Automatic turn off after 1 hr or btn push

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Roger_A
 
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Automatic turn off after 1 hr or btn push

Post by Roger_A »

I have a project when I need a single button to turn on power to the Nano, and by pressing the same button trigger a shut-down routine (e.g. to close files) and then turn off power. I also need an automatic shutdown after 1 hr.
It looks like the Adafruit TPL5110 does everything I want, except, I need to set the recycle time to a very long period, i.e. never recycle automatically. Is this possible?
Any suggestions would be appreciated.

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dastels
 
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Re: Automatic turn off after 1 hr or btn push

Post by dastels »

The TPL5110 won't do that. It's has a button to turn it on and will turn on at a certain frequency (up to once every 2 hr) and turn off with a signal on its DONE pin (typically from an MCU it is controlling).

I'd start by considering a flipflop to control the power (see https://learn.adafruit.com/digital-circ ... flip-flops). A button would be used to set it as well as connect to a input pin to be read by the controlled computer. An output pin would be used to reset the flipflop to disconnect power. Then some time interval expires or the button is seen to be pressed, the shutdown sequence would be executed, culminating in resetting the flipflop.

Dave

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MDCB
 
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Re: Automatic turn off after 1 hr or btn push

Post by MDCB »

I have a similar question: I'm looking to constantly repeat a cycle in which power toggles ON for a duration of 10 minutes, and then power is toggled OFF for an hour, forever. The idea would be to have the TPL5110 sit between the battery and the hardware.

However, I'm unable to pass a signal to the DONE pin (I can't interact with the hardware to wire anything); is there a way to have the TPL5110 automatically cycle OFF based on a timer interval?

Alternately, is there a better option of a small timer that can constantly cycle based on this schedule? Thanks!

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dastels
 
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Re: Automatic turn off after 1 hr or btn push

Post by dastels »

I'm looking to constantly repeat a cycle in which power toggles ON for a duration of 10 minutes, and then power is toggled OFF for an hour, forever. The idea would be to have the TPL5110 sit between the battery and the hardware.
That's what the TPL5110 is for, and how you use it.
However, I'm unable to pass a signal to the DONE pin (I can't interact with the hardware to wire anything); is there a way to have the TPL5110 automatically cycle OFF based on a timer interval?
This is more challenging. The TPL5110 needs DONE to go high for it to turns off its output. You could add a circuit (probably a resistor/capacitor circuit connected to DONE) that would take DONE high after 10 minutes. When power was output from the TPL5110, a capacitor would start charging and would take 10 minutes to reach a voltage that is seen as high by DONE. The other option is to have a small MCU board (a QTPy M0 for example), also powered by the TPL5110, that would do nothing but wait for 10 minutes and then take DONE high.

Dave

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