So @hebehilhorst went to a concert but I got a bracelet for getting her the seats - better end of the deal anyway let's take it apart
This thing has some expensive work even just the plastic - the clasp is two separate pieces with an actual metal spring in between - can't imagine that was machine assembled.
Watching her try to 3d-print clasps for friendship bracelets I can appreciate the difference
The main body has a more transparent part for the IR receiver, and thicker sections to diffuse the light
On we go to the insides with the iFixit kit
Insides are pretty simple - lots of power for two LEDs, the batteries are 1632 li-ion, likely rechargeable so we can save those from the landfill
Simple IR receiver, filed off IC, and likely some memory and the driver. Single sided PCB.
From probing the thing the copper test points seem mainly for the LEDs
Cool solder blob method of connecting to the batteries, might steal that for something
Overall it's a cool piece of kit - looks like they might still be using MC81F4104 with an EEPROM as @yeokm1 suspected in his teardown a while ago
yeokhengmeng.com/2019/08/teardown-of-ndp2019-led-wristband/
Thought I'd reverse engineer the protocol but then I remembered the internet: github.com/danielweidman/pixmob-ir-reverse-engineering
Finally the friendship bracelets - here's all the 3d printing experiments (how to connect them? What's a good base material?) brought on by a morning of realising she needed them
Hrishi
@hrishioa
In SF in March - Building artificially intelligent bridges at Southbridge, prev-CTO Greywing (YC W21). Chop wood carry water.