These backpacks has a few places where stickers can be attached with velcro. The kids got some stickers with the bags, but these are just static ones.
Here came the idea. What if I create something personalized for them. Something with their own name, what even has some light in it.
So I needed a 3D Printed cage, with some electronics inside. To keep it simple I chosen an Attiny85 and APA102 LEDs.
I wanted something can be charged. To keep it as slim as possible, the normal AA or AAA size rechargeables was not really a good option (first I was thinking about, but finally I thrown the idea). So I chosen a Nokia BL-4C battery. There are two problems with it. You need a proper Li-Ion charger and as the LEDs need 5V, you need a boost converter to power it.
In addition I wanted to cut of the power after certain amount of time - Kids never switch of the toys.
So one push button for switch on, one for switch off if you want, and timed switch of by the MCU.
Here is the circuit:
I built this on a circular board:
(This is the first prototype, not the actual working one)
Then I designed a case for it.
Actually I was able to print the 3D parts and assembled the whole thing, but I wasn't really happy with the result as I had continuous problems with the 3D printer (the Geeetech, as the Robo3D was completely dead)
Finally the signs appeared on the bags, and the kids were happy with it:
The project was closed...
...but, as you can expect kids, are kids, and they have schoolmates. So "orders" arrived - who else needs it. :-)
All of the design files are available on my github:
It has been cleaned up, so just the actual design is in there.