[Jeffrafa]

I setup something similar this year for basic open loop shooter and mechanism testing. Ours consisted of a Teensy, a potentiometer hooked to an analog input, and a PWM output using one of the pwm libraries. To help identify center on the pot (for calibration, and for setting neutral output), I set the integrated LED to light when the potentiometer is within 2% of mid-range. We successfully used this to run both jaguars and victor 884's, there's no reason it shouldn't work for 888's as well.

Could you post your code, and maybe a photo showing how you have it connected?

For the victor, you shouldn't need the +5 wire, just signal and ground.

I found the best way to test and troubleshoot my arduino sketch was by driving a hobby servo (a vex servo would work too). Once you get that working correctly then it should work with a victor once you complete the calibration sequence

I don't have my sketch readily available, but I may be able to pull it up tonight for reference.