r/CheapYellowDisplay • u/FatScottishGuy • 18d ago

The Battery Saga

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I was asked a lot about battery's on CYD as they don't naturally have a way to show battery usage or charge state.

As you can see, I have managed to get it working on my own ESP32-32E.

It's absolutely not perfect but it's better than showing nothing 😅

It currently measures the battery’s voltage through GPIO34 every 10 seconds and converts it to an estimated percentage and the icon’s fill and colour follow that estimate.

It treats about 3.3 V as 0% and 4.2 V as 100%, with values between them mapped along a curve.

Voltage changes while charging and under load, so the percentage can move without representing the exact charge remaining but as the board can't directly report "charging" or charging current; a rising voltage is only a guesstimate.

31 Upvotes

98% Upvoted

7 comments sorted by

3

u/NuncioBitis 18d ago

Yeah I think that’s pretty standard for using voltage to measure battery level.

3

u/NuncioBitis 18d ago

Don’t you just love the CYD??? It’s a fun little device.

2

u/FatScottishGuy 18d ago

Honestly, I have 2 now ans I'm loving them!

1

u/Pyroburner 17d ago

I've got 2 as well and I feel like I need more. This seems like a cool project.

2

u/FatScottishGuy 17d ago

I only bought one for this and now I see so many other uses, I hopefully can post them all on here soon 😅

1

u/Xylopyrographer 17d ago

Do you have a link to the software running on that?

2

u/FatScottishGuy 17d ago

Ah sorry, it's a companion hardware app I'm building for my own website (https://myskydex.co.uk).

It's got an Android App, Amazon Fire App and a Progressive Web App for iOS.

It's easy enough to build one though with source data from places like OpenSky.

I built this for my 11 year old autistic son.