Low Power LED detection : Voltage Divider or RC Time?



  • 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



  • @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 😉



  • This post is deleted!

Log in to reply
 

Suggested Topics

7
Online

9.4k
Users

10.0k
Topics

104.3k
Posts