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Tag: hobby boards

Home Monitoring Project – Part 2

by on Mar.04, 2012, under Technology

In order to count the pulses from my water and power meters, I purchased the Dual Counter from Hobby Boards.  For an enclosure, I purchased the temperature/humidity case which fit the board fine.

Per the how-to, the dual counter board expects to be connected to dry switches as input.  Since the water softener already powers the water meter, it would not be possible to connect it directly as input.  Also, I wanted to have LEDs to indicate pulses, for troubleshooting and direct monitoring.  To provide the dry contacts for the counter board, I decided to use optocouples.  I found a 10 pack of Vishay 4N37s on eBay, which seem to meet the need.

The water softener I have is a Water-Right Sanitizer Plus.  Removing the front cover of the control head reveals the connection of the water meter to the PCB using a 3-pin Molex KK connector – exactly the same as a common PC fan connector.  I purchased a fan splitter cable, connecting it between the PCB and meter.  I salvaged a fan connector from an unused fan and made an adapter to an RJ45, to bring the connection back to the counter board.  Empirically, I found that one pulse per second equated to one gallon per minute – or stated another way, each pulse represented 1/60th of a gallon.

The power meter I have is a GE I-210 / CL 200.  The manual indicates each pulse represents Kt (in my case, 1.0) watt-hours of accumulation, which is the same conclusion reached in a post by Jan Bottorff.  I had originally guessed a pulse was 1 kWs, as that was the most convenient and seemed reasonable, so I had to adjust this by multiplying by 3.6.  I taped an optotransistor to the plastic cover in front of the IR LED.  Unfortunately, I would receive a lot of false triggers when the meter was exposed to direct sunlight, so I covered the whole meter with a grey bucket zip-tied in place.  I’m not sure how well the utility may like this – perhaps I should put a sign on it to indicate what’s going on in case they stop by.

Counter Schematic

I may try to post pictures later.

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