This being my first post, let me start of with saying hello to all of you!

Im working on an automation project at my university where we are tasked to build a system for monitoring the temperature and humidity in a sauna. The measured values will be input signals which will regulate the temperature by heating up the sauna and the humidity by automatically sprinkle small doses of water on the heater.

At the moment we're stuck on the humidity part, as we're not sure how to assemble it. We've got the SMTHS07 to work with. Is there any of you on this forum sitting on a schematic for such a sensor or have any suggestions where we might find one?

Thanks in advance for any input,
Karl

 

Welcome to AAC.

Microchip has an old application note on measuring capacitance change, but it would need adjusting for the pF changes that sensor produces:

http://ww1.microchip.com/downloads/en/AppNotes/00611b.pdf

I have not tried the Microchip circuit. I have used the Analog Microelectronics' CAV 414 detector. It should work in that range. AME makes a series of such specialized IC's, so you may want to go to its site and browse.

http://pdf1.alldatasheet.com/datasheet-pdf/view/197607/AME/CAV414.html

http://www.analogmicro.de

John