Monitor the state of a LED on another device

I want to make a window air conditioner wifi capable. I can wire into the existing switches with relays to turn it on/off and set the temperature up and down. Now I want to get feedback from the a/c to see what state the unit is in. I want to do it by monitoring if the Cool LED is on, and if the compressor is running. The compressor pin goes to +.5 volts when it is on, 0 when off. The Cooling LED is 2 volts when on. I am thinking these could be monitored with an analog pin of either my Raspberry Pi or and Arduino MRK1000.

How can I monitor this with Cayenne?

if you can get the reading on your arduino then you can send them to cayenne using:

if (reading < threshold){
Cayenne.virtualWrite(channel, 0, "digital_sensor", "d"); //make two state widget 0 indicating the ac is OFF
Cayenne.virtualWrite(channel, 1, "digital_sensor", "d"); //make two state widget 1 indicating the ac is ON

Thanks Shramik! I will try that.