Simple low battery indicator

[ninertriplezero]

I've just started putting my GBZ project together, and last night connected the 3.5 inch screen and pizero to 4 rechargable AA batteries in the GB original battery holder, and it worked!

I'm still really shocked it worked first time as I've not done anything like this before, but I need a bit of help with the next step!

I'd like to add a low battery led indicator to show when the batteries are running down and the system needs to be turned off.

I'd also like to be able to connect the system to the mains supply as an alternative, but I will charge the batteries separately. How do I deal with this and a power switch? Do I need a switch to toggle between the two power sources?

I'm not bothered about an automatic shutdown or anything too fancy, I'm happy to shut down the system through the menu then turn it off manually, I'd just like an led that turns on when the battery is too low. I know most people on here use the powerboost, but as I'm just using AAs I don't think I really need that?

Any help would be much appreciated!

IMG_2286.JPG (93.41 KiB) Viewed 10549 times

[Helder]

Already got one made:

http://www.sudomod.com/forum/viewtopic.php?f=3&t=1107

[ninertriplezero]

That looks great. Is there anywhere I can get one from the UK? Don't want to receive a customs charge if they stop it.

[CaptainDurden]

That looks great. Is there anywhere I can get one from the UK? Don't want to receive a customs charge if they stop it.

there's no way you'll get charged for customs for 3 quid worth of stuff. EU regulations differ from country to country, but below a threshold of around 18 quid/ 22€ you should not have any trouble with either custom tax or import VAT.

[Zero]

Just a word of advice on using AA's. I tried that for one of my builds and it drained one battery over the others when in series, which means they don't last very long. 3x Eneloops lasted about an hour for mine. I suggest you look into using parts from a powerbank which has a low power led indicator built-in already, some are cheap as chips, and will save you some wiring. You can also recharge the batteries while they're still inside the device that way if you wire it up properly. You can't charge while playing though. They also have overcharge protection, etc, so less stuff to have to buy extra too.

[ninertriplezero]

CaptainDurden

I'll probably give it a go if I continue with AAs, thanks

Just a word of advice on using AA's...I suggest you look into using parts from a powerbank...

That was my original thinking, but I really liked the neatness of using the original battery compartment and wanted to try it first. I didn't even expect it to power on so it's already exceeded my expectations

I'm a bit wary of dismantling batteries as I have no experience in it and don't want anything to explode! Maybe I could find one small enough to fit in without taking it apart? I'm happy to charge it separately.

[Camble]

If you're using the GearBest/BangGood power supply, my Safe Shutdown board includes a low battery indicator. It doesn't illuminate an LED though, it connects to the Pi and works with @Popcorn's power monitor to warn you and automatically shutdown.

http://sudomod.com/forum/viewtopic.php?f=3&t=1418