[Gauging Interest] Safe Shutdown (BangGood edition)

johnny-bert · Post by **johnny-bert** » Sun Sep 18, 2016 10:08 am

Is it possible to adjust shutdown voltage with this board?

Camble · Post by **Camble** » Sun Sep 18, 2016 2:52 pm

johnny-bert wrote:Is it possible to adjust shutdown voltage with this board?

Can you elaborate?

johnny-bert · Post by **johnny-bert** » Sun Sep 18, 2016 3:36 pm

No, I can't. Sry, but I'm not a professional in electronics.
What voltage will be the shutdown voltage?

Camble · Post by **Camble** » Mon Sep 19, 2016 2:36 am

@johnny-bert If you mean the voltage on the GPIO pin, 3.3v

Fleder · Post by **Fleder** » Mon Sep 19, 2016 3:19 am

Camble wrote:
johnny-bert wrote:Is it possible to adjust shutdown voltage with this board?
Can you elaborate?

I think he want's to know if he can choose the voltage at which the Pi would shutdown.

Camble · Post by **Camble** » Mon Sep 19, 2016 4:26 am

Fleder wrote:I think he want's to know if he can choose the voltage at which the Pi would shutdown.

Ah! Good spot.

I measured the supply voltage of the BangGood supply as 5.1v and set up reference voltage to exactly 3.2v accurate to 1%. It would only be adjustable by removing and replacing the resistors.

You can add a software delay in your power monitor script if you want more time before shutdown.

@johnny-bert Is an adjustable low battery voltage something you require?

johnny-bert · Post by **johnny-bert** » Mon Sep 19, 2016 6:01 am

Hi,

for me personally, it's important, because I'm using NiMH-batteries.

So I would like to adjust the shutdown-voltage.

Adjustment possible through changing resistors (with resistors or potentiometer) -> GREAT!

Fleder · Post by **Fleder** » Mon Sep 19, 2016 6:08 am

You can swap out the resistors for one of those: http://www.taydaelectronics.com/potenti ... r-6mm.html

This would make it possible for you to adjust it with the help of a MM and a bit of testing.

johnny-bert · Post by **johnny-bert** » Mon Sep 19, 2016 6:37 am

So all resistors would have to be changed or only a single one?

Camble · Post by **Camble** » Mon Sep 19, 2016 7:02 am

@johnny-bert Two, actually. The reference voltage is set with a voltage divider. In this instance, a 20K and 33K resistor are used. What voltage would you need set?

[Gauging Interest] Safe Shutdown (BangGood edition)

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