I have been experimenting with controlling 5V LED pixel string (WS2801 ICs) with the SPI output on the Raspberry Pi with great success. I am trying to increase the length of the string (without adding more LEDs), but when I do this I am experiencing voltage drop and brown-outs towards the end.
In my mind I have two solutions:
1) Increase the diameter of the cable between the pixels
2) Use a higher voltage
I don't really want to increase the thickness of the cables I am currently using, and to get any great distance the diameter needs to be quite large!
If I purchase a 12V string of lights, power them separately from the Raspberry Pi (sharing a common ground), can I still use the 3.3V output of the SPI data and clock pins to control them, or would I need to bump this voltage up too? If so, what is the best way to do this while still maintaining high frequency updating?
Also, if anyone has any alternative solutions, would be happy to hear those too!!
Thanks for your help,