Getting started with the Lilypad Arduino

Recently we had a visit from Dr. Leah Buechley, the inventor of the Lilypad Arduino, an electrical engineer, artist, entrepreneur, and more. Her visit came as we were already working hard at Arduino and is a great way to hopefully get more girls into coding. The Lilypad Arduino combines textiles and rapid prototyping with the Arduino. So, of course I wanted to make something to wear around school for that day. I give you, the new and improved Letterman Jacket – kinda…



I feel very comfortable with Arduino, so I decided to use some bits and pieces I hadn’t yet. I wanted to create a vest prototype that would only light up when you were moving. Here is a link to the code for the Arduino that I will be referencing. And a

Parts list:

  • 1 Lilypad Arduino
  • 1 Lilypad AA battery holder
  • 1 Accelerometer
  • 7 Blue LEDs
  • 8 White LEDs
  • Conductive Thread

Prototype 1:

I first started by mounting the LilyPad, accelerometer and some lights in the back. I went semi random fashion just to spread out the light. I didn’t bother hiding the thread, lilypad, or accelerometer as I was just using this for proof of concept.


The accelerometer(that little red circle above the Lilypad) is quite easy to use. It reads a voltage between 0 and 700 and then we map that to between 0 and 70. Play with the accelerometer to see how the orientation of the vest changes as you move it, and record those values. For me, the Z value was easiest to use in the fact that we bob up and down a bit when we step. And if you’re extra funky, you might have a serious bob.

It worked, but if I moved into a position that triggered it to move, it would keep lighting the LEDs over and over. I realized I needed to calculate a Delta/Difference value each loop and see if the difference between my previous presentation and the new one was enough to warrant as “motion activated” Make sure to use the abs function otherwise checking “less than” might be misleading.

The last bit of code was to make a random light show happen each time I moved. I love the function I wrote and don’t want to change it, but I also cannot quite figure out what it could be used for besides looking cool. Future plans would be to use a pulse sensor to light up the jacket with the heartbeat – useful for athletes, and coaches to monitor the heart rate.

Prototype 2:

I realized the back was cool but I rushed the design. So I decided to put a little lightshow on the front, and overlay a Steward Crest as a take on the old letterman jackets. I laid out the LEDs in parallel so they would all light the same. I had planned to use sheer fabric to disperse the light, but that proved very difficult to cut. So, Felt was the choice, although not my favorite. Worked like a charm.  It actually looked pretty awful. Even though I wanted a full lit crest, instead it was a crest with little dots of light. Totally professional quality right?

Problems and improvements:

The LEDs on the front don’t really disperse through the felt. I tried a piece of frosted plexiglass and still wasn’t very impressed.

  • It would be better to use LEDs with a large diffraction angle, edge lighting, or light strips.
  • Can’t use a reflective or traditional lighting for signs as the felt is not very thick.

The back could be lit to a student’s heartbeat, or other physiological indicator.

The light could be used in survival situations and integrated into clothing for search and rescue

The light could also be for firefighters trying to make their way through smoke filled rooms, line the doorway with them to indicate exits.


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