I'd like to get 3-4 days of use from the wearable; my assumption is that the MCU will stay in a deep sleep mode, unless 'interrupted' by the RTC (alarm/reminder) or push button (record an event).
I'd also like to go with a small battery. A LIR2032 or LIR2035 coin cell would work - except that I believe both are two large in diameter for the bracelet (they are 20 and 23 mm). The LIR1220 is a better option size-wise (12 mm) - I just don't know if:
- It will allow enough current to drive the haptic motor
- it will recharge in an adequate amount of time
- It will last 3 days assuming 20 alerts/events a day
Next step is to put together a quick proof of concept to validate my assumptions.
[Note - I originally referenced the wrong version of the batteries (CRXXXX instead of LIRXXXX)]