I had an idea the other day to create a custom thermostat using an Arduino with temperature/humidity sensors. The whole point of the project would be to control the Heating/Cooling system and collect information about temperature/humidity levels. My initial thought is to send all the data to a computer via a serial connection.
I have very limited experience with designing electronic components but I am fairly skilled with writing code. I found some diagrams online for how a thermostat works and I need some help to confirm that this is in fact how my heating/cooling system works.
According to the document I found the 5 wires hooked up to my current thermostat do this:
* RH - This wire comes from the 24VAC transformer on the heating system.
* RC - This wire comes from the 24VAC transformer on the air-conditioning system.
* W - This wire comes from the relay that turns on the heating system.
* Y - This wire comes from the relay that turns on the cooling system.
* G - This wire comes from the relay that turns on the fan.
The problem is I don't know which one does what. They are all unlabeled and red! What testing equipment will I need? I have a voltmeter. How exactly can I determine which wire is which?
My second problem is once I've identified all the wires, how do I activate the heating/cooling system? According to the document online all I have to do is complete the circuit from the 24VAC wire of either the heating or cooling (labeled RH, RC above) with the corresponding wires (labeled W, Y) and also the fan fire (G). Does this make sense? Currently my plan to complete the circuit with the Arduino would be to hook up one of the digital pins to a relay (for a total of 3 relays). Is this the best way to do it? Or should I use a different method for completing the circuit?
My main goal is to learn more about electronics and heating/cooling systems. I thought that this project would be perfect to get my feet wet (or very cold when the furnace burns out because I screwed up.. hehe).
I have very limited experience with designing electronic components but I am fairly skilled with writing code. I found some diagrams online for how a thermostat works and I need some help to confirm that this is in fact how my heating/cooling system works.
According to the document I found the 5 wires hooked up to my current thermostat do this:
* RH - This wire comes from the 24VAC transformer on the heating system.
* RC - This wire comes from the 24VAC transformer on the air-conditioning system.
* W - This wire comes from the relay that turns on the heating system.
* Y - This wire comes from the relay that turns on the cooling system.
* G - This wire comes from the relay that turns on the fan.
The problem is I don't know which one does what. They are all unlabeled and red! What testing equipment will I need? I have a voltmeter. How exactly can I determine which wire is which?
My second problem is once I've identified all the wires, how do I activate the heating/cooling system? According to the document online all I have to do is complete the circuit from the 24VAC wire of either the heating or cooling (labeled RH, RC above) with the corresponding wires (labeled W, Y) and also the fan fire (G). Does this make sense? Currently my plan to complete the circuit with the Arduino would be to hook up one of the digital pins to a relay (for a total of 3 relays). Is this the best way to do it? Or should I use a different method for completing the circuit?
My main goal is to learn more about electronics and heating/cooling systems. I thought that this project would be perfect to get my feet wet (or very cold when the furnace burns out because I screwed up.. hehe).