Flash/Splash: A Pool Controller PCB

Years ago, I showed off my hacked-in Raspberry Pi pool controller. It's been marching along for four years — protoboards, jumper wires, electrical tape, the whole “don't touch it, it's working” experience. It was solid enough, and it's been fun to heat the spa from my phone on the way back home from a club, or tweak the pool pump schedule just right, but it was always my intention to do it up proper.

So I finally made the time and spun up a proper board. FlashSplash v0.2 is a custom PCB that kills the spaghetti wiring and puts everything on one clean, stable, replaceable board. For about $30 in parts and $50 in fab costs, I’ve now got a pool controller that doesn’t look like a student project. It handles all the power conversion, relays, and logic right on the board, so the Pi can do what it does best: run the show.

FlashSplash v0.1 uses the Raspberry Pi Zero W and was designed from the ground up in EasyEDA. It takes a raw 24V AC from common pool transformers and converts it into stable DC rails and provides relay control, sensor headers, and GPIO breakouts. The board makes it easy to automate pumps, heaters, lights, and valves while integrating DS18B20 and DHT sensors for temperature and environment monitoring. The goal is to provide an open-source, reliable, and customizable pool/spa automation solution that hobbyists and makers can replicate, extend, and improve.

Features

• Smart control of pool pumps, heaters, lights, and valves using a Raspberry Pi. It supports both automation scripts and manual control via web or mobile UI. Typical use cases include:
• Scheduled on/off control for pumps and lighting
• Relay control for 24V AC actuators (e.g., Intermatic pool valve actuators)
• Integration with sensors like DS18B20 for temperature monitoring
• Local-only or remote-access (via port forwarding or VPN)
• Safe power management with voltage conversion and protection

Control Panel

The new control panel is where the project really shows off. It’s a Raspberry Pi 4 paired with the official 7" touchscreen, running a slick interface that actually feels fun to use instead of some clunky beige box UI. The panel shows animated bubbles when the booster pump kicks on, steam rolling out when the heater fires up, and arrows that shift to show water circulation direction. You can set spa temps, toggle lights, and schedule pumps without leaving the couch — or hit it remotely from your phone. It’s basically turning the pool into a toy you actually want to play with.

I'll be making the source code for both the server and control panel public on github shortly. Feel free to reach out if you want early access or have any questions or want me to build you something custom...

 

Let's Build

I dropped everything — schematics, Gerbers, instructions, the whole deal — on OSHWLab:

FlashSplash v0.2 - OSHWLab