Accessory is: Automotive fan controller on Nano (circuit below)
I would like it to stay powered when ignition turned off for a minute, and I would like the power draw to be < 2 mA when not in use.
Separate Arduino to act as a power gate from battery to the buck converter with timer triggered by ignition. Smaller unit the better, be nice to pack it in. My only experience is Nano, it draws too much current even with LED cut out.
- What Arduino to consider for the power gate and what is sleep current draw?
- Gated power direct through pin, or transistor? np2222? (LED is 14mA, no idea how much serial to OBD draws)
Thx.
http://www.gammon.com.au/power was very helpful for me. Build your own barenones arduino to save most you want.
But still why? Your car battery can run your arduino for ages without troubles. I have a powerhungy easpberry pi running 24/7 on my car battery.
Bringamosa:
Gammon Forum : Electronics : Microprocessors : Power saving techniques for microprocessors was very helpful for me.
That info is awesome, thx. I'm surprised that didn't turn up in all my clicking.
Bringamosa:
But still why?
The fan I'm running is out of a Mercedes. It has it's own mosfet unit with 2 4awg heavy wires for fan motor which would not draw any current. But it also has 2 each 22 awg wires. One is a power signal from ignition and the other requires a pwm signal which I'm sending from this Arduino. It always requires a PWM signal at 10% duty cycle for fan not to run as long as the other has power otherwise it has failsafe mode to turn fan on full blast. So that gets a little more complicated. Perhaps if the 22awg power signal to fan can run from 5v and < 200mA, then I can power that from another pin on this Arduino and keep it all in one unit. I should be able to get away with it, but I sure like the idea of gating the whole operation and powering down ultra low like that article you shared.
I also want to keep the car power (ignition signal to trigger timer) off of the board as it has noise and I'm not sure if I'd be asking for trouble.
I'm not sure how much current the buck regulator draws on it's own when Arduino asleep?