Make: micro:bit neopixel sleeve

After failing to get the cycling jacket done I was desperate to create SOMETHING wearable with neopixels and the micro:bit. I love my micro:bit belt but it drains a lot of power, even from separate batteries. I wanted something smaller that would run off the micro:bit, more subtle, but just as fun.

Going back to teaching in September I’ve had to dust off my suits and that’s when I thought of putting neopixels in the sleeve of a work jacket 🙂

Materials

1. 4 sewable neopixels (the cheapest I’ve found in the UK are to buy 20 from CPC, still quite pricey)
2. Conductive thread
3. Velcro (any decent craft/wool shop will have velcro strips)
4. A jacket with long sleeves
5. micro:bit
6. micro:bit battery pack with batteries
7. Ring terminals
8. M3 bolt and nuts
9. Multi thread wire – 3 strips as long as your wrist to your chest

Instructions

1. Measure the inside of your sleeve
2. Cut your 2 pieces of velcro – the rough bit and the smooth bit – the smooth bit is going on the inside of your sleeve so your wrist won’t be shredded when not wearing the neopixels
3. UPDATES below have an alternative to sewing directly into velcro. Using the conductive thread, sew the 4 neopixels onto the smooth side of the rough velcro strip. The rough side is going to stick to the jacket. 
4. Sew the 3 wires onto the rings of 3 ring terminals 
5. If the terminals look like they could touch, insulate them with cellotape. It’s really important none of the 3 connections touch. Make sure the threads don’t touch or the metal parts of the ring terminals
6. Strip and place wire into 3 ring terminals. Crimp like the hulk
7. Take the + wire and connect to the 3V of the micro:bit
8. Take the – wire and connect to the GND of the micro:bit
9. Take the -> wire and connect to Pin 2 of the micro:bit
   1. To connect to the micro:bit I used more ring terminals, crimping and M3 bolts and nuts in the micro:bit holes. The only problem with this way of connecting wires to the micro:bit is you might get some problems with the other pins between 0, 1 and 2 that control the LED lights of the micro:bit. I’m not using the lights in this project so this isn’t an issue for me. 
10. Sew a smooth piece of material onto the inner of your sleeve.
11. Stick the neopixel velcro onto the sleeve
12. Run the wires up your arm and place the micro:bit in the inside pocket alongside the battery
13. I used the belt code to create a rainbow effect

UPDATES

With the finished project I realised the conductive thread was exposes on the sticky side of the velcro. So everytime I pulled it off the jacket, it risked pulling out my thread or worse  – crossing wires and shorting the micro:bit

So instead of step 3 above try:

Sewing the neopixels into a piece of material first. I used a piece of cross stitch material. Then machine sew that piece of material onto the velcro. It’s a tight fit but now my conductive thread is safe and much neater:

I also sewed the terminal rings on at different lengths to guarantee they wouldn’t touch each other. You can see how much neater the stitching is on the material: