Enjoy The Last Throes of Summer With a Nice Pool Automation Project

[Ken Rumer] bought a new house. It came with a troublingly complex pool system. It had solar heating. It had gas heating. Electricity was involved somehow. It had timers and gadgets. Sand could be fed into one end and clean water came out the other. There was even a spa thrown into the mix.

Needless to say, within the first few months of owning their very own chemical plant they ran into some near meltdowns. They managed to heat the pool with 250 dollars of gas in a day. They managed to drain the spa entirely into the pool, but thankfully never managed the reverse. [Ken] knew something had to change. It didn’t hurt that it seemed like a fun challenge.

The first step was to tear out as much of the old control system as could be spared. An old synchronous motor timer’s chlorine rusted guts were ripped out. The solar controler was next to be sent to its final resting place. The manual valves were all replaced with fancy new ones.

Rather than risk his fallible human state draining the pool into the downstairs toilet, he’d add a robot’s cold logical gatekeeping in order to protect house and home. It was a simple matter of involving the usual suspects. Raspberry Pi and Arduino Man collaborated on the controls. Import relay boards danced to their commands. A small suite of sensors lent their aid.

Now as the soon-to-be autumn sun sets, the pool begins to cool and the spa begins to heat automatically. The children are put to bed, tired from a fun day at the pool, and [Ken] gets to lounge in his spa; watching the distant twinkling of lights on his backyard industrial complex.

Spaduino heats up a used hot-tub

[Ryan] and the roomies decided that a hot tub was just what they needed to spice up the place. They hit Craig’s List and found one for the right price. After acquisition and setup they were pleased to find that the jets and pump worked great. But you’re not going to want to stick as much as your big toe into this ice-cold cryogenics experiment. Some poking around in the control system exposed the dead relays which are responsible for switching the heater. Instead of swapping the parts, [Ryan] began building a control system that will replace the twenty-year-old original.

The heating element still works, but it’s rated at 5.5 kW and here’s no way to automatically switch it on and off. [Ryan] found a 60 Amp solid state relay which can handle the load, and plays nicely with his Arduino. Initial tests got the tub up and running again. Obviously you want the tub to maintain temperature and so a thermistor was added to take readings from the heater core. There’s also a potentiometer to adjust the temperature, and an LCD screen to show the current settings. But [Ryan] hopes to add more features over time, like incorporating jet control, and adding wireless communications via an Xbee module.