Light Up with Gemma. Creating a flashing wearable using Adafruit’s Gemma and Neopixels. Education Resource here
Kit Ingredients: Sewing
- GEMMA (you could use a trinket)
- NeoPixels (this project uses 7)
- Conductive Thread
- Sewing Needles
- Small Alligator Clip Test Leads
- USB cable
- 2 x CR2032 coin cell batteries
- Coin cell battery holder with JST connector and on/off switch
- or Lipo battery and charger
Soldering see here for instructions
- Soldering Iron
- Hook-Up or Equipment wire (0.2)
First bit- What is a Gemma?
“Get started with Adafruit GEMMA with this lovely starter kit! Included is everything you need to make a basic project. There’s a GEMMA board, four sewable bright RGB pixels, a battery holder and batteries, 2-ply conductive thread, alligator clips to help you test out your circuit, and a USB cable for programming GEMMA.” Adafruit.com
The Gemma does not have a Serial port connection for debugging so the serial port monitor will not be able to send/receive data. Unlike the Flora, the Gemma must be connected to a computer via a USB cable.
- Set Up IDE (if not done already)
- Check your kits has everything
- If new to sewing, practice on some scrap material first.
- To upload your code (sketch)
- Don’t press-and-hold the reset button(small black button near D0 pin), be sure to press-and-release! Once pressed the onboard LED will pulse for 10 seconds. During these 10 seconds upload your code.
- Power up and GO!
What Can we MAKE?
How many Neopixels can the Gemma Run?
Yes! Gemma was designed to drive short segments of NeoPixels. There is enough RAM on the attiny85 to drive 100 pixels, but depending on program RAM usage you may have to scale back to 60 or 40. Then you have to think about Power.
Lets Get Started
Now it’s time to say “hello, world” to your new Gemma with the basic Blink sketch.
Step 1: Upload Blinky sketch to your Gemma
- Launch arduino application
- Open blinky (copy and past from here)
- Click the tick icon to verify the code
- Press the button on the Gemma to enable the board to receive the code.
- Click the arrow icon to upload the code to the Gemma
- The RED led onboard the Gemma should blink.
WHY do Blinky? to test that your board is functioning properly and that you have successfully verified and upload a sketch onto your Gemma. This step can be skipped if you have already worked with Gemma. Step one helps with understanding of debugging should any issues arise.
Step 2: Stitch a NEOPIXEL
Depending on how many neopixels you have connect the first one to the Gemma using ground, D1 and Vout. Ensure that the data line (from D1) it tied off to the first arrow on the neopixel. Test the circuit using headdress code modifying the number ‘7’ to 1. This tells the code that there is only 1 neopixel in the strip. modify this number to the final number of neopixels in your project.
The Power and the Ground thread can be a continue piece of the thread. Ensure that the connection at each point is secure. This can be achieved by stitching a few times around each connection hole. The –> must be pointing away from the GEMMA
The stitching between the ground and the power are a little faster as you don’t have to tie of the thread at each point as you do with the data thread. To stitch 7 neopixels and the Gemma can take anywhere between 30 -45 minutes. Longer if you are new to sewing.
Check that all threads are clear of each other. Touching / crossing threads will cause electrical shorts and your project won’t work.
Step 3 Code and Go
Upload the Headdress code to your Gemma. Remember the button press and release to be able to upload the code to the Gemma
This project is similar to the LightUp PointeShoes but that uses a Flora because of the input required from the velostat pressure switch. If you wanted the lights to not react to dancer movements then you could use the above project. Stitching on pointshoes is pretty tricky.