended inputs in order to prevent damaging the VS1053 chip. However, you might be able to get away with a direct connection providing the MP3 Trigger has a dedicated, transformer-isolated power supply.

  • NoiseMaker / about 14 years ago / 1

    Hi, I just purchased an MP3 Trigger and dwas looking for any info relating to max mp3 file size or other limiting factors. I saw below that the max sample rate supported is 192K. I loaded a 128K sample rate 3 minute music file and it only plays about 10 seconds and starts over. Is this normal? Short SFX mp3 files of 5-6 seconds seem to run fine. Thanks!

    • NoiseMaker / about 14 years ago / 1

      More info...After trying another mp3 convertor, I was able to rip full length stereo tracks from a CD and play them back on the MP3 trigger board at bit rates up to and including 160K. At 192K, the player plays the first 12-13 seconds and then start over, repeating continuously. Maybe it's just the nature of the beast.

      • robertsonics / about 14 years ago / 1

        Hey NoiseMaker,
        I'd like to follow up on this. Please contact me through the robertsonics website - you can send an email to info(at). or post on the forum.

  • Moey Inc. / about 14 years ago / 1

    Any chance this device will eventually read ID3 tags of the MP3s on the microSD card? This would be very useful. I know the Vmusic2 MP3 player does this but I'm not a fan of that product.

  • Jonas Bezerra / about 14 years ago / 1

    In version v2, How do I turn on my MP3 Trigger to add mp3 files via the USB port of a computer?

  • wchill / about 14 years ago / 1

    I don't suppose this allows you to send actual MP3 data to it? It all needs to be preloaded on the microSD card?
    And if only there was a version of this with write support...

  • NotHans / about 14 years ago / 1

    Here is a project over at Instructables using the MP3 Trigger in a Motion Controlled MP3 Player project.
    The project shows how to use the serial lines to control the volume of a playing track from a microcontroller.

  • r2builder / about 14 years ago / 1

    Can I attach this board directly to a 12vlt battery via the 5.5x2.1 external power connector?
    Would I be able to control the volume if I attached an amplified speaker or amplifier unit to this board? Or is the only way to control volume with the programming option described in the data sheet?

  • hunty / about 14 years ago / 1

    I see that this supports playback of up to 256 tracks via serial connection, but is there any way to configure it to play all of those tracks just via the trigger inputs by sending it a binary number through the first 8 pins and then an "execute" signal over a ninth pin?

    • robertsonics / about 14 years ago / 1

      Not with the current firmware. If you have something which is capable of producing an 8-bit selection along with an execute signal, chances are good that it's also capable of producing an asynch serial message. The former takes 9 pins, while the latter takes only 1.
      It's certainly possible, however. Perhaps an alternate firmware release, now that the bootloader makes it easy to distribute.

  • lhagan / about 14 years ago / 1

    Anyone know if this can be used with the wireless EyeFi SD card? You'd need to adapt the regular SD to MicroSD, but otherwise, I'd think it should work. Would be a nice way to change the audio content without pulling the card.

  • TechRexx / about 14 years ago / 1

    I've just purchased the MP3 Trigger and I cannot get the Trigger pins to activate the MP3 files despite correct file name and removing tags and ID3 information from the file. Can someone provide a test MP3 file that is proven to work so that I and others can determine if our coversion programs are at fault or if there is a hardware problem.

    • robertsonics / about 14 years ago / 1

      Sorry you're having difficulty. A couple of questions: Do you get 3 blinks on the status LED when you power the unit up? If not, what do you get? Are you able to play your tracks using the navigation switch? How are you activating the trigger inputs?

      • TechRexx / about 14 years ago / 1

        I solved the issue. I was adding .MP3 to the file name. I believe the manual shows this as a reminder that the files must be mp3 files. The triggers work great. As a side note, I use MusicMatch to convert to mp3s and it doesn't seem to be an issue, provided you do not enter additional track information - artist, album,etc. Next stop, using the serial commands from my BS2.
        Thanks for the quick response.

        • nathan.tomlin / about 14 years ago / 1

          Ah, I had the same problem - computer I used was set to hide the extension, so I had my file name TRACK001.MP3.MP3. That's a bit hard to troubleshoot because with that incorrect filename, you still get the 3 blinks on startup, but the trigger doesn't work. It'd be nice if it didn't blink.

          • robertsonics / about 14 years ago / 1

            The MP3 Trigger blinks "ok" because it's still a valid MP3 file and you can play it using either the navigation switch or the serial control port. It just isn't associated with a trigger.

  • Jahue / about 14 years ago / 1

    I have V1 of this and it works great. I am currently using it with some sensors and an Arduino. Does this version work with the Arduino the same way as v1?

    • robertsonics / about 14 years ago / 1

      Yup. It's exactly the same - just with 18 trigger inputs instead of 7.

  • Nolan / about 14 years ago / 1

    After reading a little more about the Arduino Microcontroller, I found the following link:
    It says that the 1 MOhm resistor should limit the voltage. Is this a safe assumption?
    Also, is there a way of connecting the Rx and Tx of the microcontroller to the Tx and Rx of the MP3 Trigger so that when a certain file name is playing, such as Kick_Drum_1, the corresponding name would appear on a serial LCD display that I connect to the Arduino?
    Thanks for your help.

  • Nolan / about 14 years ago / 1

    I recently purchased the MP3 Trigger and the Arduino Microcontroller. I also purchased a ddrum red drum trigger. I wanted the MP3 Trigger to output the audio file when the trigger was asserted. Is this possible? If so, where do I solder the wires? (I am using an open-circuit, mono 1/4" input jack and am going to solder 2 wires from the jack to the MP3 Trigger TRIG1 input)

    • robertsonics / about 14 years ago / 1

      I don't think you want to connect your drum trigger directly to either the MP3 Trigger or your Arduino. Most drum triggers are piezo transducers and capable of producing voltages that will damage 3.3V or 5V inputs. In any case, connecting it to a trigger input on the MP3 Trigger will not produce the result you are looking for.
      You will most likely need to research how to buffer the sensor signal, connect the buffered signal to an analog input on your Arduino (making certain that it doesn't exceed the voltage input limits of the Arduino), then use an Arduino digital output to activate a trigger input on the MP3 Trigger.

  • Cornercase / about 14 years ago / 1

    So far, this seems to be a good board and great for adding MP3 functionality to small projects!
    I'm having an issue with mine where I can trigger songs using the switch on the board, but if I send a command over serial from a PIC18F44J60, it only plays the track that has been selected by the selector switch rather than the track number that I'm sending. Any thoughts why this might be happening?

    • robertsonics / about 14 years ago / 1

      Most problems that people have with the serial control seem to stem from the fact that in some cases, the data byte is not ASCII but binary. Have you tried both versions of the "Trigger" command? Per the data sheet, the "T" version uses an ASCII data byte to play tracks 1 through 9, whereas the "t" version uses a binary data byte to play tracks 0 through 255.
      What exactly are you sending to the MP3 Trigger?

      • Cornercase / about 14 years ago / 1

        I'm casting an integer to a char, and then sending a 2-item char array over USART - ['t',insert integer cast to char here]
        I haven't tried sending ASCII yet.

  • ChrisParsons / about 14 years ago / 1

    Will the MP3 trigger achieve a seamless loop? I know this is difficult to do with MP3s but I'm desperately trying to find a standalone audio player that can loop audio seamlessly.

    • robertsonics / about 14 years ago / 1

      Unfortunately no. The VS-1053 requires a certain number of 0's (silence) to be sent following the end of a track, and the MP3 Trigger follows this spec. I just created a 10-second A440 tone with no silence at the beginning or end, and set it up to loop with a jumper on the trigger input. The gap at the loop point is just under a second.

  • Simpat / about 14 years ago / 1

    can we put directly this button :
    in the different trigger input ??

  • PaulMather / about 14 years ago / 1

    Great product!
    What about making one or more of the triggers work with PWM inputs from a RX? I?d love to be able to make my 3 position switch work like this:
    Middle position = Stop, Down = Play, Up = Next & Play.
    Also, if you put out another revision of the board, can you make it 1/2 the size? This thing is HUGE!

  • robertsonics / about 14 years ago / 1

    No can do. Tracks can be added to the microSD card by placing the card in a PC and copying MP3 files to the FAT16 formatted card. The MP3 Trigger has no Flash writing capability.
    Hope this helps.

  • Jonas Bezerra / about 14 years ago / 1

    How do I turn on my MP3 Trigger to add mp3 files via the USB port of a computer?

  • df / about 14 years ago / 1

    does this come with a SD card installed, or must i purchase one separately?

  • GQ4Life / about 14 years ago / 1

    This is perfect for my project. I want to use it to make custom sound when I unlock and lock my car doors. Guessing I just have to add the amp to it for more power to the speaker. Anyone know any good case for it to survive the elements?

  • Aaron Mc / about 14 years ago / 1

    This is great, even for the techinically challenged like myself. Easy to setup and use in simple trigger --> mp3 mode. will dive into reprogramming once I can figure out how to connect it to computer. Have used it in two sculpture projects - where it 7 micro switches trigger 7 different tracks - where I have 2 motion sensors triggering 2 different tracks on different channels of audio so they emit from different areas of sculpture.

  • Scott2 / about 14 years ago / 1

    This is the perfect add on for a model set I have been trying to add some sound to. Does anyone have a suggestion for the best, and smallest, speaker setup - With a volume control? I need to keep it small, but I would like OK sound from it, it will play some music and some narration.

  • darudude / about 14 years ago / 1

    I'm having trouble with the board. I'm using a FAT16 formatted card, with songs preloaded. They play in multiple computers. However, when I plug in the card and power up the Mp3 Trigger it doesn't work. The status light stays lit and doesn't blink any of the messages in the manual. Do I have a buggy board?

    • robertsonics / about 14 years ago / 1

      Remove the flash card and turn on the MP3 Trigger. After a short delay, the status LED should turn on for about 2 seconds and then go out. This is the proper response when it can't recognize any installed media. It this isn't happening, then there is indeed something wrong with your unit.
      If this does happen, then reinstall the flash card and cycle the power. If you still get the single long flash, then there's something wrong with either the unit or the flash card. If it recognizes the media but can't find any valid MP3 files, then you'll see the long flash followed by a single short one. At that point, the problem is most likely with the formatting or data on the flash card, but not hardware.
      Hope this helps.

      • darudude / about 14 years ago / 1

        Yeah the light doesn't go off after your instructions. Guess the unit is fault then. What is the procedure for getting a replacement?

        • jimblom / about 14 years ago / 1

          Please get in touch with tech support. We can set you up with an RMA and directions to return it for testing and replacement.
          - techsupport at

  • Tim-M / about 14 years ago / 1

    Hi MP3 Trigger Group,
    I just purchased a couple of units and thought I'd relay my initial experience in getting them running. I formatted a new microSD card to FAT16 to be sure it was correct and copied an mp3 file from a CD, renamed it and stripped away the additional file details of artist and style, per the manual. The MP3 Trigger recognized the file, three green blinks at power-up, all looked good. When asked to playing the file however, the output was really garbled and choppy. Being new to the device, I figured the fault was mine and that turned out to be right. What I missed is that the mp3 file I used had been recorded at a rate of 320Kbps and the MP3 Trigger supports a rate of up to 192 Kbps. I pulled the file into an audo recording/editing program called "Mixcraft" (highly recommended by the way, inexpensive/powerful) and saved it at the lower bit rate of 192 Kbps. Now the file plays just fine.
    The MP3 Trigger looks like a great product. I pass on my first rookie mistake in hopes that it will help someone else getting started.
    Thanks for the fun,

  • Drumstick / about 15 years ago / 1

    Is there a way to trigger multiple MP3 tracks and have them played back over each other?

    • robertsonics / about 14 years ago / 1

      This question comes up quite a bit, so I thought I'd address it here. The MP3 Trigger uses an MP3 decoder IC, as do all the low-cost MP3 players I've seen. In this case, the PSoC microcontroller is responsible for finding the files on the flash card and sending the MP3 file contents to the VLSI VS1053 decoder, which internally decompresses the MP3 data and outputs audio. The VS1053 can only deal with one MP3 data stream at a time, so there is no way to mix two tracks together.
      The simple and inexpensive architecture of an 8-bit microcontroller and an MP3 decoder chip just doesn't support it.
      Being able to play two or more tracks at a time would require either a more powerful CPU - one that could decompress and mix more than one MP3 data stream in software, or just mix uncompressed audio, or a wavetable synth IC. Any of these solutions would likely result in a more expensive product, and/or a lot less recording time on the flash card.
      I've been thinking about it, however...
      In the meantime, you could always use 2 MP3 Triggers and mix the analog audio at the output.

      • N.Poole / about 14 years ago / 1

        If you're trying to trigger multiple streams at once (or if you're thinking electronic drum-set, like me, perhaps the solution is to stack a few of them and run them in quiet mode with a uC on top to gather the triggers, prioritize them and send them each to different boards. At this price, that's an awfully expensive solution and it's wildly inefficient. But it is simple, lol. <br />
        <br />
        You could always use a few of the less expensive MP3 modules, as long as you're gonna use a master uC anyway. (Instead of trigger pins just call addresses.)

  • variedades / about 15 years ago / 1

    One question: I have a project that will use this incredible Mp3 trigger, but the project will use a sensor that will use one trigger at a rate of 10 to 20 hits in a trigger PER SECOND. So, with the responde time of 15ms, this should not be a problem.
    But, when the new sound is "triggered", the last one cease, and the sounds don?t overlap each other, it that correct? There is any noticiable issue about using this MP3 trigger in this hight repetition speed?
    Ps: sory by my english, my natural language is Portuguese (Brasil)

    • robertsonics / about 14 years ago / 1

      The trigger inputs are scanned at around 15msec intervals, but I can't guarantee how long it takes before the audio actually starts coming out. That's dependent on the VS1053 and the contents of the MP3 file. It seems to me that 10 to 20 triggers per second is awfully fast. What sound would you want to play for only 50 to 100 msecs?
      Regarding your question about overlapping sounds, see my answer to Erik below.

  • jasonbar / about 15 years ago / 1

    Thanks for the info. The board is already installed into our race car (yes, in the 99 Cent Store Fire Engine projet box...), so I don't have easy access.
    From memory, I did use a benchtop power supply for testing & got the same result as when using the DC-DC converter. The status light still functions & remains on solid during a lockup. I can't say exactly when it does lock up & stops responding, but it does always finish playing its sound file--it never clips the mp3.

  • nottechie / about 15 years ago / 1

    I'm just looking for an MP3 player that can be triggered by a PIR for a Christmas display.
    Will this work? I have an Arduino and Parallax's Prop-1,if that helps. My electronics skill set and vocabulary are minimal, at best, so it needs to be fairly simple.

  • jasonbar / about 15 years ago / 1

    I got the MP3 trigger set up this past week, but it often hangs up & needs a power reset to continue use.
    Sometimes I can go for minutes on end with no reset needed. Sometimes I can play only 3 or so MP3s before it no longer responds to buttons & needs a reset. It's inconsistent.
    I'm using just the 7 trigger buttons, and occasionally the rocker switch to go through other sounds in the root directory.
    I'm powering with 6VDC through the external power jack. This 6VDC comes from a DC-to-DC adapter (Radio Shack, I believe) in a car, being fed 12V from the car battery via the cigarette lighter. In benchtesting, I used a regulated power supply to power the DC-to-DC adapter & had the same results of occasional freezes.
    My solution was to wire a NC momentary switch in line with the ground power line & tap it whenever the board freezes.
    Any ideas on how to fix this problem?

    • robertsonics / about 15 years ago / 1

      Also... one more thing to try. Take your DC-to-DC adaptor out of the equation. If your bench supply is adjustable, just provide the MP3 Trigger with 6VDC directly. Or try using an AC-to-DC wall wart.

    • robertsonics / about 15 years ago / 1

      Sorry to hear your having problems. I have one here in my office with jumpers installed on all the TRIG inputs and it just plays music continuously, sometimes for days at a time, so what you are describing is definitely not normal.
      Does it always hang up just in between tracks, or ever while tracks are playing? Is the status light on, off, still functioning?
      If it were me, I'd first do a visual inspection of all solder joint under a magnifier. If you can't see anything obvious, then perhaps it's time to contact Sparkfun to inquire about a replacement.

  • wicks / about 15 years ago / 1

    I started work on a simple Arduino library to communicate with the MP3 Trigger. You can check out the source, fork it, and suggest updates on github:

  • teknoel / about 15 years ago / 1

    Thanks for the quick response! :)
    Looks like Apple iTunes is the source of the problem. iTunes may be adding some addition mp3 header info(?) to the mp3s when the application imports or converts audio tracks. I suspect it may be with the header information. The mp3s will still play, but with a bizarre delay.
    I was able to get the MP3 trigger working properly by creating mp3s with a dedicated sound conversion utility.
    MP3 trigger initiates playback almost instantaneously.

  • teknoel / about 15 years ago / 1

    I just tried one of these boards and inserted a valid microSD card.
    However queuing up mp3 tracks is taking just over 3 full seconds to start playing. I've tried two different brand cards, both of which are very fast cards. Lexar was one of the brands.
    I've also tried loading very short mp3's, about 5 seconds long, 128kbit data rate. The duration of the sound file doesn't seem to be a factor.
    Anyone have any ideas why this trigger isn't so speedy. It's not usable with a consistent 3 second delay for beginning playback.
    I was using the built-in shuttle controller to trigger the files? Is anyone know of delays associated with the shuttle controller?

    • johnyoyodyne / about 15 years ago / 1

      Really like this product. I am also experiencing a 3 second or so delay between tracks. I'm using the 1 gig micro sd card sold by SF COM-08163. I've tried using iTunes and a few other mp3 converters out there with same 3 second delay. Any suggestions? Thanks

      • robertsonics / about 15 years ago / 1

        If the green status LED is on, then the CPU is sending MP3 file data to the decoder. If there's no sound, then it must be sending either silence or non-audio data.
        My guess is that your encoding software is inserting non-audio information at the start of the file, such song title, artist info and maybe even album cover art. I'm no iTunes expert, but I suspect there's a way to suppress this.
        The alternative is to use an audio editor like Adobe Audition or Sony Soundforge to make the MP3 files. In my experience these apps encode just audio, without all the tags.

    • robertsonics / about 15 years ago / 1

      I responded to your message about this over on the MakerJam forum - I suggest we continue the discussion there. But this is certainly abnormal behavior - per previous discussion above, response time should be milliseconds. Are you certain that your microFlash card is formatted FAT16 (not FAT32) and that the MP3 tracks are located in the root directory? Does the green status LED come on immediately or does it also exhibit a delay?

  • pburgess / about 15 years ago / 1

    Neat stuff. What's the approximate latency between trigger input and beginning playback of the corresponding sound?

    • robertsonics / about 15 years ago / 1

      Input triggers are scanned at about 15msecs. If audio is not already playing then best case would be around 1 msec or less and worst case around 15 msec. If audio is already playing, then one can't simply start sending the new track data without producing noticeable distortion. In that case, the previous track has to be canceled and the decoder buffer flushed before sending the new track. I've never measured it but it probably adds another couple of msecs.
      I will tell you that it "feels" pretty instantaneous if you are pushing a button.

  • SeayWorld / about 15 years ago / 1

    Here's a thought. Could the baud rate be set by a text file on the flash card? Let's say 'baud.txt', and set the contents to the speed desired? If the file is absent, default the baud.

  • SeayWorld / about 15 years ago / 1

    I was able to find this programmer:
    Would this be appropriate?
    Does this board design have headers for the MiniProg?

  • SeayWorld / about 15 years ago / 1

    The BS1 from Parallax will support 2400 Baud. If you are going to make .hex files, I would do a 2400 & 9600.

  • robertsonics / about 15 years ago / 1

    The MP3 Trigger doesn't support user configurable baud rates, but it's a simple matter to create a build for whatever rate you need. The issue is re-programming the firmware. One option is to pick up a Cypress PSoC MiniProg and I can simply post the .hex files for different baud rates.
    What rates does the BS1 support?

  • SeayWorld / about 15 years ago / 1

    Would it be possible to Update the BIOS to allow for slower baud rates? I would like to use this with a BS1.

  • kurf / about 15 years ago / 1

    Wow, using PSOC in a project awesome.

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