Arduino Backup Supply

[brian25]

i want to interface this schematic to the arduino and this schematic works for AAA 6v battery backup but my problem is where to interface the triggering pin of arduino just to know when the main power is off. plss help.. tnx

 

[andre_luis]

Brian,


You could read 12V output sclaed by proper voltage divider.
However, I guess R3-D6 could be at same net as D3, in order to reduce power comsumption.


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[wp100]

Hi,

Are you are trying to recharge the batteries with that circuit ?

If not then think a simpler circuit like this would be better.

Using 10,000uf seems rather over the top, also you do not have any small caps around the regulators -see their datasheets.

You can take a line from the power supply as shown to an adc pin via a potential divider to act as a mains sensor.