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Thread: HVAC thermostat SmartStat Micro (using Teensy) at JavaOne 2013 Sep

  1. #1
    Senior Member
    Join Date
    Nov 2012
    Salt Lake City, UT, USA

    Red face HVAC thermostat SmartStat Micro (using Teensy) at JavaOne 2013 Sep

    They must be hard up for presentations, since ours was accepted: a small, inexpensive, open-source firmware programmable thermostat using in part a Teensy module: SmartStat Micro.

    It uses the TMP102 and HIH613X sensors (either/or, the HIH613X gives humidity and temp), a small 16x2 OLED display using the WS0010 chip which also has a 100x16 graphic mode, and the Wiznet 812MJ module. At the moment we are using Teensy++2 since that all stacks together nicely with the PJRC adapter board, but are planning to move to Teensy3. The TMP102 are about $2 singles and once configured can act as a self-contained thermostat with a call for heat (or cooling) output and programmable hysterisis (also called deadband, but that doesn't sound as nice).

    One of the first in-place tests will be driving the 1 HP 240 VAC evaporative cooler here at the office. In this case I need to switch two legs of 120V at 10A which together comprises the 240 single-phase. It's an old beast: newer models have the same cooling capacity at 120V and less current.

    We might offer a kit or partial kit of parts (the SSRs are rather pricey but there are many surplus modules available at reasonable price).

    We will also be logging data to a cloud service and/or Google App Engine which could aggregate data from numerous SmartStats. I'm interested in doing this to get a log of outside temp/humidity and inside temp/humidity to monitor cooling efficiency as well as cooling load.

    After JavaOne I plan to continue down this path and make this part of home and office radiant heat control and monitoring.

    As soon as we have a public project site up I will update here. It's planned for all the software and firmware to be open-source as well as schematics and general project documentation (BOM, theory, etc).

    Best regards
    Bruce Boyes
    Last edited by bboyes; 07-29-2013 at 08:56 PM. Reason: correct spelling

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