Years ago I used a 1N4148 for temperature sensing and made a humidity senso=
r using inter-digiting fingers on a PCB.=20

If this is a one off project, that could work for you. The diode I think is=
 done my measuring voltage across it for a constant current, but the spec s=
heet would help here, and the PCB humidity sensor is a resistance measureme=
nt, which will need calibrating. Both comply linear voltage measurement.

On 2011-06-25, at 1:44 PM, V G wrote:

> Hi all,
>=20
> I'm looking for a relatively cheap (~$10 for humidity sensor, ~$5 or less
> for temperature sensor) for my project.
>=20
> Right now, I'm looking at the following:
>=20
> Temperature: DS18B20 (
> http://ca.mouser.com/ProductDetail/Maxim-Integrated-Products/DS18B20+/?qs=
=3DsGAEpiMZZMvbyeSUH4qH%2fLbikZ7SIep9
> )
>=20
> Humidity: HIH-5031-001 (
> http://ca.mouser.com/ProductDetail/Honeywell-Microswitch/HIH-5031-001/?qs=
=3DsGAEpiMZZMseu6oguAZpqee7rmuRi3v3z4pHD5zNNiU%3d
> )
>=20
> Requirements:
> - Low voltage (3.3V compatible).
> - Easy to interface (digital bus outputs are nice, such as SPI, I2C, 1wir=
e,
> etc), I don't want to be measuring capacitance or frequency. I can work w=
ith
> linear voltage measurement.
> - Humidity range: 0-100% RH.
> - Temperature range: nothing special, anything standard will most likely =
do.
> - Cost: as mentioned above. I don't want to be spending $40 for a chip.
>=20
> Can anyone recommend better? Have any experience with a particular produc=
t?
> --=20
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist


--=20
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