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Designing a Pool/Spa Management System

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    Designing a Pool/Spa Management System

    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"><meta name="ProgId" content="OneNote.File"><meta name="Generator" content="Microsoft OneNote 12"> I posted part of this message as a reply to another thread on use of ZigBee. But I thought I would start my own thread to get as much feedback as possible. I'm very open to any and all feedback.


    I'm creating a custom controller for my Pool/Spa system that will control several aspects and integrate it with HomeSeer. My "Pool/Spa Management System" will consist of a small microcontroller circuit installed outside near my pool equipment which communicates via wireless with a computer interface connected to HomeSeer via USB.

    The Microcontroller communicates with HomeSeer via Xbee modules, which use a modified ZigBee stack. These modules take the 802.15.4 stack (the basis for Zigbee) and wrap it into a simple to use serial command set - so you can easily script it via ASCII commands.

    The Project:

    Phase 1 is simple power management/control, and will control power to four items via a relay module. The items it will control are: (1) pool filter, (2) spa low, (3) spa high, and (4) spa heat. Note: I had originally planned to do this with Z-Wave "contactor" modules, but quickly abandoned that strategy when I realized that I would need four of these @ $127 each!

    Phase 2 will install sensors for the following items: water temp (pool), water temp (spa), Ph level, and Chlorine levels.

    Phase 3 is the most difficult and ambitious, but I know its possible since there is a very high end system that does this and is used my many Hotels and public pools. Phase 3 will use the PH and Chlorinity data to control valves/pumps/solenoids to add pool chemicals to keep the water chemistry at the desired level. Since this system would always be running while the filter is on, theoretically the water chemistry would always be perfect. The most difficult part of this phase will be finding the right pumps, or electronic valves, but the eventual payoff would be awesome.

    Phase 4 (if I get this far) would add a pressure sensor to the system, and when the pressure maintained a high-level over a pre-determined amount of time, it would initiate an auto-backwash sequence via electronically controlled valves. From an automation standpoint, this is possible, its just highly dependent on finding the right valves and piping.

    All of this can be managed with one microcontroller, so the cost of adding on additional sensors or control devices (i.e. valves), to an already existing controller is very low. The only caveat is all devices being "driven" by this controller must have wired connections to it. Therefore, this solution is primarily useful when you have areas where there are a lot of things to automate in one location. (i.e. pool systems, sprinkler systems, garage areas, etc..) You can however, install multiple controllers throughout your house/yard.


    I'm currently in the prototyping part of Phase 1, and I have a microcontroller module communicating via XBee with a computer-connected module where my HS sever is. I'm currently building the relay board, so the microcontroller can toggle the 110/220 volts used by the pool equipment.

    My next major remaining task is to write a HS plugin to talk to the Xbee module via ASCII serial commands and update virtual HS devices. This will be the most difficult part of the project for me since I'm a hardware guy (and microcode) and I've never written a HS plugin. I welcome any and all help in the development of the HS Plug-In needed to communicate with the Xbee module,

    Just to set expectations, I do have a full-time job in a different area of technology, so this project will probably take several months to complete phase 1 & 2, phases 3 & 4 are "dream goals" right now, so I'm not sure when/if those will ever get completed.

    The great thing about this solution is its low cost. The microcontroller modules and the computer interface modules can be built for $50-100 each (the cost varies depending on the microprocessor needed and the XBee module chosen). If a low power Xbee module is sufficient (for normal sized houses), the cost is closer to $50. This would make them about the price of a Z-Wave light switch.

    You also only need one computer interface module per house, and just add microcontroller modules as needed; ex: one for the pool system, one for sprinkler system, one for controlling/monitoring video cameras.


    I truly like your project and believe that although ZigBee has had a slow start, it will pick up speed. I believe this mostly due to two factors:
    - The utility sector has chosen ZigBee, as that is now part of many of the power meeters.
    - I heard (not confirmed) that Control4 has build in power monitoring in their dimmers and switches (might be a wish only)

    In addition I believe that consumers want to save energy and I believe they may even be willing to pay money to save energy. Thus the focus on power meassurement in ZigBee should hopefully drive vendors of dimmers and switches to adopt the standard so we can get competition to Z-wave. Competition is good.

    Please keep us updated on the project - I am super eager to learn more as you progress


      azrobbo & v8dave
      I would suggest reading these posts:

      Both of you seem to work in the same direction.

      Also I would suggest spending a little time looking into the code developed by this guy (I found this on the HS forum too). Although his implementation might not be 100% compatible ZigBee interface, I suspect it might be close