The CMD is a board with a matrix of APA102 or any other SPI controllable RGB-LED. The board itself can be driven with a voltage from 3V3-5V and controlled over the APA102 driver library. An advanced option is to use the CMD driver library that is also used in the demo firmware in this repository.
| Experience | Level |
|---|---|
| Soldering | |
| Mechanical |
| Type | File | Description |
|---|---|---|
| Schematic | pdf / cadlab | Schematic files |
| Board | pdf / cadlab | Board file |
| Drill | Drill file | |
| BoM | xlsx / html | Bill of Material as Excel/interactive HTML |
| PCB | zip / tar | KiCAD/Gerber/BoM/Drill files |
| Mechanical | zip / tar | FreeCAD/Housing and PCB (STEP/STL) files |
| Firmware (demo) | zip / tar | Test application(s) for using CMD with an ATmega16a |
The pcb is created with KiCAD, the housing with FreeCAD. All files are built with github actions so that they are ready for a production environment.
The circuit board is populated on both sides (Top, Bottom). The best way for soldering the SMD components is within a vapor phase soldering system and for the THT components with a standard soldering system.
The housing has a tolerance of 0.2mm on each side of the case. So the pcb should fit perfectly in the housing. The tolerance can be modified with FreeCAD in the Parameter Spreadsheet.
To test the functionallity of the display, just download the demo firmware above and thorw one of the provied firmwares ( cmd/frame/text) onto an ATmega16a, with connected spi bus and source. The source code of the firmware is located within this repository.
+----------------+ +-------------------------+ +-------------------------+
| A | | # # # # # | | # # # # # |
| T +--+--+ | | | |
| M | VCC +--+ | # # # # # | | # # # # # |
| E +--+--+ \ +--+--+ +--+--+ +--+--+ +--+--+
| G | +------+ VCC | # # # # # | VCC +------+ VCC | # # # # # | VCC |
| A | | X | | X +------+ X | | X |
| 1 +--+--+ +-----+ SI | # # # # # | SI +------+ SI | # # # # # | SI | . . .
| 6 PB7 | SCK +----/------+ SCK | | SCK +------+ SCK | | SCK |
| A PB6 | MISO| / | SS | # # # # # | SS +------+ SS | # # # # # | SS |
| PB5 | MOSI+--+ +--+ GND | | GND +------+ GND | | GND |
| PB4 | SS | / +--+--+ # # # # # +--+--+ +--+--+ # # # # # +--+--+
| +--+--+ / | | | |
| | / | # # # # # | | # # # # # |
| | / +-------------------------+ +-------------------------+
| +--+--+ /
| | GND +--+
| +--+--+
| |
+----------------+
| Type | Link | Description |
|---|---|---|
| APA102 | RGB Full Color LED | |
| T3A33BRG | Harvatek Surface Mount PLCC IC+RGB LEDs Data Sheet |
R. GAECHTER