Air Conditioner Controller

Take a dumb air conditioner and make it smart so that you can set it and forget it. Uses Particle Photon.

I have an Akita mix. She is the definition of a winter dog but with summer coming, I’m worried that she will get too hot in my house during the day. I don’t want to leave on the air conditioner all day because that will waste a lot of energy but I need to leave it on because she’ll get over heated. I don’t have central air in my house so my thermostat only controls my heat. I wanted a way to cool my house to a set temperature without having to buy a whole new air conditioner so I made a device to do it. I used a power switch along with the very capable Particle Photon to build the Air Conditioner Controller.

In normal air conditioning systems, there’s either an on or and off. In order to avoid the system from just switching constantly, it overshoots (keeps the air conditioner on past the actual temperature). I decided I wanted to do the same thing for my system. If the temperature gets above my target temperature, I want the air conditioner to turn on and continue to stay on for 5 minutes.

The graph below shows the goal of this device. When there isn’t any air conditioning (AC), the temperature will stay at about what the outside temperature is (shown in red). When the AC is on all day, the temperature will plummet down and keep the house very cold which is a waste of electricity (shown in purple). When the AC is only on long enough to overshoot five minutes (shown in aqua), the temperature read inside will start resembling a sine wave (shown in dark blue) with the peak of the sine wave at our threshold temperature.”