SDK 15.2: Recommendation on accurate SAADC readings of moisture sensor over time

[tBStar]

Hi,

I am sampling a moisture sensor using one of the analog pins without issues. However, since my circuit is battery powered, I need to account for voltage drop of a 3V coin cell. The question is how do I compensate for the voltage drop while the battery is draining? Do I base the readings while taking the battery voltage in consideration?

Thanks

[tBStar]

I get your point, I was trying to use a sensor that was meant to be used with a micro controller such as Arduino. I am thinking to redesign it in a way that I could run the signal coming out of the rods through an OpAmp then read the rising edges with GPIOE peripheral directly without involving the CPU. Do you think it will work?

Thanks 

[hmolesworth]

Yes, that will work. As an added advantage with digital you gain remote operation without adverse interference effects which are a major issue with analogue. In the extreme, you can split a single-ended digital signal into a differential signal using (say) an RS485 driver; that provides remote operation for hundreds of metres (yards) and - given a low enough data rate - over multiple furlongs. However the cable cost would then swamp the other system costs so better to just use BLE as you are. Digital over even 2 metres (6ft) works better than analogue (in general).