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Description: At SparkFun we use many Arduinos and we’re always looking for the simplest, most stable one. Each board is a bit different and no one board has everything we want, so we decided to make our own version that combines all our favorite features. The SparkFun RedBoard combines the simplicity of the UNO’s Optiboot bootloader (which is used in the Pro series), the stability of the FTDI (which we all missed after the Duemilanove was discontinued) and the R3 shield compatibility of the latest Arduino UNO R3.

The RedBoard can be programmed over a USB Mini-B cable using the Arduino IDE: Just plug in the board, select “Arduino UNO” from the board menu and you’re ready to upload code. RedBoard has all of the hardware peripherals you know and love: 14 Digital I/O pins with 6 PWM pins, 6 Analog Inputs, UART, SPI and external interrupts. We’ve also broken out the SDA, SCL and IOREF pins that showed up on the UNO R3, so the RedBoard will be compatible with future shields. This version adds an SMD ISP header for use with shields.

You can power the RedBoard over USB or through the barrel jack. The on-board power regulator can handle anything from 7 to 15VDC. Check out the related items below for a compatible wall-wart power supply.

Not sure which Arduino or Arduino-compatible board is right for you? Check out our Arduino Buying Guide!


  • ATmega328 microcontroller with Optiboot (UNO) Bootloader
  • USB Programming Facilitated by the Ubiquitous FTDI FT231X
  • Input voltage - 7-15V
  • 0-5V outputs with 3.3V compatible inputs
  • 14 Digital I/O Pins (6 PWM outputs)
  • 6 Analog Inputs
  • ISP Header
  • 32k Flash Memory
  • 16MHz Clock Speed
  • All SMD Construction
  • R3 Shield Compatible
  • Red PCB!


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Customer Comments

  • Since you’re using the SMD version of the atmega32 processor you really should have broken out the two extra A/D pins to connectors on the board. I know there is no way to add these without breaking shield compatibity, but you could put two pads somewhere so the user could access them. Much easier than trying to solder some #30 wire to the processor pins! I think there actually is an UNO clone somewhere that DOES bring these two pins out somehow.

  • Glad to see that you’ve populated the ISP header on this revision. The only possible improvement I can see now would be adding a 3.3V / 5V core logic selector switch. Anyway, nice work, SFE!

    • It is a nicer design and the logic level switch is a good idea. What I would like is it to use microUSB instead of mini and the reset button to be a right-angle board variety. That way a housing can let you plug in your cables and hit the reset easily.

      • USB 1.x/2.0 micro-B connectors are too delicate and annoying to align, in my humble opinion.

        • I guess it is one of those areas that is personal preference. I always find the micro to be pretty easy plus with so many things using it now I have a bunch of extra cables around and always one within reach of any spot I might be working on something.

          • with regards to delicate.. to many projects lately have been using smd versions of microusb connectors, and they rip of very easily, there are some that is almost throughole (for the casing, not the connector leads), which is more solid, so if everyone used connectors like that I guess one should be ok.

            • A trick I use when laying SMD-only connectors is to put a couple PTH holes at each side of the connector and then just run a bus wire up and over the part to “seatbelt” it down to the board. If the connector has a metal shell (such as µUSB), then you can solder the seatbelt to the shell itself. This makes it nearly impossible to rip an SMD connector off a board.

              • Even if they weren’t ripped off, micro USB is flawed in design. the connector itself wears out after repeated use. I’ve had it happen on a number of phones, after daily plug/unplug the male pins just stop making a connection. SparkFun made the right choice. This is a larger board, go with the larger, safer connector.

                • What part of the connector wears out? One of my favorite things about USB uB is that they moved the latching pins to the cable.

                  I had many a phone with miniB that wore out the latches internally, and nothing could fix that short of replacing the device or voiding my warranty.

                  I’ve had a couple uB cables wear out their latches on me, but a cable is cheap to replace compared to the device itself.

        • “micro-B connectors are too delicate and annoying to align…”

          No, they’re not. They’re being used by hundreds of millions of phones and such without problems. I second the micro-B request.

    • Thanks! Logic-level select is a really neat idea. That’s definitely something to think about.

    • You can always improve designs. Cost is often the only prohibiting factor.

      I’d like to see a UNO with a switching power supply like the Due has (LM2734Y). A linear regulator won’t allow the full output current at 12V input or higher. Indeed, it will already dissipate 1.5W at 12V input and 200mA, and become very hot, very likely even shutdown. The switcher will let you have up to 1A, even at 15V, without problems. Board real estate is not a problem (you need less cooling area), though the board would become a dollar more expensive. Well worth it, IMO

  • I would love to see you mark the SPI pins (SCK, MISO, MOSI) on the board as well

  • For this to be the ultimate board it really needs to have a crystal oscillator to control the timing of the microcontroller. For me, +/- 5% is just no where near accurate enough.

    • Most things that people are doing with Arduino do not rely on 20ppm precision timing where 100ppm would fail. For people who want long term precise timekeeping we suggest going with a TCXO (temperature compensation crystal oscillator) - but you would know if you needed that. — Lady Ada

      If you require precise timing, you should design your own boards.

  • SF, let us know on microprocessors whether the clock is crystal controlled, or resonator based. The difference between about +/- 2 seconds per day and about +/- 7 minutes a day can rule out some products for data acquisition or control when using internal time keeping. Sure, we could get a WWV receiver or buy an atomic clock (or even an RTC from you guys), but for about 20 cents difference or less and no hassle getting a crystal in the product works well for very many things.

  • The bootloader appear to be affected by what is in the EEPROM memory. With certain values it does not execute the sketch. What kind of bootloader is reading the EEPROM? Do you have the sources for the bootloader used in the RedBoard?

  • I have an idea for a new version of the RedBoard, one that has a connector for a Lithium-ion battery,a on-board charging circuit, voltage booster regulator to supply 5 volts to the board and a on/off switch.

  • It would be really nice if these had some silkscreening that reminded you what kind of arduino board to select in the ide. Something like “arduino uno r3 compatible,” or “board type: arduino uno.” It would really help beginners and people who get one as part of a class and then months later want to put it to use. That’s the only reason I can’t recommend the inventor’s kit to newbies anymore.

    • I like the idea, I just don’t know if we can do it. Because its not an official Arduino board there are limits to what we can put on the board, but I’ll pass on the suggestion.

    • In this case I would suggest a handy dandy label maker!

  • These dont look like sale prices for arduino day, where are the sale prices?

  • What about the most important feature you left out – using a removable DIP microcontroller so you can program your chip and then pull it off the board and use it directly in your project.

  • I’ve always wondered why the Arduino doesn’t have a SMPS instead of the 1117. Yes, I know: cost and possible certification issues. But when you have a 12V supply for the board with a linear regulator there’s no way you can draw 800 mA from the 5V; it would cause the 1117 to dissipate more than 5W, causing it to light up in the dark…

  • Hi guys… what will happen to the red board if i press the rest button?

  • The board is quite nice, but the power light is glaring, and the TX/RX LED labels are backwards (at least on the version of the board I got). They are correct in some illustrations on the website, so they clearly got mixed up in production somehow.

  • Hello I am using your Red board for a temperature sensor test, using lm34 sensor….I was wandering if you have a breakout board, what connects to the input and output pins of the red board so it can be used for applications besides using with the breadboard.? Thanks

    • I’m not quite sure what you are asking since you can use this without a breadboard as is, but I think that the Protoshield may solve your problem.

      • Hi there, sorry I was multitasking earlier…I meant to say, I am done prototyping, now I want to use the red board to control the temperature for real application and I want to hard wire it, the protoshield might just do the trick for me. For my project I want to use c-grid connector where I can hard wire using long cables….do you guys sell the protoboard by itself? Also will I still run into issue of mounting the protoshield board on top of the red board or arduino uno board because of the USB and 5vdc plug?

        Thanks SG

  • Are there any differences between the SPI implementation on this board, the last RedBoard, and the UNO? Has any one tried this board with a Nordic nRF24L01+ based ISM transceiver interfaced via SPI? I have 2 UNO’s communicating successfully using the RF24 library from with Addicore nRF24L01+ modules. My RedBoard (previous revision) will not play with either of the UNO’s using the Nordic modules. I borrowed a buddy’s Redboard (also previous revision) and it would not play either. Using the GettingStarted sketch from the RF24 library, the radio would return valid status. It would generate valid traffic (received by an UNO) when in TX mode. It failed to receive ping responses in TX mode as well as failing to see pings when in RX mode. I tested this with both the ISP headers and pins 10 - 13, on all 4 boards.

  • Is there anyway to turn of the “ON” LED indicator on the RedBoard? it’s really glaring and blinding me.

  • It looks to me like the schematic diagram has the power jack wired up wrong. The symbol for the power jack has the connections for the ground connection and the switch contact reversed. The barrel contact should be grounded and the switch that is NC (when the plug isn’t inserted) should go to the FET gate.

  • will this work on windows 7 64 bit OS? i have an Arduino Uno and while uploading the sketch i always get the avr dude error ?

    • Yes, but the Uno should work too. Most of the machines at Sparkfun are Windows 7 64-bit and we have no problems with either the Redboard or the Uno. If you are having problems make sure the drivers are installed correctly and if you are still having problems email

  • Red Borad not working on a MAC -running Mavericks? try this:

    Good luck

  • I’m designing a shield for use with your board and noticed that when powered by USB only, I am getting power on the Vin pin. I looked at your schematic but your schematic is missing some components such as the LMV358. Can you update your schematic please.

    • If you have an op LMV358 on there, you probably have the older version. Here is the schematic for that board.

      • Thanks Jimb0 but unfortunately that schematic is also not correct. It does not show Vin connected to the power jack via the diode.

        Neither schematic explain why I have USB power on the Vin pin when USB is the only source of power unless it is feeding back (from OUT to IN) through the LM1117.

  • Hey guys,

    Thought I would point out that there is an error in the schematic with regards to how you have connected the DC barrel jack pins.

    Ground should be connected to pin 2 of the barrel jack rather than pin 3 as the schematic currently shows.

    With the current configuration, when the connector is inserted, the barrel is no longer connected to ground which means that the circuit has no reference. The design would only work with USB power.

  • Does anyone know if I can use the RedBoard with GRBL ? I’ve read that only works with Arduino Uno/Duemillanove. Tried myself with a Leonardo with no luck.

    • If it works on the Uno/Duemillanove it should work fine on the Redboard. The redboard uses the same microcontroller (ATMega328) and has the same bootloader as the Uno. The Leonardo uses a different microcontroller (ATMega32U4) which is probably why its not working.

  • have a RedBoard that someone from Sparkfun gave my son at a conference in Austin. I can’t upload any sketches to it.

    I’ve got serial port connectivity to it on both OS X and FreeBSD, at least, I have connectivity enough to make the ‘TX’ LED light with each keystroke.

    but if I try to use the Arduino software (using the blink example), I get:

    “Binary sketch size: 1,084 bytes (of a 32,256 byte maximum) avrdude: stk500_recv(): programmer is not responding”

    I’ve never seen a response (of any type) from the board. I would think that the boot loader (if present) would respond to, say, a simple carriage return.

    From ‘cu’, I’ve tried the following baud rates: 4800, 9600, 19200, 38400, 57600, 115200.

    None have succeeded.

    I believe I have the correct drivers. When the RedBoard is plugged in, dmesg reports:

    AppleUSBFTDI, fInBufPool,kMaxInBufPool 8,64 0 [Level 5] [] [ AppleUSBFTDI] [ 0x403] [ 0x6001] [ YES] AppleUSBFTDI: Version number - 1.0.1b10, Input buffers 8, Output buffers 16

    and I get two device entries: /dev/tty.usbserial-AM01VDPE /dev/cu.usbserial-AM01VDPE

    both are mode 666 (crw-rw-rw), so it’s not a permissions problem.

    Powering the board on blinks the blue LED (marked ‘13’) three times.


    • I had trouble too, using MacOS Mavericks. I found experimentally that hitting the reset button 3 times about a second apart after hitting the “load” function got the reset to hit at the right time and download the board, but that got really tedious really fast.

      Although MacOS comes with FTDI drivers written by Apple, they don’t seem to control the modem-control lines, or if they do, not the same way the Arduino SDK and bootloader expect. I downloaded the latest MacOS drivers from the FTDI site and it works great now. I just now searched and found this, which tells how to do it:

      On a related front, I’ve had 2 MacOS crashes while working with Arduino, the only ones I’ve ever had in my entire history with MacOS X except when my hardware was dying. (Other people have had this too, e.g., see ) My hypothesis is that it’s from a USB-connected Arduino running a sketch spewing data but with no terminal window running, exercising a driver bug or a bug in the USB serial port handling, but I don’t know (it happened both before and after my driver upgrade, so I lean toward it being in USB code). Since I first had that suspicion, I’ve always started a terminal window as soon as a sketch is loaded, and haven’t had another crash, but YMMV.

    • can probably help you better than the comments section can on this one.

  • PLEASE (if possible) change your power plugs and USB to thru hole!! the students I work with (6-12th) are destroying them when they fall off of tables. Especially the young kids.

    • Have you tried using these?

    • Actually, there is a small change that SparkFun can make without going to through hole that can go a LONG ways to solving this problem. Check with your PCB manufacturing house to find out what the smallest via is that will not incur extra charges, then make sure there are two or three vias of this size on each of the “mechanical” pads for things like power sockets and USB sockets, as well as any surface mount pad that you expect the user to solder to. Some copper area around the “mechanical strength vias” that is on what is traditionally called the “solder side” (as opposed to “component side”) also helps.

      Note: this trick also helps avoid problems with the occasional board that sneaks through with bad adhesion of the copper to the substrate.

      IMHO (based on many years in electronics), this is something worth making “standard operating procedure” for all your boards.

      • wow, that is an good idea, the boards that have torn of connectors have had the copper ripped off, with some vias that should probably stitch it together better, hm..

  • Someone care to explain how the reliability of FTDI differs from the serial programming implementation on the UNO? And for that matter, how is it preferable to ISP? I’ve noticed lots of the lower-end boards featuring only FTDI connections for programming and no ISP breakout– isn’t ISP supported natively on every AVR device? What’s the rationale here?

    • I’d say both the Uno’s custom-firmware’d ATmega16U2 and the FTDI on the RedBoard are equally reliable at this point. We’ve grown quite fond of the FTDI over the past few years because of how solid a chip it is. That, and the fact that it fits better into our manufacturing process (only one chip to program), are our main reasons for using it on the RedBoard.

      Actually, one of the big changes in this revision was to populate that 2x3-pin ISP header. You can certainly program the RedBoard using an AVR programmer – there’s even an option in Arduino to upload your program via ISP – but serial programming is generally easier (especially for a beginner who doesn’t have an AVR ISP readily available [or a lazy engineer, who’s AVR ISP is all the way across the room]).

      • Thanks for the reply. A USBASP or similar can be got for $5, same as a FTDI cable, and can be used from the arduino IDE with a simple menu selection, so I’m still not seeing the benefit– of course this is a moot point here, just been wondering why so many cheap board have a FTDI interface but no breakout for the ISP header.

        • Keep in mind that the upload from the Arduino IDE wasn’t introduced until at least version 1.0. So for years people didn’t have that option. Also, all AVR based Arduinos, as well as all of our Arduino clones have the ISP header on them if you want to use it (a few that are too small don’t have the 2x3 header but do have the pins broken out). We actually use the ISP header to put the bootloader on all of our boards.

    • I don’t know what advantage they’re implying exists using the chip from FTDI vs a little AVR emulating the USB-Serial niche. But the advantage of using a separate chip from the main AVR is that your USB connection doesn’t reset along with the MCU. It can be annoying when its serial port jumps from /dev/ttyACM0 to /dev/ttyACM1.

    • I don’t think it’s (FTDI) a matter of reliability or any real functionality improvement, but rather one of convenience. Many electronics newcomers won’t have a serial programmer, and want only something cheap and easy to use.

      I’m pretty heavily invested in Microchip PIC programming (8 & 32 bit, don’t care for the 16 bitters), but I think I’m going to get one of these for my kids to tinker with. Pretty neat piece of kit.

  • I see the Redboard has joined the FT231X club. What is the difference between this and the FT232R? Just a newer/cheaper part?

Customer Reviews

4.6 out of 5

Based on 25 ratings:

5 star
4 star
3 star
2 star
1 star

1 of 1 found this helpful:

Good as usual

My only complaint so far is the obnoxiously bright LEDs that are on this board. No more stealth with this thing. Otherwise its an amazing product as usual from SFE!

1 of 1 found this helpful:

Good price for Uno-compatible

The redboards are nice Uno-compatible boards, except for one problem: recent versions of Mac OS X have broken (or omitted) the FTDI drivers. It works find on my old Mac 10.6.8 OS, but students have been having trouble on newer machines. Since the main reason for choosing an old, slow processor like an Arduino compatible was for ease of use by beginners, this broken-driver problem is very irritating.

Sparkfun should test post instructions on the Redboard site for fixing the Mac OS driver problem (there are a few scattered mentions on the Arduino forums, and the FTDI page linked to by Sparkfun is not straight-forward enough for novices).

1 of 1 found this helpful:

Love em

I also call them ‘ol trusty. SparkFuns one of the few companies that kicks money back to Arduino, and being possibly the last company still manufacturing in North America it’s worth supporting.

9 of 9 found this helpful:

great Arduino UNO compatible board

I own several of these, some of them different revisions of the board. They all work great, and the price is really good. Always check what the currently shipping boards look like though.. the USB connector on these are USB Mini-B which differs from the Arduino UNO R3’s normal USB ‘B’ connector. (i.e. be sure to have the right USB data cable on hand to program the board)

I believe the earlier versions of this board did not break out the pins above D13 (SCL/SDA/AREF/GND) as female headers, but the more recent ones do, so that’s good news for any shields that may have relied on those header connections.

I’ve not encountered any problems programming these with the Arduino IDE as long as you select the correct board type in the software.

I like the nearly perfectly smooth back of the board that results from the surface-mount components, too. I feel like I don’t need to worry as much about rubber feet or standoffs beneath the board to avoid accidentally shorting something.

Buy a few for the kids! My kids love ‘em and are now constantly asking me to buy them some Picoboards..

3 of 3 found this helpful:

Proud of this board

What can you not love about this board, it gets the job done and supports out favorite company.

3 of 3 found this helpful:

Great board!

Only complaint I have is that it uses a mini-USB instead of micro-USB, because I have a ton of micro-USB cables lying around. I must have missed that in the product description.

Fortunately, I found an old cable in my workshop and was able to program it without running out to grab one.

1 of 1 found this helpful:

This is a great Arduino alternative.

I bought this about 2 weeks ago and have been developing on it just about everyday since. It’s 100% compatible with the Uno and haven’t had any issues with its functionality. Its $5 cheaper and just as good.

Only change i would make is the on-board resistors seem too bright. A bigger resistor to make those a little duller would make this perfect.

Works great.

I have tested many different operations with the new RedBoard and it works just fine.

very good

Does what stated to do. Great support

Great Board, Well Made

Just starting out with programming and prototyping with Arduino and this board along with the starter kit has been great.


This is the 3rd redboard for me. Seems to function well. Saw this as a reasonable compromise between a real uno and another clone that may not be as stable as the redboard.

Everthing working, nothing to complain

I had no problems using the board with the board using arduino so far and everything worked out of the box. I can definitely recommend this for less experienced people as it is inexpensive and the arduino environment will support it without any configuration effort other than selecting the correct virtual com port.

SparkFun RedBoard

works great and a very good value!

Great Board! Needs More Support

The board itself is perfect. It would be nice to have Fritzing part, more tutorials, etc.

Just plain works!

I’ve been slowly getting into the Arduino world and looking for an affordable way to replace/add to the 15 year old basic stamps in my classroom (I still use one of the Board of Education that were given away the day their website opened). Sparkfun was great about working with me to get the educator discount and set up purchase order capability. The price for the redboard is great and it works flawlessly with the Arduino IDE. I especially like that it uses the common USB A to mini B cable. The only drawback is that one cannot replace the Atmega328 as it’s a surface mount on the Redboard. Bought one for myself and soon after ordered 10 more for the class.

A very nice thing

Works easily and as advertized

Best thing I ever owned!!

works just like the uno! Cheaper and has a mini usb!!! Thanks Sparkfun! :)

Works great, no problems

Using it as a weather station, works great, no problems.

Great Value

Less time soldering/wiring/debugging and more time making/coding useful projects.

Great board for arduino inventors

There are no programs that I have put through it that have had issues. Love this board. Good mix of quality and price point. Highly Recommended.

I have several!

I own three or four of these and I really like them! A little cheaper (in price) than a standard Arduino and still does the same thing. I’m mostly using them in turnkey projects, like CNC control with GRBL and my custom GRBL interface shield. A good no-thrills clone that does it’s job well.

Works as expected

The board acts exactly like an Arduino-brand board. I like the fact that the smaller USB connector was used, but I think it would be even better with a micro USB connector.

VERY nice thing to get started with!

I heard about Arduino from my uncle when I discussed about my interest in electronics and especially in controlling stuff. Then I did some digging and found your awesome page with lots of good stuff there and saw the Inventors kit. The collection of motors and servos and interesting sensor made me grab my wallet and order it immediately. Once it arrived, I haven’t done nearly anything else than programmed it. So, it was a really good purchase and got me even more interested in electronics ! You have also lots of other good stuff to buy. If I had the change I’d buy all of them but, you know, money…

P.S. The emails You send have good news about all the new stuff and I would also raise a thumb to your tutorials and product reviews!