Arduinos are small, cheap microcontrollers that can easily read from sensors and control various actuators. @NickWebb has a great intro Arduino: Sensors for Fun and Non Profit class coming up Wednesday night which has open seats. Sign up for his class and do some google searches and what you want to control.
https://calendar.dallasmakerspace.org/events/view/8083
I have Arduino classses on the calendar as well.