Monthly Archives: May 2014

Pool Pump Controller – in Action!

Summer is finally here, and the hard work on the pool pump controller is starting to pay off. It looks like most of the bugs I ran into last year have been ironed out and it is working like a charm. Except when it doesn’t – but it quickly recovers.

In the video below, you can see the setup and a demonstration of its operation. Unfortunately, there is one more bug – when exiting high speed mode, the controller resets, but in 30 seconds it recovers and picks up where it left off. I think it is an EMP burst affecting the controller as it is in the same metal box as the relay.

A second gremlin sometimes affects the display on speed change, but the display refresh code eventually cleans that up.

For those needing a refresher, here is the initial writeup, and here is an update providing more info on the build, including code and schematic.


Pool Pump Controller – Update 2

Spring is here and the summer pool season opening is just a few weeks away. Over the past few weeks I have been working hard to make key improvements to the pool pump controller I mentioned here.  For the uninitiated, a few years ago I upgraded the motor on my pool pump from a 1.5HP single speed motor to a dual speed motor. The high speed setting is great for vacuuming the pool and performing the necessary maintenance tasks, but eats an incredible amount of power – 10A @ 230V. When maintenance tasks are complete, I can set the motor to low speed and keep circulating and filtering the water, but consume only a few amps. Perfect until the heater turns on. The water flow is too low at the low speed and the water starts to boil in a heater. No way I am going to blow up a $2000 heater. Last season I built the automatic controller, which set the pump speed according to the difference in water temperature as it enters and leaves the heater. For the most part it worked great, but it had a few faults:

  • Sometimes the controller would reset when the motor started at high speed, shutting everything down until the controller came back up.
  • If the controller did not reset, then the display would crash and show no data
  • The latest code revision was forgetting to read the thermometers

Updated Pool Controller BoardIn order to resolve the reset and display issues, I added a few large capacitors to the power bus, increasing the power source fluctuation tolerance. Now it should be able to survive a one second full power outage without reset. While I was adding capacitors, I also added a bridge rectifier to the board power input. The bridge protects the board from Mr. Fumblefingers accidentally applying reverse polarity to the board. It also would allow me to use an AC power source, if necessary. Links to the schematics are at the bottom of the post.

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