Hi I’m looking for a product like the unicorn hat HD but that’s compatible with Arduino - any suggestions?
Im not aware of any pre constructed board, however you may be able to find a tutorial on driving a seperate matrix from an arduino. Arduino also supports SPI which is what the unicorn hat uses so you could likely get the two talking to each other but I dont have any experience in that area so you would be on your own.
Have a look see here, https://www.adafruit.com/category/17 You might get lucky, probably won’t be HD though. https://www.adafruit.com/category/825
If you’re using an Arduino that’s comfortable storing (31616) (a.k.a 768) bytes of data (IE: something with >=2kb RAM), it should be pretty easy to drive Unicorn HAT HD directly from it.
Here’s the pinout for the board: https://pinout.xyz/pinout/unicorn_hat_hd
And the format is basically 0x72, R, G, B, R, G, B, R, G, B …
The 0x72 is the Start Of Frame byte, and is used internally by Unicorn HAT HD to lock on to the incoming data stream and know where each frame begins.
You can use SPI (https://www.arduino.cc/en/Reference/SPI) to shift out the data, or just bit-bang it out on any spare IO pins.
You should delay by about 10ms between each update.