Tackling Graceful Shutdowns on the GBZ

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SidSilver
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Re: Tackling Graceful Shutdowns on the GBZ

Post by SidSilver » Fri Jul 15, 2016 3:48 am

Camble wrote:
SidSilver wrote:Very interesting.
I've done the Popcorn Pololu solution, it's nice but need a switch to poweroff the powerboost when not used.

If I understand what you are working on Camble, it seems better as the powerboost is switched of automatically.
The monetary switch works very well. Hold the button for a few seconds and the Pi boots. Everything shuts down cleanly as you'd expect. The problem is only due to the slide switch. If you were to continue to hold the power button, the charging LEDs on the powerboost go haywire. That can't be a good state for it to be in.
Have you try the low battery poweroff ?
Last edited by SidSilver on Fri Jul 15, 2016 3:56 am, edited 2 times in total.

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Re: Tackling Graceful Shutdowns on the GBZ

Post by Camble » Fri Jul 15, 2016 3:54 am

@SidSilver Not yet. Been battling with this for ages :lol:

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Re: Tackling Graceful Shutdowns on the GBZ

Post by SidSilver » Fri Jul 15, 2016 3:57 am

@Camble : I mesured LBO output at 5V, isn't it too much for GPIO ?
I thought GPIO support 3,3V only => 5V will definitely damage the GPIO

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Re: Tackling Graceful Shutdowns on the GBZ

Post by Camble » Fri Jul 15, 2016 3:58 am


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Re: Tackling Graceful Shutdowns on the GBZ

Post by SidSilver » Fri Jul 15, 2016 4:07 am

Camble wrote:@SidSilver True, but http://tansi.info/rp/interfacing5v.html
Sorry I don't understand everything
I our case, if you look at his schema, just the 1kohm resistor is enough ?

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Re: Tackling Graceful Shutdowns on the GBZ

Post by Camble » Fri Jul 15, 2016 4:09 am

I think the diode and 3.3v line is important. It will limit the voltage to the GPIO pin.

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Re: Tackling Graceful Shutdowns on the GBZ

Post by SidSilver » Fri Jul 15, 2016 4:14 am

Camble wrote:I think the diode and 3.3v line is important. It will limit the voltage to the GPIO pin.
I've found a better solution I think
https://learn.sparkfun.com/tutorials/vo ... viders/all

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Re: Tackling Graceful Shutdowns on the GBZ

Post by Camble » Fri Jul 15, 2016 4:17 am

That's what I'm using on my breadboard, but I thought the link would be more useful.

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Re: Tackling Graceful Shutdowns on the GBZ

Post by Quatrerwin » Fri Jul 15, 2016 6:50 am

I can't wait to attempt to put it together. I have a couple of ideas to try to get it to work. Though I still can't figure out how the MOSFET does that to the powerboost considering the drain to source circuit has a break in it when the switch is on. I'm wondering if you need to add reverse voltage protection on the drain side of the MOSFET for when it's active. Looks the the Pololu adds a 6.8V diode for its reverse circuit protection.

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Re: Tackling Graceful Shutdowns on the GBZ

Post by Camble » Fri Jul 15, 2016 7:02 am

@Quatrerwin I've been told it's something do with capacitance across the pins. A little research revealed it's good practice to include a pull-down resistor across the gate/source. I'll test this out tonight.

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