Large character display which can be configured anywhere between 1 and 64 characters and each character is 120cm x 120cm (about 5" in old money) squared, there are a lot of displays on ebay but they are quite difficult to control and dont work well on 24V industrial supplies, I just needed some which could be mounted in various cases for different purposes for simple remote displays (number plates, job numbers, scoreboards, counters etc) which the only programming would be to send a five byte serial message (0x02 + 0x03 + address (0-63) + ASCII-CHAR + 0x04 )

You can also change the brightness of the character (1=dim, 10=bright) by sending an ASCII value of dec 130 to 140. (outside the normal ASCII char set) the font is supplied in the header file and can be modified to add custom chars etc

The connectivity is plain TTL 3V3 serial input (it doesnt transmit anything back only received) so I could connect it to USB, Modbus, bluetooth or ethernet serial adaptors or some of my other industrial boards I have made in the past.

Each character costs about $10 to make using LCSC and JLCPCB

As you can see it uses a $1 8x8 led and puts 4 of them on a board to large it up, each pixel is 4 leds so we get a bigger 8x8 display than we would otherwise get (I really diddnt want to solder 64 LEDs on though I did consider just using a 5x7 font which would only be 35 LEDs) Not much to say about the design, the 9-24V and serial feeds all the boards in the chain and you set an address on each board (using solderable resistors)

MPLABX XC8 Project attached which works with the PIC16F1872 (should be easy to modify to any other 8 bit pic) attached to this project so hopefully you can access it :-)