I'm not sure which brand (AOSI sounds familiar but I'm not 100%), I just got the sample from my customer and instructions to "make it work." That it does! You can see it at http://www.rcboats.com A resistor, especially a 1%, doesn't change much across most temperatures. If you get the R and C balanced correctly, the tempco's will automatically offset one another. Andy TOM THERON on 04/18/2000 03:08:19 AM Please respond to pic microcontroller discussion list To: PICLIST@MITVMA.MIT.EDU cc: (bcc: Andrew Kunz/TDI_NOTES) Subject: Re: [OT] Humidity Sensor Interfacing I've used the second method to measure tilt with a capacitive tilt meter and it worked nicely. Can't say how it would do with the humidity sensor, but the technique works fine. I take 128 samples and throw away the lowest few bits. Andy I am also working on a capactive tilt meter, with the same idea as yours - don't know what sensors you use - AOSI? Anyway, I think you get better temp stabilization with the bridge, since with the 555/RC method the R component is influenced by temperature. However, in my application the device will be used in a temperature stabilized room, that way it won't matter that much. Tom