TPL5110 Usage Moderators: adafruit_support_bill, adafruit

[benvien]

I bought a few TPL5110s to help manage power usage for some coin cell operated projects. What I need is for a pushbutton to activate power to the Arduino, then wait for a Done signal and kill power until the pushbutton is pressed again. I thought that's what the TPL5110 could do, but it seems there is no way around the timer trigger. Is there anyway to disable the timer trigger?

[dastels]

No. Not in my experience. With the chips, yes, but not with how it is connected on the breakouts. When I need the behavior you describe, I put a timeout in the code. One of my projects is a coffee/tea timer and after pressing the button to turn power on, the user presses one of two other buttons to select tea or coffee. If neither is pressed after some short time (10 seconds I think) it triggers DONE and goes back to sleep. Then I set the delay to the longest possible. The result is that it will wake on its own every so often, wait a bit and go back to sleep. I don't know if that approach will work in your case.

Dave

[benvien]

Thanks, that confirms my findings. I think your idea of just setting the delay to max might work.

[benvien]

Dave,
While researching building my own 'soft latch' I came across this gem which appears to do exactly what I'm looking for. Do you think this will do the trick?

Adafruit Push button Power Switch: https://www.adafruit.com/product/1400

No. Not in my experience. With the chips, yes, but not with how it is connected on the breakouts. When I need the behavior you describe, I put a timeout in the code. One of my projects is a coffee/tea timer and after pressing the button to turn power on, the user presses one of two other buttons to select tea or coffee. If neither is pressed after some short time (10 seconds I think) it triggers DONE and goes back to sleep. Then I set the delay to the longest possible. The result is that it will wake on its own every so often, wait a bit and go back to sleep. I don't know if that approach will work in your case.

Dave

[dastels]

Right. That takes care of turning it on. The KILL input will take care of turning it off But you'll still need a delay to let the Pi finish shutting down cleanly before power is cut.

It's the flipflop and FET in one nice package. One potential problem, though: pressing the button when power is on will turn it off without giving the Pi a chance to shutdown.

Dave