Hi there.
I would like to make a bluetooth hydrometer for my homebrewing hobby and need a microcontroller that can work up to a month on battery power.
It is a simple device consisting of a microcontroller and a battery in a sealed container that floats in fermenting liquid. As the gravity of the liquid changes the device changes its floating angle and all I need is to be able to read this value on my phone. The readings can be taken on one hour basis.
Can the XIAO nRF52840 Sense be used for this?
I have a Li-ion battery of 700 mAh. Can this work for a month?
Kind regards.
Danijel
Hi there, and Welcome.
DanKapLu , the XIAO nRF52840 BLE Sense can do that easy and is able to sleep and save tremendous power. There is an Online battery life calculator, HERE
Based an a 700mah Battery @ asleep current of 44ua. you would get approx. 2 MOS 1 WKS 5 DAYS 15 HRS 0 MIN.
Albeit YMMV depending on the true load and power profile. easily calculated with a code example and power profiler.
HTH
GL 
PJ
PJ_Glasso,
thank you for the reply.
Is a li-ion battery approtiate for the seeduino or does it have to be a li-po battery?
I plan to charge it sepparetly on an external charger.
Looking forward to purchase the board. This is going to be a nice Christmas vacation project.
Hi there, Sure that will work, Indeed it’s a fun project especially if it leads to good Beer 
LOL
GL PJ
Thanx for the info.
I’m really glad I stumbeld upon this tiny board. It has all I need in a small package so it fits in a smaller petling and no need for extra components like gyroscope or voltage regulator.
Will post when it is finished.
Kind regards.
Danijel
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