This is a project to create a pair of programmable neko mimis that feature ten LEDs.
Please be aware that the LEDs can easily exceed the max power draw of this circuit design. It is highly recommended not to exceed 150 mA. They're cat ears, you don't need to blind everyone - keep the NeoPixel library brightness down to around 50 or so, tops :)
Also be aware some people are photo sensitive - these are meant for rave environments. For environments where people may not expect flashing lights (and where they do...) please be considerate.
- ATSAMD21 microcontroller (ARM Cortext M0)
- Ten WS2812b RGB LEDs
- Power and status LEDs
- One capacitive touch zone - though this isn't used in the example code
- Native USB (you can even use it as a keyboard, hopefully)
- Designed to be put in cat ear headbands. Meow!
- Probably a fair number of bugs and bad design decisions!
I licence this work under CC BY-SA 4.0
Also, I'm obviously not responsible for injuries or anything like that - this is definitely not a safety-tested, commercial project. Build at your own risk. It probably won't even work :)
You really shouldn't draw over 50 mA or so of power, you're probably blinding people if you do :) - see warnings above. Thus, you should be fine to input all the way up to the linear regulator max voltage rating of 6V - but you're wasting energy over 3.3V. Thus, 3x NiMH batteries or a 3.7V Lion battery would be good power choices - be smart and sensible though. Batteries can be dangerous. There is no hardware over-discharge protection, so use only batteries with this protection!
Boards can be ordered from Osh Park - that's not an affiliate link or anything, just a convenient source. And they're purple.
I have forked and modified the Adafruit Trinket M0 file from the Microsoft USB Mass Storage Bootloader for the ATSAMD21. The Trinket M0 bootloader also works, tho!
| Component | Manufacturer | Qty |
|---|---|---|
| This board | Whoever you choose | 1 |
| ATSAMD21E18A-AU-ND | Microchip Technology | 1 |
| S2B-PH-SM4-TB(LF)(SN) | JST | 1 |
| 0.1uF 0603 Capacitor | Any | 10 |
| 1uF 0603 Capacitor | Any | 2 |
| 10uF 0603 Capacitor | Any | 2 |
| WS2812b LED | Worldsemi | 10 |
| UV/blacklight LED 0805 (or fave :) ) | Generic | 2 |
| AP2112K-3.3TRG1 | Diodes Incorporated | 1 |
| BAT54-TP | Micro Commercial Co | 2 |
| USB3076-30-A | GCT | 1 |
| 510 Ohm 0805 Resistor (diff if UV sub) | Any | 2 |
| 330 Ohm 0805 Resistor | Any | 1 |
| 3.5 x 6 mm push button switch | Generic | 1 |
The example C++/Arduino code is designed to pretend the board is an Adafruit Trinket M0, and is for use with the Trinket M0 bootloader.
Thank you to the following people:
-
Ladyada and Adafruit - for building excellent products and teaching people electronics. I used a lot of Trinket M0's in prototyping this. Seriously, people, go buy their products - they're fantastic (and the boards are way cuter than some others, especially look at the Metro M4 Express - it's just adorable).
-
OpenMoji - this is the source of the emoji used on the board silk.
-
Q - for being an awesome friend who has helped with so much of the EDA side of working this all out. Thank you for answering late night messages with silly questions!
-
JoJo Siwa - because the inspirational quote comes from one of your songs, and your concert on the D.R.E.A.M. tour I went to in Cardiff was amazing. I'm not sure if it's your original quote tho, so I didn't quote it as you - I think I've heard it before? Either way, very inspiring performance! Keep things fun and positive and spread the positive energy, people!
This was essentially a light strip on a cat ear shaped PCB.
This added an ATSAMD21 microcontroller.
This is the release version - it fixes the major bugs and makes them ready for general use.
Minor update - reset on back where it's useful, more room to insert battery... not much else :)