Components: Raspberry Pi 3, DHT22 temp/hum sensor, 16 Channel Relay Board, power supplies, a box, wires and shit. (Optional: power socket plugs, more sensors, different sensors)
First you install the Raspbian operating system on the pi. The software you install for the control is called Mycodo, which an awesome person has on the web for free, open source. Wiring shit is a pain in the ass, but not super hard. Just go over things multiple times, because you are dealing with house current. Go into the raspberryPi and connect to your wireless network.(wifi on board) Then it's just a matter of setting things up in the web interface and plugging things in.
I have my lights on a timer, though 848 watts blew a relay, so I had to split it to two. (I'm guessing a high peak at turn on) My 730nm lights are on a separate timer. AC and heater are using maximum/minimum temps, though you can use PID controls that vary your temps to be cooler over "night" and warmer during the day. It emails me if the temp gets too low or high, or just to remind me the lights came on.
You CAN use a CO2 sensor and have a relay control stuff with that, though I didn't do it because the sensor is expensive. You can also use a sensor that measures soil wetness so it auto waters your plants when they are too dry. (the chirp, because it doesn't corrode like other sensors)
My box looks AWFUL! I mounted it in a wine box that I painted, and the inside looks like spaghetti with all the wires. I have 4 x 15 amp circuits feeding from a subpanel into computer case plugs in the bottom of the box, and ten single sockets in the side for everything to plug into. In the future (when I automate watering) I will add another 10 to the other side. I did have some growing pains where I screwed up settings and my lights screwed up, but when you have someone who can handhold you (me) you won't have to deal with that crap.
https://github.com/kizniche/Mycodo
