In the Summer of 2015, some drinking at a music show led to a discussion about putting leds and lasers on a pair of underwear. A bunch of us had a good laugh. Then I went home and built it. Who's laughing now? Turns out the entire audience.
OK, lasers not recommended for safety reasons, but hey, it's your underoos.
Great! Everything can be purchased off Adafruit. Here's the parts list: 1x Microcontroller. A Adafruit Gemma can barely fit the LSM303 code. An Arudino Pro Mini can fit the 9-DOF code with room left over. 1x Accelerometer. The code provided is for the Flora LSM303 or Flora 9-DOF. 4x Flora RGB Smart Neopixels 1x Adafruit Micro LiPo Charger 1x Conductive Thread Ribbon Cable (The original buttlasers used the now-discontinued 4-Channel Fabric Ribbon) 1x Pair of underwear or bicycle shorts Some fabric to create a small pouch with A needle and some thread
It is recommended that you AVOID the unshielded steel/conductive threads available on Adafruit for this project, and remove as little of the conductive thread's fabric as possible to minimize crossed wires/shorts (Ouch!)
For the Pro Mini: LED Pin is 7, Accelerometer is A4 (SDA) and A5 (SCL). For the Gemma: LED Pin is 1, Accelerometer is 0 (SDA) and 1 (SCL).
Pictures are enclosed of how the sewing works, The parts are centered when worn though they look off in the photo. Your intimates may differ, place the components with a mannueqin or someone wearing them.
Getting decent accelerometer readings is tough. It's recommended you stitch the pro or gemma as close to the person as possible. My chosen fabric comes from the pocket of a children's hooded sweathshirt. The LSM is hooked up to the back of the Arduino Pro Mini because it lined up the best.