Onoff shim with powerboost charger combination


#1

Hi.

Iam trying to have a raspberry pi zero running on battery and also have an option to do a complete shutdown (not the shutdown command, which brings it to a halted state), preferred through an power button.

I have been looking at a PowerBoost 500 charger to make the raspberry running on battery, and an on/off shim to turn the raspberry off, but i dont think i can combine these 2 and achieve the fuctionality of both?

If its not possible, can i use something else to achieve it?

Power Boost carger - https://shop.pimoroni.com/products/powerboost-500-charger-rechargeable-5v-lipo-usb-boost-500ma

OnOff shim - https://shop.pimoroni.com/products/onoff-shim


#2

I have a Powerboost 1000c in use in a couple of my Pi projects. What I did is wire a momentary switch to a GPIO PIN. And then program a shutdown when its pressed via a python script I run on bootup. Its maybe not ideal but it works. Then once the Pi shuts down I use second toggle switch to turn the Powerboost Off.

If you feed your power first to the Powerboost, thn plug that into the on off shim (mounted to the Pi) Both will work and the Pi will shutdown via the On Off Shim. Your Powerboost will keep running though and the battery will slowly run down if its not being powered by a power supply. Grounding the EN (enable).pin on the Powerboost will turn the upconverter off saving the battery. And if you have a power supply connected the charger will work and recharge the battery. That’s the way I do it. It just means having two switches / buttons.


#3

Thanks for the reply, i actually think iam going to copy your approach and do the same.


#4

The 3B and 3B+ will boot up if you ground pin 5 on the GPIO. And I do believe there is a config.txt edit to make it do a normal shutdown when you ground that pin. No need for the on off shim. Power isn’t removed though, as thats needed for it to boot up when you press the button.

You add the following line to /boot/config.txt:

dtoverlay=gpio-shutdown


#5

If you watch the latest Bilge Tank video they hint of a new device thats in the works that may well do what you want. It’s mentioned towards the end of the video.

I would think the same pin grounding on off function will also work in the new 3A+.


#6

its around 8:30 i think ,sounds interesting.
i have onoff shim and pHATDac working together,but not with the powerboost,maybe i;ll try that see what happens


#7

The on off shim will shut down Raspbian, and then kill power to the Pi. No power by battery support though.

The lipo shim will let your Pi run off of battery if the power in fails, but can’t recharge the battery when it comes back. You have to unplug it and plug it into a charger to recharge it.

The Powerboost can’t turn off or shut down your Pi. But will let it run off of battery if the power in fails. And recharge the battery when it comes back. It can be turned off manually via the enable pin.

It sounds like this new product is an on off shim and lipo shim in one unit. If it has a battery charger circuit it will do all of the above, lol.


#8

Just watched the video again, they mention a LIPO “charge” Shim. So I guess its a LIPO shim that can recharge the battery. Their version of the Powerboost?
And then a mention of a Pi Power pHat? No mention of what it will do or not do, Stay tuned I guess.


#9

I think it sounds like they are cooking up what i wanted. But yea have to stay tuned to find out.

also my little project is actually only going to run an application that will end in either a succes or fail. so your original idea is going to work perfect for me, because i can send a shutdown commad at the end of the application, and then hook up a power switch to the gnd- and the EN(enable).pin on the the powerboost charger. That way i will make it work with only 1 button.


#10

About my only complaint with the Powerboost is the 1A out limit. Thats pretty iffy if its a Pi 3B or 3B+. My PowerBoost’s are only powering Zero’s and A+'s. And mine are all running headless. No display to have to power along with the Pi.

My shutdown code is just rolled into the python file I’m already running on boot.


#11

this is what i had plans of doing with the 500 i got ,just never got around to doing it yet ,winters coming maybe one day .


#12

Thats actually a quite cool project, nostalgia ftw :)