“LowPower Arduino Countdown Timer
Features:
- the timer is always enabled and remains ready in deep sleep mode
- low power modes used as often as possible to save energy
- 500mAh LiPo cell should last for 2-3 years depending of how often the timer will be actually used
- backlight typically is used only for 15 seconds, can be removed completely
- deep sleep counter is used in countdown mode to save energy, it is not very accurate, can be replaced by regular sleep in case of issues
- could’t decide which font should be used so finally there are 4 looks (4 fonts, 2 progress indicators)
BoM:
- Arduino Pro Mini
- HX1230 96x68 pixel LCD
- button
- buzzer or mini speaker
- 100ohm resistor - 2 pcs”