Watch

A belt clip digital watch. This will be a good smd test. Probably want to order a board.

V1

Hardware

Screen will be the Nokia 5110. I'd like to get just the screen, not the whole module, but I can't seem to find that. Possibly disassemble one, though I can't even find a reference to that.

Use a DS3231 real time clock IC.

MCU will be AVR.

Need a small buzzer.

Interface could probably use a rotary encoder to reduce the number of buttons needed

Power can be a li-ion cell. This needs a charging IC and a usb port to charge.

Maybe add solar cell to charge it?

Software

The AVR will be in sleep mode most of the time to reduce power consumption. It only wakes up occasionally to update the display.

Basic function displays the date and time. A nice touch would be to display unix time.

Can add multiple timers.

Can add multiple stop watches.

Can add multiple alarms.

Possible Extensions

1W LED to use as flashlight

Adding a laser diode would be nice.

Temperature sensor.

Add photoresistor and when it's dark, turn off the display.

I could get a pocket watch case and mount it inside. It would be cool if I could get a rotary encoder connected to the watch knob.

Pocket Watch

More of "someday".

Pocket watch case. Inside are two displays. What would normally be the winding mechanism is the interface (via a rotary encoder). When the watch is closed, it's in a low power mode. When it's opened, it turns on.