💬 Battery Powered Sensors

  • Yes but in this case the last massage will be the same like the previous, only the battery level will be below some predefined value. i don't like this. I will think how to solve this.

  • @tiana - Of course you can do this in your code.

    Just read the battery level and when it gets to the lowest level you decide upon (maybe a little testing needed here) then include the line...

    if(battery_level_read < battery_low_level){
    send.msg(your last message)
    sleep(long time period)

    You need to define all the things above as normal for variables (floats for the battery reading and levels and UL for the long sleep)....

  • @tiana I agree with @mfalkvidd , normally it is the Controller which sends out the warning to change battery, certainly Domoticz has this provision incorporated?
    Here the batteries are read at approximate 12 hour intervals, and Domoticz is preset to signal a warning below 1.7v, which is days or even weeks from actually dying. If I'm away or forgetful it will cease updating anyway and flag Red on the display.
    Once you have established the consumption curve for your batteries until flat, easy enough to set the warning threshhold before the Node dies...

  • @tiana
    Create dummy contact sensor on your node and if node sends last message, it will trigger this contact before "die".
    So controller knows, that it was last message and node is off.
    But better is allow controller do its job, like wrote all others.
    I personally check battery level and "no incoming messages in supposed interval" to send alert to my e-mail ( and SMS ).
    In this example tank level sensors sends every 10min, so after 3 messages lost, I will be informed.


  • Thanks for the ideas, i will modify the code to use LowPower lib and will cut the power to the radio module to increase battery live, when last massage is send the node will never power the radio module, will be only short interrupt and go again to sleep forever. This will give me power usage 20times more than self battery discharge. Which have to give me node uptime around 260days with coin cell battery.

  • @tiana
    And for what will be that offline node usefull?

  • Door/Window/Button

  • @tiana
    Forever sleeping door sensor with low battery?

    "when last massage is send the node will never power the radio module"

    Why door sensor, if it never sends message?

  • @kimot
    At all of the time 328p will be in sleep forever, when button is pressed interrupt is triggered and wake the 328p power ON the radio send info power OFF radio and go sleep forever.
    Only when battery level go below critical level. the radio stay OFF and only interrupt and sleep forever.

    I am almost ready with the drawings of the hardware, and next week start work on software... you can see the project in the openhardware.io i gonna upload it later tomorrow.


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