[Pre-Order] Safe Shutdown Switch (PowerBoost Version) - Closed
- Camble
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Re: [Pre-Order] Safe Shutdown Switch (PowerBoost Version)
@Mischief Don't worry, that pic is just for illustration. The board will come with no switch, or if you'd prefer, supplied with a switch.
- Mischief
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Re: [Pre-Order] Safe Shutdown Switch (PowerBoost Version)
No need for a switch just making sure I could hook it up to the DMG switchCamble wrote:@Mischief Don't worry, that pic is just for illustration. The board will come with no switch, or if you'd prefer, supplied with a switch.

Edit: Order placed

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Re: [Pre-Order] Safe Shutdown Switch (PowerBoost Version)
Ordered!
@Camble this is amazing! Thanks for making this happen. This project just keeps getting more and more interesting.
@Camble this is amazing! Thanks for making this happen. This project just keeps getting more and more interesting.
Re: [Pre-Order] Safe Shutdown Switch (PowerBoost Version)
How do you handle, script-wise, the low battery?
With my very limited electronic knowledge I can guess:
- LBO pin is pulled high to the VBAT on the powerboost when battery is not low so you connected it to the keepalive that is also high
- Low Battery RPI pin is also highas I see it connected to R1
- When LBO is dropped to 0 (battery level below 3.2v) what happens to the keepalive? My guess is that is pulled low. If that's the case then the low battery pin on the RPI is also pulled low, which we should be monitoring but it cannot work with Popcorn's version...
I see also that you have an R2 resistor to limit current from the LBO pin (mandatory as Vbat can go up to 4.2v which will damage the Pi), but I see also something that seems a diode on the 3.3V and that's when I think I get confused...
With my very limited electronic knowledge I can guess:
- LBO pin is pulled high to the VBAT on the powerboost when battery is not low so you connected it to the keepalive that is also high
- Low Battery RPI pin is also highas I see it connected to R1
- When LBO is dropped to 0 (battery level below 3.2v) what happens to the keepalive? My guess is that is pulled low. If that's the case then the low battery pin on the RPI is also pulled low, which we should be monitoring but it cannot work with Popcorn's version...
I see also that you have an R2 resistor to limit current from the LBO pin (mandatory as Vbat can go up to 4.2v which will damage the Pi), but I see also something that seems a diode on the 3.3V and that's when I think I get confused...
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- Camble
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Re: [Pre-Order] Safe Shutdown Switch (PowerBoost Version)
LBO does not connect to keep alive. These are effectively two separate circuits. You wire the LBO pin to the PowerBoost LBO pin, and the low-batt pin to a free GPIO pin on the Raspberry Pi. This pin will be set with an internal pull-down, so when a high signal is detected, you can execute some code. For example, @Popcorn's Power Monitor throws up a 60 second count-down then shuts the Pi down.keilun wrote:How do you handle, script-wise, the low battery?
With my very limited electronic knowledge I can guess:
- LBO pin is pulled high to the VBAT on the powerboost when battery is not low so you connected it to the keepalive that is also high
- Low Battery RPI pin is also highas I see it connected to R1
- When LBO is dropped to 0 (battery level below 3.2v) what happens to the keepalive? My guess is that is pulled low. If that's the case then the low battery pin on the RPI is also pulled low, which we should be monitoring but it cannot work with Popcorn's version...
I see also that you have an R2 resistor to limit current from the LBO pin (mandatory as Vbat can go up to 4.2v which will damage the Pi), but I see also something that seems a diode on the 3.3V and that's when I think I get confused...
Note: There is a mistake on the pin markings in the second photograph, the low-batt and keep-on pins are swapped. This has since been corrected.
Re: [Pre-Order] Safe Shutdown Switch (PowerBoost Version)
Thanks a lot, it makes much more sense now 

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