Humidity sensor

[Chris Fowler]

I'm looking for a schematic that will allow me to build
a humidity sensor and attach to me serial port. I'll then
write software under Linux to read the port and display
meaningful data. Any links?

Thnaks,
Chris Fowler

 

[Lord Garth]

I'm looking for a schematic that will allow me to build
a humidity sensor and attach to me serial port. I'll then
write software under Linux to read the port and display
meaningful data. Any links?

Thnaks,
Chris Fowler

Humidity sensors are generally capacitive. You could use
one to vary the frequency or pulse width of an oscillator
which you would then count or time.

If you really want to build the sensor, you might try something
that shrinks or expands in response to humidity....human hair comes
to mind.

 

[Henrik Nielsen]

Hi
Look here http://www.sensirion.com/en/sampling
http://www.sensirion.com/en/sensors/humidity/sensors_devices/sensorSHT11.htm
Kind Regards
Henrik Nielsen
IC Teknik

 

[Chris Fowler]

Hi
Look here http://www.sensirion.com/en/sampling

Looks great. I'll test it out.

http://www.sensirion.com/en/sensors/humidity/sensors_devices/sensorSHT11.htm

 

[Henrik Nielsen]

Hi
Look here some thing to test it with
http://peterpolm.tripod.com/sht11/index.html

Kind Regards
Henrik

 

[Rich Webb]

I'm looking for a schematic that will allow me to build
a humidity sensor and attach to me serial port. I'll then
write software under Linux to read the port and display
meaningful data. Any links?

Thermometrics makes some inexpensive resistive relative humidity sensors
that work OK in battery-powered apps. Recently had to replace one in an
outdoor wireless RH + temperature sending unit that had a bad experience
with Hurricane Isabel. Humidity sensors, as a rule, prefer not to spend
excessive amounts of time submerged in brackish water...

The Thermometrics HSP15P (Newark 39C2249) is reasonably affordable for
small qty purchases. Specs at
http://thermometrics.com/assets/images/hs1215p.pdf

Couple that with a few passives, a microcontroller with a built-in UART,
and a small power supply.