Thanks for the replies all! It helps to know about some hardware I didn't even know existed.
In school people do learning projects such as the typical stoplights, etc.
I like to do home projects that are fun, educational, and it helps if they are somewhat useful too. Recently I connected a Fuji temperature control with ramp and soak. I've used it with a SSR to control the temperature of my Brinkman electric smoker. I can smoke a pork butt for pulled pork BBQ and not have the temperature shoot up if the water pan runs dry. Now I'm just using a thermocouple to keep the smoker temperature at 225 deg. F. In the future I'd like to use a probe and use ramp and soak to get the meat from cold to the cooking temperature (190F for pulled pork) in about 10-12 hrs and soak a little, then ramp down to maybe 140F keeping warm. The electric smoker does a good job with addition of some wood chunks for flavor.
The only problem with the Fuji temperature controls for smoking is that the ramp and soak doesn't wait on the meat to reach the setpoint (AFAIK), it just advances the setpoint over time, if the setpoint isn't reached, it doesn't wait. So, if I would use a PLC with with a thermocouple or RTD card, I could monitor the smoker temperature to keep it 225F and wait on the meat to reach done temperature, then turn on a "Done" indicator and allow the smoker to go to 140F (the safe keep warm temperature). Good BBQ from playing with controls!
I also use these Fuji controls (I got a lot of 11 on eBay) for temperature control on my electric radiator room heaters. They are great for keeping cold areas of the house comfortable, I don't have to overheat one room just to keep the bedrooms comfortable.
My other controls use in my home shop is I use EMC running in a Linux PC to control a CNC lathe. I get 3 phase conversion and spindle speed control from a VFD. I also have a CNC mill running off of an old control that I plan to upgrade to EMC in the future. With additional I/O I could automate part feeding, coolant and stuff like that.