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Humidity Sensor?

WayneW

Senior Member
I don't know of any easy way to use a humidity sensor, but would a humidistat work? That is like a thermostat, except you set the dial for the humidity level you want the contacts to close at. It just has a simple contact output, so you wire it to any zone and then write rules.
 

Steve

Senior Member
I don't know if its exactly what you want, but the George Risk H8800 lets you set a low limit and a high limit. When those limits are reached, they trip relays which could be hooked into Elk zones. So it doesn't give full Humidity info in the Elk, but at least thresholds. And they are not inexpensive, I think around $85
 

gcimmino

Active Member
Would something like this work?

It's $33 at Digikey and has a voltage output that varies with humidity from about 1.3v to 3.5v.

You'd set the Elk Zone to Analog (Type = 34). From what I've read elsewhere here, there's an 8 bit DAC over a 14v range. This should give you about 40 unique values over the 1.3v to 3.5v range of the sensor, good for at least 5% RH differences.

Just a SWAG, but might help.
 

BraveSirRobbin

Moderator
gcimmino said:
Would something like this work?

It's $33 at Digikey and has a voltage output that varies with humidity from about 1.3v to 3.5v.

You'd set the Elk Zone to Analog (Type = 34). From what I've read elsewhere here, there's an 8 bit DAC over a 14v range. This should give you about 40 unique values over the 1.3v to 3.5v range of the sensor, good for at least 5% RH differences.

Just a SWAG, but might help.

Good find gcimmino but FYI:

Beware using the Elk inputs as analog type. :) There is an internal pull-up resistor that the sensor will have to overcome (with drive levels). Also be aware that the zones on an expansion board will only update every 30 seconds (unless a zone on that board changes out of the "EOL" safe zone value range).

If it does work, you may want to browse my Analog to Digital Converters Guide.

If you are using HomeSeer there are a few methods of getting this data to a HomeSeer device (via Electron's or MarkL's plugins). Mark's has a feature that will let you convert to the humidity units directly and stuff that value into a HomeSeer device (by entering the "m" and "b" values from the slope intercept foruma in an ini file). You can get those values via the data sheet of the humidity sensor.
 

Guy Lavoie

Active Member
The only thing about using an Elk input for reading analog voltages is that there is no easy way to disable the built-in 2k pullup resistor to +14v. To do it, you need to physically remove a small soldered-in surface mount component (the resistor) which will then void your warranty.
 
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