Hey all,
I hope I'm using the correct terminology in the title...
I'm working on a project for remotely controlling my home AC by intercepting the IR signals from the remote control, parsing it to understand the current settings, and retransmitting a signal to the AC so the setting will be applied.
My current issue is that the power button of the remote is only to toggle the AC power and so I don't know, at a given point in time, if the AC is surely on or not.
I was thinking of checking the LEDs of the control board to figure that out. It has two LEDs, one red for off and another green for on. The LEDs are connected to a 5v rail and are sink-driven by the existing controller. I want to read the level of this line taking in consideration that my MCU is 3.3v while the existing controller is 5v. My initial thought was to use a voltage divider to bring the 5v (when the LED is off) to 3.3v and read that from a GPIO but that would essentially mean I'm pulling down the line, no?
Would just using high resistor values be good enough here or is there a better solution to get the logic level?
Thanks in advance!