Water flow meter / totalizer with nrf51822

[gio]

Hi all, I would like to measure water consumption at my home with nrf 51822 and send it over bluetooth. I know there are some flow meters generating pulses, but how can I count them with lowest battery drain. I would like my battery to last 10 years or so on, by minimizing both measures and bt transmissions(even one every hour is acceptable)

[gio]

Hi, thanks for the pointer, sounds very interesting for other ideas I have, where sensors can be activated, measured and deactivated upon request. In water totalizer case instead, I have to deal with flow sensors, made by third parties, which are always on and continuosly measure the water flow. I know these sensors emits pulses, thus I need a way to count these pulses using Nano in a very low-power way.