Darian Johnson
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)]
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@K.C. Lee - Thanks for your comment - I'm definitely planning to use the LIR versions (I should update my documentation... I used CRXXXX instead of the correct name). I'll let you know how it goes.
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The rechargable version (LIRxxxx) would be more suited than the disposable ones (CRxxxx).
The CR internal resistance is too high when you need more than a few mA and t loses too much capacity that way. You could help a bit with low ESR bulk caps, but much better of using that volume for larger Li-ion battery.
https://www.dmcinfo.com/Portals/0/Blog%20Files/High%20pulse%20drain%20impact%20on%20CR2032%20coin%20cell%20battery%20capacity.pdf
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