After finishing some projects using the original Alpengluehn LED controller, I came to the conclusion that the design was too complex and needed too much manual work to build. So I decided to design a new version of the controller since the overall performance of the design was quite good.
I set myself a few goals for the new design:
- easy to solder but also suitable for high volume production
- daisy-chainable to a reasonable length (< 100 independent channels)
- externally controlled (no firmware on-board)
- suitable for 350mA and 750mA LEDs
- easy wiring
I came up with a design that is again based on the NXP PCA9685 since Ethersex, Linux and Arduino support that driver. It’s also not very expensive and needs almost no external components. Since it features an I2C slave address with 6-bit user-controlled bits, it’s possible to drive up to 96 (6*16) independent channels on a single I2C bus.
Note that this board is not fully assembled (only 9 of 16 channels)
The actual LED driving is done by 16*PowTech PT4115 step-down converter since it is one of the best step-down converters out there when it comes to the price-performance ratio. Also the external components are kept to a minimum which reduces the overall board size and price.
I selected WAGO connectors for the power supply and the LED wiring since they are suppior to screw terminals and soldering. This also makes the design very flexible since you can reconfigure your setup within a few minutes.
You can drive 4 RGBW or 5 RGB LEDs with one board, leaving one channel unequipped. The equilibrium is reached with 3 daisy-chained boards where all channels can be used to drive either 12 RGBW LEDs or 16 RGB LEDs.
As always, you can find the GERBER and KiCAD files on GitHub