My father and I created an automated pool controller to control the times our pool pump comes on automatically with a raspberry pi. Which enables it to be controlled from any device. Our pool timer had broken twice in three months costing us $120.00 for the two replacements. By replacing the timer with a raspberry pi microcontroller, any of us could control it without having to go out and open up the service box repeatedly at the times it needed to be ran. The raspberry pi also was a more cost effective replacement considering the pi was $45.00, the solid state relays were $18.00, and the other equipment needed was about another $25.00. The automated pool control gave us far more capabilities for less than we had paid to replace the timer twice.

My father developed the program that runs on the raspberry pi to control the pool pump, waterfall, pool lights, and give live readings of pool temperature, solar temperature, and outside air temperature. I designed the 3d printed the case to hold the raspberry pi and a set of solid state relays inside the service box along with three mounts to hold the temperature sensors. Now we enjoy ease of use controlling the pool from our smartphones.

https://www.hackster.io/mmackes/pool-controller-8dfa69
 

The case for the pi and relays was printed in PLA. ABS would have been better, however may be difficult because of its size.

The temp sensor holders were printed in ABS so they could withstand weathering.