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I recently made my friend Matthew a suit with hidden LEDs in it. So that his partner, Hannah, wouldn’t be out-blinged, I made her a disco necklace.


Video demo

I used an Adafruit Gemma (124-5508) and a strip of neopixels. These were powered by a LiPo battery. I made a little velvet bag for the battery and flora.


Velvet case, hand-sewn 


Gemma and battery were stuck together and slipped into the velvet case

I used three black wires to power and control the neopixels from the Gemma. I plaited them for a pretty effect. I did the same for the other side, although these were not electrically connected.


Plaiting the wires 


Plaited wires made the “chain”  

To make the chain large enough to fit over the head, yet not be too long when worn, I made a very rough closure system. I just left a gap in the non-electrically connected plait and threaded the electrically connected plait through it. Either side of the “gap” I put heat shrink to stop the plait from un-plaiting.


Closure of the necklace  


The electrically connected plait went through the other plait 

To make the neopixels and soldered connections a little less “electronicy” I used waxed cotton (that I usually use in leatherwork) and did West Country whipping around the joints and neopixels.


West Country Whipping around the neopixels, using waxed cotton


Close up of the west country whipping


Whipping around the neopixels

Verdict: Cool to look at, but still a bit too heavy to wear for long!

Bonus video

 Parts list

Item Supplier Stock number
Adafruit Gemma RS Components (124-5508)
Neopixel ¼ 60 ring Adafruit 1768
Lithium Ion Polymer Battery – 3.7v 2500mAh Pi Supply -
I am an inventor, engineer, writer and presenter. Other stuff: Royal Academy of Engineering Visiting Professor of Engineering: Creativity and Communication at Brunel University London; Fellow of the Institution of Mechanical Engineers and have a PhD in bubbles; Judge on BBC Robot Wars.