Off Topic, Humidity Question

Slightly off topic, but... I have a 1 wire Temp / Humiditiy sensor mounted on the North Side of the house, under the roof, in a small plastic box with some holes drilled in for airflow. This is connected to a temp08 and into homeseer. The temperature readings seem pretty accurate, the humidity sensor seems a bit high. I use the local Airport readings as a comparison.

Now that Winter is upon us I've noticed that the Humiditiy readings I'm getting are pretty nearly flat line at 100% with maybe a slight drop mid afternoon. What I'm wonderting is wheter a) the location of the sensor is correct (I did some reading that suggested the north side in of the house was best) b) the housing that I have the sensor mounted in has sufficient airflow (is this important).

Thanks

Phill

[johnwpb]

Actually the airflow is the most important issue with a humidity sensor. A humidity sensor needs to be as "open air" as possible, and allowing for some protection of course. As the temperature is getting cooler, there is probably a lot of condensation building up in your enclosure. Think of a cool morning, and how wet things are in the mornings.

This condensation can build up in the box, and not toatlly evaporate during the day, before it starts all over again. And when it does begin to evaporate, thus the high readings.

The more open the enclosure that you use, the more accurate the readings are going to be.

Try moving the sensor closer to the house and higher, there it shouldnt need much more protection than the eve itself can provide. Just to test, take it out of the enclosure for a day and check your readings.

[Phill]

Thanks John for the quick reply.

According to my calculations its 4am in Florida, Can't you sleep ???

Phill

[Rupp]

clokep,
For better readings you need you humidity sensor in the open in a pagoda.

See these pictures of a home made pagoda. It's made from plastic bowls from WalMart. All the bowls except for the top and bottom bowl have a 2.5" hole in them for air flow. I have both my temp sensor and humidity sensor mounted here.

[Phill]

Rupp.

Most impresive.. I guess this is my project for the weekend..

Thanks.

Phill

[johnwpb]

Most Impressive Indeed! That is really nice work Rupp! Not only, very professional looking, it is an inexpensive sollution. I LOVE it when those 2 things come together

Clokep: I run an Internet hosting company, and do 90% of my work from home. I usually only sleep 4-5 hours a day.

[Rupp]

Thanks Guys,
One thing I did was to sand the bowls and paint them glossy white. This is very important to reflect all the heat. I then laid all the bowls on top of one another and drilled three evenly spaced holes through all bowls. I used threadall bolts to connected them together. I used plastic tubing cut in (If I remember correctly) 1.5 or 2 inch section to use as spacers between the bowls. I started stacking them and when I got to the middle I attached the humidity sensor and temp sensors using floral wire to secure them to the "middle" / "center" of the drilled hole. The bottom is connected with PVC to a chimney antenna pole. If you have any questions give me a yell.