Posts: 2
Joined: Thu Apr 19, 2018 11:49 am

Start Up Shutdown Button

Thu Apr 19, 2018 12:46 pm

Hey guys,

need your help for a start up and shut-down push-button. There is an easier solution with waking up the Pi with GPIO 5 and switch off with the same port by a short python script. But there is a problem: It shouldn´t start with connecting the power supply.

I had an idea with an thyristor. Using a push-button to ignite the thyristor. And afterwards a python script is going to shut down the Pi due to the next status of the button... But, there arise a few questions:
- The Pi still needs some Ampere during switched off. With which Thyristor it´ll change even though to the blocking state again?
I think the current is still to high to get a tiny thyristor for it??
- Does my circuit in attachment makes sense to solve this?
- Maybe there is another idea? without an external micro controller?

Thanks from Germany already :)

StartupShutdown2.png (247.74 KiB) Viewed 226 times

Posts: 2
Joined: Thu Apr 19, 2018 11:49 am

Re: Start Up Shutdown Button

Wed Apr 25, 2018 5:35 am

Got a solution with a LTC2954 for instance.
Therefore is a problem. The Pi has to show the LTC2954 that he started within 512 ms with pulling the KILL pin to HIGH.

Is there a possibility, a GPIO changes within 512 ms its status during booting?

After shutdown the Pi has to Pull it to LOW again for removing the supply voltage by the LTC...

best regards


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