Having issues with a setup similar to the post below.
Here is a (crude) wiring diagram for my setup. I’m not sure where the problem lies, but it’s likely my wiring.
Read the 0-5VDC output from the 24VAC controller and convert that to a PWM signal for the servo. The whole thing should be powered from a single wall powered connection (120VAC). Note that the 24VAC controller and the servo are a must. Everything else is optional (including the Arduino). There is no 5VDC reference out from the 24VAC controller. It only provides 15VDC, and not enough current to run the Arduino and servo.
The problem is, once the Arduino is attached, the output from the 24VAC controller becomes 4.7V to 5V, as confirmed with a voltmeter, instead of 0V to 5V. This is a really odd problem, and leads me to believe it’s wiring related.
My concern is that since the 24VAC controller output is not powered through the same ground as the Arduino, there is some wiring issue causing this voltage jump.
The other potential issue is that everything is wired as it should be, and something is wacky with my 24VAC controller when attached to the Arduino.
If the former, please educate me as I am out of ideas outside of an opto-coupler which I am trying to avoid. If the latter, please let me know I have the wiring correct and it’s likely a problem unrelated to my Arduino or wiring and I need to fix my 24VAC controller.