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Description: It’s blue! It’s skinny! It’s the Arduino Pro! SparkFun’s minimal design approach to Arduino. This is a 5V Arduino running the 16MHz bootloader in a super-sleek form factor that will fit easily into your next small project.

Arduino Pro does not come with connectors populated so that you can solder in any connector or wire with any orientation you need. We recommend first time Arduino users start with the Uno R3. It’s a great board that will get you up and running quickly. The Arduino Pro series is meant for users that understand the limitations of this lack of connectors and USB off board.

To keep things affordable and low profile, we’ve chosen to make the DC power jack footprint available, but not to populate it. We recommend running the board with a LiPo battery for better portability. Also, to keep the cost low, we made changes like using all SMD components and switching to a two layer PCB.

This board connects directly to the FTDI Basic Breakout board and supports auto-reset. The Arduino Pro also works with the FTDI cable but the FTDI cable does not bring out the DTR pin so the auto-reset feature will not work. In this latest version of the Arduino Pro we’ve also moved the FTDI headers back just a skoach so that the pins don’t hang over the edge of the board. We’ve also populated it with a sturdier power selection switch.

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

Note: A portion of this sale is given back to Arduino LLC to help fund continued development of new tools and new IDE features.


  • ATmega328 running at 16MHz external resonator
  • USB connection off board
  • 5V regulator
  • Max 150mA output
  • Over current protected
  • Reverse polarity protected
  • DC input 5V up to 12V
  • Resettable fuse prevents damage to board in case of short
  • Power select switch acts as on/off switch

Dimensions: 2.1x2.05" (53.34x52.08mm)



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Customer Comments

  • We recommend running the board with a LiPo battery for better portability.

    But the minimum input voltage is 5V. LiPo’s are 4.1V at the very best. So how does the board work when switched to BATT mode, exactly?

    • The minimum input voltage in the Raw pin is 5V (actually probably a bit above that) because it goes through a 5V voltage regulator. But the minimum input voltage on VCC is a different story, and depends on the frequency the ATMega328 is running at. The datasheet for the ATMega328 has 3.3V listed outside the range for 16MHz, but we’ve seen it work just fine (the OpenLog actually runs with these values). I wouldn’t recommend much less than that, but 3.7V should be fine.

    • LiPos are 3.7V per cell nominally, 4.2V per cell fully charged, and 3.0V fully discharged. a 2S LiPo will be perfect for running this.

  • It took me a minute or two to figure out the buzzer so I posted a quick write up at TechSpin/Arduino Pro Buzzer.

    It seems the buzzer can be mounted either end up. I happened to mount mine with the words up and positive terminal down. Positive terminal connected to D4 and negative terminal connected to D5. With this configuration playing a tone on the buzzer is as simple as:

    void setup() 
      tone(4, 1000, 1000);
    void loop()  {  }

    Modifying the Arduino toneMelody example is as simple as adding a line and modifying two lines:

     #include "pitches.h"
    // notes in the melody:
    int melody[] = { NOTE_C4, NOTE_G3,NOTE_G3, NOTE_A3, NOTE_G3,0, NOTE_B3, NOTE_C4};
    // note durations: 4 = quarter note, 8 = eighth note, etc.:
    int noteDurations[] = { 4, 8, 8, 4,4,4,4,4 };
    void setup() {
    pinMode(5,OUTPUT); // <-- add this line
    // iterate over the notes of the melody:
    for (int thisNote = 0; thisNote < 8; thisNote++) {
    // to calculate the note duration, take one second 
    // divided by the note type.
    //e.g. quarter note = 1000 / 4, eighth note = 1000/8, etc.
    int noteDuration = 1000/noteDurations[thisNote];
    tone(4, melody[thisNote],noteDuration); // <-- edit this line
    // to distinguish the notes, set a minimum time between them.
    // the note's duration + 30% seems to work well:
    int pauseBetweenNotes = noteDuration * 1.30;
    // stop the tone playing:
      noTone(4); // <-- edit this line
    void loop() {  // no need to repeat the melody.
  • Does this board shut down with low voltage, in order to protect a lipo battery from complete discharge?

  • What’s the benefit of this board over the Pro Mini? The Pro Minis are still using the 328. I looked up a few of the specs and they were pretty much identical.

    • This board fits the standard Arduino shield footprint, which the Pro Minis are too tiny to fit. It’s a size/ease of use with other existing boards trade-off.

  • I thought you said backorders were allowed “There is a limit of two units for each product (per order) and back-orders are allowed” I wanted two of the 5Vs and one of the red boards but the sight wouldn’t ler me saying backorders are not allowed.

    • They’ve mentioned on the arudinoday comments that it’s a technical issue and are looking into it.

  • Wanted to buy one on sale, but guess what. No backorders available (unlike promised in e-mail) and sold out while fighting the damn credit card system so had to remove it then they sold out of another card I wanted. if something goes on sale, at least have enough on stock. SOld out in 3 minutes

    • They’ve mentioned on the arudinoday comments that it’s a technical issue and are looking into it.

  • I like Pro boards, but I sometime miss the 3v3 pins next to the 5v pin for my shield compatibility issues.
    If you have chance, please consider to change PCB 5V pattern routing going from FTDI con, as firstly 5V pin then to another VCC pin assingnd to 3v3 on UNOs. It may make easy to cut the 5V pattern and attach a 3v3 regulator on the bottom.

  • We need a Arduino Pro Mega 2560 board who looks similar like this one !

  • The free white circle, near the middle ?

  • These are great I have used 20 so far and just ordered 20 more. These have been extremely stable and reliable so far. In my application runs off 14 volts, so I use a voltage regulator to knock the voltage down to approx 7 volts to power the Pro. The project is completely enclosed and no problems so far. I’m driving a 16X2 LCD display with backlight and 5 LEDs. I notice they are running low, I hope they get more soon.

  • What is the Advantage of having a 16Mhz bootloader? How do I specify TX-1/RX-0 of the FTDI pins in my sketch? I’m currently working using D0 and D1 for TX/RX, but not with the FTDI TX/RX. Any help?

  • Can I use an Arduino Leonardo to programming this Arduino Pro ? I saw somewhere that I have to remove the ATmega chip to programming an Arduino Pro with another Arduino ans it’s quite difficult with a Leonardo …

  • I’m working on a project with the Arduino Pro that runs on solar and I want to keep the power needs as low as possible. Is the best way to power the pro by connecting the output of a 5V switching regulator to the 5V and Ground pins on 6 pin header (where you normally connect the FTDI cable). Is there a 500 ma current limit via that connection ?

  • The Pro is such a nice board to use! I used to always use my Mega 2560, but Pros are a lot cheaper to replace, and a 4xAA battery pack is just about the same size and the Pro can run off of 6 volts! Nice job Sparkfun!

  • If you add a DC power jack to this board then it makes it very difficult to fit the FTDI basic breakout board between the DC jack and the JST connector. I had to file down the JST slightly in order to get my FTDI breakout board to fit in between. Please consider increasing the space between the DC jack and the JST for the next batch of PCBs.

  • great.

  • Interesting - I had to replace the series resistors with 0 ohm on the TX/RX to get 115200 … R1 and R3.

    Worked great on the UNO smd and Rev 2 I have…

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