Hi there,
first of all, wow what a fantastic project. I think this is what I need to create a prototype of an idea I have.

It's kind of basic. I need to create a script that counts up for each day and displays the number on a display. Also a button that can reset the number. But I need to know, for how long (I know it's just a guess) can the battery power the display, if it just have to show a number, and nothing else (the number changes each day, and thats it)?

This is the screen I'm talking about.
https://tinycircuits.com/collections/all/products/tinyscreen-basic-kit

I've been testing run times with the rechargeable battery. I am running the tinyScreen+ with the BLE board and the screen set to a brightness of 10. I was able to get 18 hrs on a battery before doing any power management/optimization.

You would not be running any comms (wifi, bt etc..) so your mileage should be better than that.

If you keep the main loop fairly empty, and redraw as little as possible (don't redraw on each loop, either check time, or even be super cheesy and do a count down, redraw) you should be able to stretch the battery out.

Hi Andy,
thanks a lot for the swift reply, it was a little less time than what I've hoped.