After installing a Sense energy monitor a few years ago, Keilin Bickar decided to do the same for his water usage. This, however, required a bit more creativity, as you can’t just clamp something onto the water line and have it read electricity. Normally his water meter is read wirelessly via a vehicle passing by on the street. While that would seem to have been an elegant way to accomplish usage tracking, the protocol is closed, and it’s more of a two-way communication rather than something that can be passively read.
Fortunately, the meters also feature a visual display, meaning that in theory it can be read by a camera/computer vision, which Bikar chose to use here. To line everything up, he 3D-printed a mounting plate, which holds a VC0706 Open Smart Camera in position on top of the meter, as well strips of LEDs for illumination. These strips are especially important, as the water usage isn’t displayed on the LCD unless it sees light — presumably to save power as manual reading would be a rather rare event.
Once properly illuminated, the camera takes an image of the LCD and sends it in a 160×120 resolution to to a Wemos D1 Mini Lite for processing. The numbers are then worked out, and sent to Home Assistant using MQTT. Code for the build is available on GitHub if you want to try something similar, though one can only wonder what the utility person will think when something like this is found in years to come!
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Author: Jeremy S. Cook