I recently inherited an arduino set up from someone else in the lab and trying to debug it but seems to be coming across a strange problem. I'm trying to use an Arduino Pro mini (5V 16MHz) to control 2 piezos. However, if I use a direct output from one of the Arduino Pro mini pins into the piezo controller, the piezo turns on for 2x of the time that I want it to turn on.
Other person in my lab circumvented this problem by wiring the arduino pro mini to an arduino uno (output from pro mini goes into pin 7 on the uno) and then this subsequently controls the piezo controller. The output of the uno board into the piezo controller is from A0 and GND pins. My second question is how the Pro Mini to Uno board to the piezo controller can work? I'm simply trying to output a HIGH and LOW voltage into the piezo controller.