Temp/Humidity componants

[Bobw]

I want to build a Outdoor temperature, indoor Humidity sensor/display to control my humidifier.
Since what you set your humidifier to is based on out door temperature, the temp sensor will have to be external and remotely connected. I do plan on using a hard wire connection. Was thinking my old temperature probe from my weather station. I think it just uses a thermistor in it. Not sure what to use for the humidity sensor. there are many to choose from, some analog some digital. only needs to read 5% up to 60% max. Temperature from -20F - 100F it does get cold here in Michigan.
I was looking at microchip's web site, and could not find their PIC picker that they use to have. Still looking for that one.
I have a few 16F series chips here now, but most only have ADC inputs on them.
I will be using FC ver 5.5 to build this.
I am pretty sure I can handle the code part. Not to sure about PIC or Humidity sensor. Will be using a back lit 4x20 LCD. Got pretty good at coding those.

Will need:
Input for temp/Humidity sensor.
On/Off switch input.
+- Switch input (to over ride the setting by +- 5%)
I have the relay, voltage regulators, resistors and other hardware I would need.
Temp sensor???
Humidity Sensor???
PIC????
I have read most of the post on here but still not sure what to use.
Suggestions?

[Benj]

Hello,

We use the DHT11 module on one of our E-blocks and this has an inbuilt temperature and humidity sensor and is accessed via a I2C bus so you should be able to communicate with the sensor over a length of cable.

Here is a demo file that shows how to talk to the sensor.

eb079 03 - v5.fcf

(31.37 KiB) Downloaded 372 times

[Bobw]

Ben,
Thanks for they reply.
I had run across several post using that sensor.
For my application the temp sensor will be out doors, and the humidity sensor in doors.
I was looking at a resistance change type sensor http://www.elecrow.com/download/HR202%2 ... Sensor.pdf
So that I could just use one of the ADC channels on the PIC.
The temperature one is easy. I do NOT need a lot of accuracy here if both the temp and humidity were off 1 whole point no big problem. Humidity is being looked at in 5% increments, and temperature in 10 degree increments.
I want to control a whole house humidifier. If you are not careful balancing the indoor humidity against the outdoor temperature you end up with all sorts of condensation on your windows in the winter time. I have already partially written a FC5 that works. Many decisions icons used to check temperature, then compare that to current humidity.
Have also put in a +5% -5% switch too easily increase/decrease the value if need be.
Problem I am possibly seeing is that the humidity sensor runs from 1K up to 1Meg of resistance.
Still kicking it around.

Bob