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  3. Low Power LED detection : Voltage Divider or RC Time?

Low Power LED detection : Voltage Divider or RC Time?

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  • Puneit ThukralP Offline
    Puneit ThukralP Offline
    Puneit Thukral
    wrote on last edited by
    #1

    Hello
    I have a smart meter in my apartment on which an LED glows when the power supply switches from the grid to a backup ( in case of load shedding etc).
    Today, I use an Nodemcu running ESPhome to detect the LED glowing on or off status by doing a voltage divider on a LDR. This is being powered through a phone charger. I check the status on a digital pin.

    Now, in order to improve the WAF points, I need to make is battery operated (wires are ugly - simple), hence I would like to run it on Arduino Pro mini running MySensors & AA/AAA batteries
    Which is more power efficient - LDR with voltage divider or LDR with a capacitor using the rctime library?
    Year to date LED was on 103 hours

    0dbaf16e-8b71-4e80-a4ba-1275e6156f6f-image.png

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    • skywatchS Offline
      skywatchS Offline
      skywatch
      wrote on last edited by
      #2

      @Puneit-Thukral A photo-transistor maybe better as it will draw less current in 'off' mode. Google phototransistor applications and there will be another learning opportunity for you ;)

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      • skywatchS skywatch

        @Puneit-Thukral A photo-transistor maybe better as it will draw less current in 'off' mode. Google phototransistor applications and there will be another learning opportunity for you ;)

        I Offline
        I Offline
        idanronen
        wrote on last edited by
        #3
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