Project Guidance: Resistive or capacitive sensor?


I recently purchased an Electric Imp module and I want to build a moisture monitoring system for some indoor plants that i have. The problem is I don't know what type of sensor should I choose: capacitive or resistive? I found some potential candidates:



The whole idea is which is easier to implement? I understood that the resistive one has some issues of humid readability. And the capacitive has some issues of calibrating.
Also, I am kinda new at this.

Thank you in advance.

I have not used either. but in reading about the capacitive ones, it seems that the cheap ones drift.

I would offer that the cost of these parts are so low that you should try both. find out if soil types have effect. find out if people walking or working nearby have any effect.

Probably more out of familiarity than anything else, I'd go with resistance. It's simple, tried and trusted technology.

Capacitance is simple enough to setup for things like touch sensitive switches, but to get something quantative out of them. I wouldn't even know where to start.

Thank you for your replies. Keep them coming :smiley:

here is a place to start :

I made 4 resistive probes myself from old computer motherboards. On the edge of one of the old motherboards, I found two parallel traces about 3 inches long. I cut the motherboard around those traces and sanded the protective green covering to expose the traces. Soldered leads on the traces, and tested with a attiny85 and it works great! I then protected the traces with a thin coating of nail polish and re-tested to get the constraint values.

These work great for water level sensors and soil moisture sensors. An attiny*5 avr chip and a rfm12b transceiver and you got yourself a great way to monitor your plants around the house/yard.