I built my own sensors using the Arduino standard. I built a humidity/temperature sensor that sends data to a free IoT web app called Blynk. I can use Blynk to keep track of the humidity and temps in my tent. For the lights, I decided to go with Sonoff power outlets. They have an iPhone app that lets you set schedules and turn your lights on and off. The outlets also work with the Alexa smart home functionality, so I use them all over my house for other stuff too.
My version 2 of “automation” for the grow room will be to put up my own IOT server in my house and build my own app so I can combine the data from the Arduino sensors I made with the data from the Sonoff and use them to inform the other… i.e. if humidity gets too high, power on the humidifier.
A lot of this is difficult to do via just power management due to the prevalence of digital power switches that don’t cycle when the power to the unit cycles. People who have solved the “turning on and off heaters and air conditioners” via power management have had to look for older model units that have analog power switches.
There are systems out there that can do this, but IMHO they are priced out of range for the average home grower.