Let’s say I have en electron (asset tracker) that’s running off of external power (car battery) and has a small LiPo standby battery (100mah).
I’m putting the electron into deep sleep when the external (car battery) power is shut off. Is there a reasonable way to wake up the electron from deep sleep when the external power kicks back on?
I’m using a standby battery so I can publish an event after the vehicle is turned off. Obviously, if the standby battery is depleted during deep sleep, powering externally will reset the electron… but how can I handle it if the standby battery doesn’t die during sleep?
How are you detecting that the power from car battery is off ? How are the car battery and the LiPo connected to your Electron?
To wake up the Electron, you would want a rising edge on the WKP pin. The question is how to get a 3-5 volt level from your 12 volt battery. Check out this answer on StackExchange for some ideas on how to do that.
How are you detecting that the power from car battery is off ? How are the car battery and the LiPo connected to your Electron?
Car Battery -> Fuse -> Buck Step Down to 5V -> Electron, powered through Vin energized by "accessory" driven automotive relay. I also have a 100mah LiPo connected via the JST connector.
So... can I just run a "jumper" from Vin to the WKP pin, or am I misunderstanding how that mechanism works?