LilyPad Arduino USB - ATmega32U4 Board

The LilyPad Simple just got a whole lot... simpler. We've updated the Simple board to create the LilyPad USB by replacing the classic ATMega328 with the new ATMega32U4. Not only does that mean that it's running a variation of the latest and greatest bootloader, but it also means no more FTDI Basic! The only extra piece of hardware you need to program the LilyPad USB is a micro-USB cable, since the new IC has built-in USB support. The LilyPad USB is also officially supported in the Arduino IDE as of version 1.0.2!

Just like the LilyPad Simple, this board features a JST socket so you can directly connect a Li-Po battery for power and an on-board power switch so you can turn it off when you're not feeling particularly blinky. These boards were designed to streamline your next sewable project by keeping things simple and giving you more room to work while eliminating the need to sew a power supply. The LiPo battery is even rechargeable through the board, no more special external LiPo chargers required!

LilyPad is a wearable e-textile technology developed by Leah Buechley and cooperatively designed by Leah and SparkFun. Each LilyPad was creatively designed to have large connecting pads to allow them to be sewn into clothing. Various input, output, power, and sensor boards are available. They're even washable!

Note: A portion of this sale is given back to Dr. Leah Buechley for continued development and education of e-textiles and also to Arduino LLC to help fund continued development of new tools and new IDE features.

Note: See the GitHub link below for support with the Arduino IDE.

  • 50mm outer diameter
  • Thin 0.8mm PCB

LilyPad Arduino USB - ATmega32U4 Board Product Help and Resources

Pro Micro & Fio V3 Hookup Guide

November 8, 2013

An overview of the Atmega32U4-based Pro Micro and FioV3, how to install it, and how to use it with Arduino.

Core Skill: DIY

Whether it's for assembling a kit, hacking an enclosure, or creating your own parts; the DIY skill is all about knowing how to use tools and the techniques associated with them.


Skill Level: Noob - Basic assembly is required. You may need to provide your own basic tools like a screwdriver, hammer or scissors. Power tools or custom parts are not required. Instructions will be included and easy to follow. Sewing may be required, but only with included patterns.
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Core Skill: Programming

If a board needs code or communicates somehow, you're going to need to know how to program or interface with it. The programming skill is all about communication and code.

2 Programming

Skill Level: Rookie - You will need a better fundamental understand of what code is, and how it works. You will be using beginner-level software and development tools like Arduino. You will be dealing directly with code, but numerous examples and libraries are available. Sensors or shields will communicate with serial or TTL.
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Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

1 Electrical Prototyping

Skill Level: Noob - You don't need to reference a datasheet, but you will need to know basic power requirements.
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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.

  • clothbot / about 12 years ago / 2

    Looking at the schematic, you should also mention the on-board MCP73831 for USB-charging the Li-Po battery. Very handy feature, not having to charge off-board.

    • Maxturbo211 / about 11 years ago * / 1

      I was wondering why the on/off switch said on/chg

      any simple way to bridge that charging circuit into say, some worn solar cells? those +/- on the datasheet don't seem to make it to the charging circuitry.

    • Good eye! Yup, just like the Simple, this board includes a charging circuit. I added that to the description.

  • I just bought this product but my computer cant detect it when I connect it to the USB. What could be the problem?

  • KPRoche / about 10 years ago / 1

    I've just finished a small project with this and really like the result. I especially appreciated the integrated charging circuit and micro-usb, as the project was being sewn into and onto a silk necktie. That is the reason I chose this board over one of the other LilyPad Arduinos.

    I do wish, however, that I had access to a few more digital IO lines. I could not quite tell from the photos if there were traces in the circuit board that bring any of those lines out but don't extend to the edge of the card? If there are, I have the skills and tools to solder leads; I just don't want to try to solder directly to legs of the processor itself.

    • KPRoche / about 10 years ago / 1

      After working at this a bit, I realized the odds of my successfully soldering leads to the unused digital IO pins was pretty much zero.

      I did, however, realize that there were two more analog pins that aren't brought out, so I could use one of those for my randomseed call, and that the LED on the board for digital pin 13 has a very nice large solder pad available.

      This means you can actually get 10 digital signals out, if you use digitalWrite on the A2,A3,A4,A5 outputs, and solder a lead to the pin 13 LED pad nearest the processor.

  • Member #544215 / about 10 years ago / 1

    Nice alternative to the Fio if you're using RF other than XBee.

  • Member #415133 / about 10 years ago / 1

    Question: Does this board have 5v on it while using a LiPo batery ? I want to use it to control 5 neosticks. Are there any lilypads arduinos with 5v?

    • M-Short / about 10 years ago / 1

      The issue isn't with the Lilypad boards, but with the battery. All the Lilypad boards will run at 5V, but a single cell Lipo will only output between 3.7V and 4.2V. Because the Lilypad boards will also run at this voltage we don't have any boards that boost the voltage (that tends to waste energy and cost money to do). You can use an external voltage booster, or find a way to provide 5V to the board. Also, make sure the Neosticks can't run at 4.2, devices usually have a range, and if only one voltage is listed its often the most popular voltage in that range.

      • Member #415133 / about 10 years ago / 1

        Oh. I meant NeoPixel sticks... 4 or 5 of them. I think Im ok with it. This and a 1000mAh LiPo battery should be enough to make me a blinky thing. Thanks for the help!

  • Member #492678 / about 10 years ago / 1

    Does anybody know if the LilyPad Arduino USB can support a display? If yes, what kind of display and how? (what kind of connection and how to program it) I have attached the LilyPad Arduino USB with a bluetooth serial port module in order to send some dummy readings to an android app via bluetooth and I would like to have these readings shown on a display as well. Thank you

    • SFUptownMaker / about 10 years ago * / 1

      Your best bet is probably some kind of serial LCD; we carry a variety of those. You can use a software serial port on one of the unused pins.

  • Does anyone know the charge rate on for the on-board MCP73831?

    • Kamiquasi / about 10 years ago / 1

      The charge current depends on Rprog, across the prog and Vss pins, which according to the schematic is 10kOhm, which according to the formula and graph should be about 100mA. There is another graph that shows what happens if you go half a volt under the USB 5V for exactly a 10kOhm Rprog, but all that does is make the charge current 101mA.

  • Member #474775 / about 10 years ago / 1

    I'm a total newbie and need some guidance! To use this board, I would also need to purchase a LiPo battery correct?

    • SFUptownMaker / about 10 years ago / 1

      That's the easiest solution, yes. Note that this board comes with a built-in charger for it; all you need to charge is a standard late-model cell phone charger (with a USB microB connector).

  • I'm having an issue with this board with relation to noisy electret mic (op-amp) readings? and wondering if anyone else is experiencing this and knows what a solution is.

    I attach the mic to any of the analog inputs in the Lilypad Arduino USB. I get almost near constant 1024 readings f it. Funny thing, it does this also with a brand new arduino lilypad as well.

    • I had the same problem even with the Adafruit Mic Amp. However I was able to solve the problem on the Adafruit Mic by putting 4.7uf decoupling capacitor on the batteries terminals.

  • Will this revision will work with a BlueSMiRF modem ( According to the comments, the previous revision ( didn't supply enough current.

  • Member #43061 / about 11 years ago / 1

    I purchased the LilyPad and Li-Po 2000mA battery The battery terminals are reversed. I have a few SparkFun USB Li-Po single chargers and the (+) is on the left, looking from top. All the JST cables I purchased are left (+). On the LilyPad, the (+) is on the right. Since I was planning on interchanging battery to different devices, it would be difficult to have to swap the power leads. Actually it would be logical to have specifications of pin 1 (left) be always (+) for all your products, keeping it consistent. It would keep people from letting the magic smoke out.

    • SFUptownMaker / about 11 years ago / 1

      I see where you're confused, because the pads on the design are the reverse of the battery connection, but the battery pinout on here is standard to all SparkFun products. The layout of the pads around the edge is meant to be consistent with the LilyPad Simple board.

      If you swap your battery connector, you'll fry the board. Please don't do that.

      • Josh C / about 10 years ago / 1

        I was puzzled by the same thing; this is really confusing! I don't see how you could expect customers to think that the ground wire should go into the connector where it's clearly marked "+". But like 43061, I checked voltage while under USB power, and sure enough, the battery terminal is reverse of the markings.

      • Member #43061 / about 11 years ago / 1

        Thanks for the clarification. I ohmed the ground out just to be safe :) Bad experiences with other vendors.... :)

  • Member #489715 / about 11 years ago / 1

    So i have a basic program I downloaded to my Lilypad Arduino USB to test the LEDs i had attached and it work fine. But now when i try to connect it back to the computer to download a new code it says the USB device is not recognized. I cant figure out what to do. PLEASE HELP!

    • Double check that your drivers are installed correctly. Also double check that you aren't accidentally shorting out the board anywhere with your LEDs attached. If you are still having trouble after that, please contact tech support and they should be able to assist you further.

  • Member #142301 / about 11 years ago / 1

    Hi Is there an error in the schematic for this board? It shows UVCC not connected to anything and UCAP connected to 3.3v. Is this correct? Jon

  • Member #461113 / about 11 years ago / 1

    I'm using this board and attach them to 20 lilypad Leds, with pin 2,10,11,A2,A3, and A5 as the output. I want to use the function "fade" and made them fade all together at the same time. But somehow it can't. only pin 10,11 Leds are able to fade, the rest just blink. I don't understand what's wrong, is it the board or the LEDs?

  • Member #463960 / about 11 years ago / 1

    Hello Sir, I was making a musical pillow given on the website And I am not able to understand, which lily pad arduino kit should I choose. Can u help me wth this. The other option of the kit is : What is the difference between the two?

    • The other one you linked to is just for blinking LEDs, it can't be programmed. For the tutorial you mention, you could either use this one, or the lilypad simple. either of those two will work.

  • Member #459839 / about 11 years ago / 1

    I want to connect this Arduino to a LCD screen. I am thinking the easiest way to do that would be via a serial connection: to a serial enabled screen: I have used other Arduino and screens, but am a little hesitant here because there are so few I/O ports. I can't seem to find a good tutorial where folks have used lilypads and LCDs. Anybody have some experience?

  • Member #436493 / about 11 years ago / 1

    My computer is not showing this board in "Device Manager" (Windows XP and 7). Is it because it doesn't have the bootloader ? or do I need to install any drivers for it ?

    • M-Short / about 11 years ago / 1

      If its not showing up at all it might be a bad USB connector. Contrary to the internet is rarely a problem with the bootloader, and you do need to be able to see the board before you can install the drivers. If you are still having problems email

  • EFFALO / about 11 years ago / 1

    how does one access the pins not labelled on the metal tabs? e.g digital pins 1, 4-8, etc

    • Kamiquasi / about 11 years ago / 1

      It doesn't look like they're broken out in any way, so you'd have to very, very carefully solder to the pins on the board - which tends to be less than desirable for e-textiles work. Of course every pin could be broken out, but imagine how big the board would have to be :)

  • VirtualBoxer / about 12 years ago / 1

    I might call this the Leonardo LilyPad.

  • VirtualBoxer / about 12 years ago / 1

    It would be much better if there were a version that broke out every pin.

  • andy4us / about 12 years ago / 1

    whats a good lipo to pair with this ?

    • andy4us / about 12 years ago / 1

      OK, is this a good match ? Since this board has the charging circuit etc, it would be good if you added some to either the description, or the staff picks. Also, the Polymer Lithium Ion Battery title is a little confusing, since "everyone" refers to them as LiPo's, so I was unsure if that was a lipo, or a lithium Ion battery. It was only the Datasheet link that gave it away. I suggest changing the title to Lithium Polymer battery (LiPo).

      • SFUptownMaker / about 12 years ago / 1

        That's a good choice for a battery- it's not too big, not too small. Charge time for that one with the LilyPad Arduino USB will be on the order of six hours.

  • Member #384959 / about 12 years ago / 1

    How do I purchase the new ATMega32U4 Caterina Bootloader chip for my own custom LilyPad prototype board?

    • We sell the TQFP package of this chip here:

      But we don't carry one with the bootloader pre-installed. You'll need to break out the ICSP lines on your prototype and use an AVR programmer (like PGM-09825) to burn the bootloader. This can be done through the Arduino IDE. Simply check the device datasheet to find which pins are used for in-system programming, connect them to the pocket AVR programmer and select "burn bootloader" in the Arduino IDE with "USB tiny" as the programmer.

      Hope that helps!

  • Wow. This one has a lot of functionality.

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