Robin2:
It should work fine on 4.5v from a pack of 3 x AA alkaline cells....R
I saw some people using these batteries so I got them, waiting to be shipped.
I did notice however, now that I added the relay to the circuit, that the relay tends to not work half of the time, I think the whole circuit is draining too much energy. Another notice is that if I just draw a full black background on the screen the relay works everytime (my screen always has a white background).
INTP:
Have you considered sleeping? Otherwise you're going to need analog circuitry to time 10 seconds.Can a phone scan the QR on that screen? Can you show which screen you have?
Yes, I did consider using sleep but from what I understand the board still drains power when sleeping so I think that turning it off completely is the way to go.
I am using this screen and yes, surprisingly my mobile app sees the qr code really fast 