I am hoping someone can recommend the right sensors and wire for this project. I'm still a noob but not afraid to get stuck in! The project is to put some sensors for temp and humidity into my two foot think stone walls of the house to measure the improvement after I add external insulation. Which are the best sensors to go for? They don't have to be very accurate but will need to be there for a few years in damp conditions. Also, more urgently, what kind of wire should I run given that they will have to travel up to 100' to get back into the house and to the computer. I'm looking to put about 20 sensors in in total.
Any suggestions welcome.
Phoebe.
Measure temp/humid in old stone walls
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adafruit_support_bill
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Re: Measure temp/humid in old stone walls
I'd suggest the DHT-22, or the wired version of it, the AM2302 - http://www.adafruit.com/products/393
Although the 100' cable requirement will likely be an issue. You will probably need to put a microcontroller closer to the sensors and have it re-transmit the data up to your computer.
Another thing to look out for: Humidity sensors are fussy things. If the sensor gets wet or contaminated with dust/dirt, it will affect the readings. If you are stuffing these into a stone wall, you might want to wrap them with some filter material first to keep the dirt out. If they do get wet from condensation, they usually recover after some time if they have a chance to dry out.
We do have these that are designed to be buried: http://www.adafruit.com/products/1298
But that would be pretty expensive of you need 20 of them.
Although the 100' cable requirement will likely be an issue. You will probably need to put a microcontroller closer to the sensors and have it re-transmit the data up to your computer.
Another thing to look out for: Humidity sensors are fussy things. If the sensor gets wet or contaminated with dust/dirt, it will affect the readings. If you are stuffing these into a stone wall, you might want to wrap them with some filter material first to keep the dirt out. If they do get wet from condensation, they usually recover after some time if they have a chance to dry out.
We do have these that are designed to be buried: http://www.adafruit.com/products/1298
But that would be pretty expensive of you need 20 of them.
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brainfart
- Posts: 11
- Joined: Mon Aug 26, 2013 3:21 pm
Re: Measure temp/humid in old stone walls
I'd rather drive two nails or better yet stainless steel pins into the wall and measure the resistance between them, or rather the change in resistance as the walls dry out. This is the principle used in wood moisture meters, and some of them can also be used to estimate moisture content in other building materials.
If you want to use the higher priced moisture sensors, drill a bunch of deep holes into the wall. The sensor is put in that hole, allowed to equilibrate for an hour and then the measurement is taken. Plug the holes when not in use.
If you want to use the higher priced moisture sensors, drill a bunch of deep holes into the wall. The sensor is put in that hole, allowed to equilibrate for an hour and then the measurement is taken. Plug the holes when not in use.
Please be positive and constructive with your questions and comments.