Power / current monitoring in order to deduce energy consumption is of big interest. Does anybody already designed such a prototype for twine motes ? Thanks
This should work as long as you are not using an external sensor for anything else, and your wi-fi router is backed up with a UPS or other independent power supply:
Assume your twine has fresh batteries and is running on USB power which comes from an AC adapter. Connect a simple light sensor to either the breakout board or the moisture sensor, and plug a small light bulb into the same AC outlet as the USB adapter, shining on the light sensor. When the AC fails, the twine will switch to battery power and the light will go off, causing the light sensor to read open (high resistance). This will show either "open" or "dry" to the rule you code, depending on which device you used.
I asked about a rule for "If Twine has not report in x minutes..." for the purpose of knowing if power or internet is out at my vacation hut. they said they would put that on the list. Should be easy, since the rules are server-side.
Answers
Assume your twine has fresh batteries and is running on USB power which comes from an AC adapter. Connect a simple light sensor to either the breakout board or the moisture sensor, and plug a small light bulb into the same AC outlet as the USB adapter, shining on the light sensor. When the AC fails, the twine will switch to battery power and the light will go off, causing the light sensor to read open (high resistance). This will show either "open" or "dry" to the rule you code, depending on which device you used.