LilyPad Development Board Hookup Guide

Contributors: jimblom, Gella
Favorited Favorite 3

Technical Notes

If you’ve already programmed Arduino for a while, read on for some additional notes about the LilyPad Development Board. It’s very similar to other Arduinos, but has some special features and limitations you’ll want to know about.

Pin Numbering

Below is a list of the LilyPad Arduino Simple I/O pins and each function.


  • n = digital pin
  • ~n = PWM-capable pin
  • n, serial = hardware serial pin for either UART, I2C, or SPI
  • An = analog-capable pin
  • (n) = internal pin (not connected to sew tab)
  • [n] = internal pin (available on an exposed via)
  • {n} = internal pin (available on male header pin)
Function Digital Analog
Rx-I {0}, RX
Tx-O {1}, TX
Slide Switch (2)
Vibe Board (~3)
White LED ~5
White LED ~6
Buzzer (7)
RGB LED - Red ~9
RGB LED - Blue ~10, SS
RGB LED - Green 11, MOSI
[12], MISO
Built-in Green LED [13], SCK
Temperature Sensor (15) (A1)
White LED 16 A2
White LED 17 A3
White LED 18 A4, SDA
Momentary Push Button 19 A5, SCL
Light Sensor (A6)

Using a LiPo Battery and Battery Charging

SparkFun sells a number of LiPo batteries compatible with this board. If you are new to the LilyPad system, we recommend the E-Textiles Battery. If you're supplying your own battery, use a single-cell (3.7V) LiPo battery with a JST connector.

Batteries with larger capacities (measured as amp-hours or Ah) will run the board longer before needing recharging. How long will depend on how many LEDs your program turns on, etc. If you're just running a few LEDs, you can expect the board to run about 5 hours for every 100mAh of battery capacity.

Charge Rate

To recharge an attached battery, plug the board into a USB power source. While the battery is charging, the "CHG" LED will illuminate. When the battery is fully charged the LED will turn off. The default charge current is set to 100mA, so a 100mAh battery will recharge in one hour, a 1000mAh battery in 10 hours, etc. Since the board is set to charge at a rate of 100mA, we do not recommend connecting a lower capacity LiPo battery (i.e. 40mAh LiPo battery) to charge.

Connecting a LiPo  Battery to the LilyPad ProtoSnap Plus

An example of inserting a LiPo battery into a JST connector on a different LilyPad board.

It is safe to leave a LiPo battery attached to the board permanently, even with USB power applied. The battery will not be overcharged.

Notes on Washing LilyPad Projects

Removing the LiPo Battery

The battery connector can be tight; to remove a battery never pull on the wires. Use a pair of needle nose pliers or cutters to gently hold pull the plug out of the connector.

Below is an image of the a LiPo battery being removed from a different LilyPad with needle nose pliers.

Removing a LiPo Battery from a LilyPad Board

An example of how to remove a LiPo battery from the JST connector on a different LilyPad board.