AVR-Chat

aila_alizadeh wrote:
> hi everybody:
> does anybody have information about humidity sensors with 2 pin ?
> I just know that they act as a capacitor ,but I don't know how I 
> should measure it ,and how I should do that with avr .
> whould you mind sharing your experience about that with me ?
> If you send me any useful information about measuring & calibrating 
> these sensors and build a hygrometer ,I'll be very 
> 
> thankful.
> Aila Hasanalizadeh

Go here:  http://www.linear.com/designtools/app_notes/index.jsp

Look for and download Application Notes AN3 and AN7.  Both appnotes 
show a humidity sensing and signal conditioning circuit.
AN3 figure 8 shows a circuit which delivers an analogue voltage, while 
AN7 figure 11 shows a circuit that delivers a variable frequency.


erikc
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