Benjy's Prototype Wristwatch

In 2015, I saw the MicroView OLED Arduino Module at SparkFun. One picture showed an analog clock dial which made me think the module might back a nice replacement for a traditional watch. So I created a prototype watch. After seeing how large the unit and corresponding circuit board was, I abandoned the project before designing a 3D case. However, I did complete the software for the project.

The parts for the watch are

MicroView Module
Lithium Ion Polymer Battery - 3.7V 150mAH
DS3231 Real Time Clock and CR1220 and Holder for Battery Backup
Connector for the Lithium Battery
Momentary Switch
Custom PCB

Image Function Period Until Sleep Short Press Long Press

Time 10 seconds Date Set Mode

Date 10 seconds Picture Set Mode

Picture 10 seconds Stop Watch Set Mode

Stop Watch -- Pause/Continue Sleep Mode

Function	Period Until Sleep	Short Press	Long Press
Time	10 seconds	Date	Set Mode
Date	10 seconds	Picture	Set Mode
Picture	10 seconds	Stop Watch	Set Mode
Stop Watch	--	Pause/Continue	Sleep Mode

During normal operation, the display is blank, and the Arduino is in sleep mode to conserve battery life. One short press of the switch takes the watch to time display mode. After 10 seconds, the watch goes back to sleep. A short press during time mode causes the watch to display the date. The date is displayed for 10 seconds. A short press puts the watch in picture display mode where it displays a picture of Squeaky the cat. A long press in any of these modes puts the watch in setup mode. A short press in picture mode puts the watch in stop watch mode. A short press toggles between updating the time and pausing the time. A long press puts the watch back to sleep.

In setup mode, the watch is set up via the USB serial interface. The MicroView is unplugged, the serial programmer is plugged in its place, and the MicroView plugs into the serial programmer. In set mode, the lithium battery is unplugged and the watch is powered from the USB programmer. The time and date are sent to the serial port from a computer in HHMM MMDDYY format. Then a blank is set when the time is to be updated.

Battery life seems reasonable as in normal use the battery charge will last for weeks. Unfortunately, in order to recharge the battery, the watch must be partially disassembled.

I had fun building the watch and creating the software and PCB. It just wasn't practical for a watch due to its size and fragility.