Putting the melexis 90614 in sleep mode

The answer is, you can’t, or at least, I can not. Already ran circles around the garden, dug a hole, but the thing still consumes happily its 2 point whatever milliamperes whatever you do. And it is a 3.3v version. So, back to the drawing board for the cloud detector and put it behind a timer unit that does allow a low current mode. The timer unit turns the modem plus the i2c melexis on every 5 minutes for 3 seconds, and this improves the battery life by a factor 5 approximately.

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This shows the outdoor non-contact thermometer, the timer unit is up north. The battery is the yellow part (a 3.6v cell phone replacement part consisting of three AAA’s), the radio modem #arduino combination from LowPowerLab is the red PCB, and the metal TO-39 pill is the melexis thermopile that sticks through the Hammond box cover.

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By cutting the PCB for the timer unit in this shape you can squeeze it in the existing design which is in a Hammond standard box. All control goes via a n-channel mosfet, which is over dimensioned because you could theoretically switch the microwave oven in your kitchen on and off with this one. But I had it unused on the shelves somewhere.

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Backside of the timer unit, should be a standard thing if you ask me on a experimenters board. I’m in general not happy with timer units, but I saw no other solution for this experiment.

Upper left: outdoor temperatures (blue is NTC above a window, red is NTC furhter away, green is IR temperature) Upper right: light outside Lower left: IR temperature living room, Lower right: air pressure
Upper left: outdoor temperatures (blue is NTC above a window, red is NTC further away, green is IR temperature)
Upper right: light outside
Lower left: IR temperature living room,
Lower right: air pressure

And as we write the weather starts to improve, because, the green line in the upper left plot shows that we are getting clearer skies (a delta temperature greater than 3 degrees indicates this). Occasionally some clouds are passing by.

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