OnOff-Shim


#1

ahoy!, this is awesome - https://shop.pimoroni.com/collections/raspberry-pi/products/onoff-shim

and i want to use it for my solar powered radio which i am using the adafruit powerboost 500 basic to also initiate shutdown when the PIN 4 is pulled low.

BAT but when the charger detects a low voltage (under 3.2V) the pin will drop down to 0V. You can use this to signal when its time to shut down or alert the user that the battery is low.

in your info you state the following

We’ve put together a one-line-installer to install the clean shutdown daemon. It watches the state of BCM pin 17 and, when pulled low (pressed), it initiates a clean shutdown. Last thing, just before your Pi shuts down, BCM pin 4 is pulled low to completely cut power to your Pi.

can i use the same pin in conjunction with this OnOff-shim ?


#2

If both are watching BCM 4 for a low then as soon it is triggered low both will complete their functions.


#3

ok thanks ill test it out later :)


#4

if I understand the question, those add-ons will be monitoring different pins though, the powerboost bcm4 and the SHIM bmc17.

… I’m not really clear on how the functionality are intended to work together in your setup though, so hard to say whether that will be OK or create problem (when bcm4 goes low due to powerboost).


#5

hiya, the powerbooster just sends a pull low signal to the pin 4 which then initiates the shutdown im using your https://github.com/pimoroni/clean-shutdown?files=1 script to do this.


#6

my question was more: how do you expect the 2 boards to inter-operate?

… right now, the powerboost will initiate a shutdown when the battery drops below 3.2V. The OnOffShim will initiate a shutdown via physical action of the button.

Presumably you are only connecting power via the power boost though? so I’m unclear what benefit you gain out of the SHIM in this scenario (that you could not obtain with a simple button input)?


#7

I would like to breakout the onoff shim connections. I assume from the earlier reply:

“We’ve put together a one-line-installer to install the clean shutdown daemon. It watches the state of BCM pin 17 and, when pulled low (pressed), it initiates a clean shutdown. Last thing, just before your Pi shuts down, BCM pin 4 is pulled low to completely cut power to your Pi.”

That I will just need to connect 5v to a 5v pin, gnd to gnd, BCM17 to BCM17 and BCMpin4 to BCM4. Can you confirm that none of the other pins are required, other than perhaps soldering connections to the micro-switch connection for use a nice lit momentary switch in its place.


#8

Hi did you figure this out? I’m currently using a Powerboost 1000c with an On/Off Shim. I have the 5v (USB) power running to the Powerboost, then the power boost feeds the power to the On/Off Shim (instead of directly to the Pi).

I’m using the PowerBoost to handle powering (from 5v usb, or battery) and charging the battery. I’m using the On/Off Shim to handle clean shutdowns and my devices power button is hooked up to it.

I haven’t tested to see if it just auto-magically shuts off the pi on low battery (I don’t think it does?), so that may be issue #1.

Also, issue #2, the powerboost itself always thinks it’s still on (because, well, it is). The power gets cut on the next part of the circuit (on/off shim) so the Powerboost still has it’s LEDs active. What’s the best way to wire that up to switch on/off the powerboost too?

Thanks