Drive 12v LEDs using a 'ShiftBar' controller and the Pi

[RenWal]

Hi!

For my current project I need to control a set of 12v RGB-LEDs with the Raspberry Pi. Therefore I bought a ShiftBar LED controller. But now there is a voltage problem: The ShiftBar controller can be directly powered using a 12v transformer. Anyway, the Raspberry Pi GPIO ports output 3.3v.
My question: How can I use the ShiftBrite without damaging the Pi due to the high voltage?

RenWal

[RenWal]

Any ideas?

[rurwin]

The logic inputs will accept the 3.3V signals that the Pi generates, even if the board power supply is 12V. See the datasheet, excerpted below.

LEDdriverspec.png (28.06 KiB) Viewed 1338 times

The output voltage is rather high at 3.8V, but I think you don't need to use any outputs from the board. If you do, then a simple voltage divider would convert it down.

You will need an external 12V power supply, but those are readily available as Laptop power-supplies. I use this one. Connect the supply to the + and - screw terminals on the board. Connect the GND pin on the board to the Pi, but do not connect the +V pin on the board to the Pi.

[RenWal]

Thanks for your answer! I had not got the time to try this yet, but I will do so in the next days.

RenWal

[RenWal]

Finally, I had the time to try whether that setup works. And it does! Thank you very much for your help!
I am still experiencing software problems as there is no Java-to-ShiftBar API available and I therefore tried to port one written for Arduino. (The problem is, Java has no unsigned variables)