So I am making a digital pocket watch that will most likely use a custom PCB and run off of a lipo battery (this one specifically LiPo Battery Pack - Pimoroni). Don't worry about packaging as I have an idea for that. I just would like a few people to take a once-over at my schematic to point out any errors for me. This is my first circuit design but I (at least think) I know my way around Arduino and other programmable micro-controllers.
Not sure what some of the parts do , but noticed ā5vā . The Lipo is 3.7 volts , why not run everything at 3.7 volts ?
I think Iād remove the battery protection and use an off board proper li charger . You only then have to worry about low voltage .
Power consumption is a big issue - try to get resistor values as high as possible .
Decoupling caps ?
You could switch off the whole watch inc display and only power it via a push button to read the time .
You might then get away with a coin cell eg CR2032? Or maybe running it all off the RTC battery ? ( you can get rechargeable versions of the RTC battery .)
I would do some experiments on breadboard before rushing into PCB.
Thanks, I'm planning to make it go into a 'sleep' mode after something like 30s of the encoder being moved.
I plan to replicate the time setting 'procedure' of a normal pocket watch, where you pull the knob up and then rotate it to set the time. I subconsciously rotate the knob whenever I read the watch because it also winds the watch when not in the time setting position
Yes but the display will still be powered and if you only have it on for 2-3sec you save a lot more power. If you turn everything off , it uses no power at all
I was also looking at a monostable ne555 circuit controlling a power MOSFET. Do you think it would be a better (and easier) design?
Also you're right about it just running 3.7 volts now I think about it. The whole reason I chose the 85v was because it can run smoothly until 2.8ish v
