Analog configuration on the puck.js?

Ok, great! So do you need to measure the frequency of every pulse, or just the amount of pulses in a minute (for instance)?

The nRF52832 doesn't have any timers (except the 32kHz real-time clock) that run when the device is in low-power mode, which makes the first option more difficult. I think at the moment we have:

1. Count the number of pulses, and then check every so often - very low power
   
2. Loop the comparator to an output pin, physically join that to another pin, and use setWatch on that to count using JavaScript and the RTC.
   
   

I've asked on Nordic's support site if there's another option - it might be possible to use the RTC to increment a timer 32k times a second.

Personally, if it's good enough, I think pulse counting would be the simplest and lowest power option.