Author Topic: WH2C Transmission timing drift  (Read 517 times)

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Offline pfletch101

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WH2C Transmission timing drift
« on: May 26, 2018, 11:05:06 AM »
I have a couple of WH2Cs, reporting downstairs and upstairs temperature and humidity values to my energy control and monitoring system via a Raspberry Pi with some custom code. The other morning, I noticed that they had both simultaneously stopped reporting at just after 4:30 am. Each of the sensors report their readings almost exactly every 48 seconds, but there is some (very slight) drift. To cut a long story short, it turned out that the transmission timing of the two sensors had drifted in such a way that their transmission times had become close enough to simultaneous that their signals overlapped and could not be separated from each other or decoded). Because the drift is very slow, the problem does not resolve itself within any reasonable time (it had persisted for 6 hours when I noticed it), and you have to restart one of the sensors (by removing and replacing its batteries), at which point everything works again. This, of course, changes the ID of the restarted sensor. I can't think of any long-term fix for this, but am posting mainly as a 'heads up' for others who may find themselves in a similar situation. Suggestions on a postcard....?!
« Last Edit: May 26, 2018, 03:08:33 PM by pfletch101 »
Vantage Pro 2+ connected to Raspberry Pi running weewx by means of Meteo-Pi - data incorporated in domestic energy production (PV) and use monitoring system.