Mounting Temp Sensors

hucker

Active Member
I would like to have temperature sensors in various rooms in our house, bedrooms + living spaces. I have easy access to most of the spaces so wiring is not an issue. I have two big questions:

1) Where in the room should they be placed?
2) How do I make them as unobtrusive as possible?

For the 'where', I worry about sunlight hitting them, locating them in the ceiling (read too high, away from register airflow...) These things will cause erroneous readings. Do I just need to calibrate after the install (e.g. each sensor has an offset). For my outdoor sensor can I just put it under the north eaves of the house in a location that is not heated (e.g. off our garage).

For the 'hide' part I'd really like them to be hidden completely, there are smoke detectors, sprinklers, light switches, speakers, lights, alarm keypads. I fear it is going to look terrible (wall acne). Is there a nice way hide this stuff? I'd really like to NOT have a Decora plate for each of my 1wire sensors...

Chuck
 
I crimp my room temp sensors onto a RJ11 plug and plug it into the same jack where the telco plug is made. All that can be seen is the black head of the TO92 package.

I also have LAN and Video at the same junction so it is a 6 pack modular plate. My plates are mounted 14" from the floor so my readings are slightly on the low side compared to eye level, but no matter where you put them you will need to calibrate for their intended purpose. Anything mounted on the wall will tend to be biased by the wall temperture which will be cooler in the winter for outside walls vs the walls that do not have exterior exposure.

The other technique that I have seen others use is to mount them inside one of the room freshener dispensers thar are wall mounted. This hides them and still provides the slots for airflow.
 
Michael McSharry said:
I crimp my room temp sensors onto a RJ11 plug and plug it into the same jack where the telco plug is made. All that can be seen is the black head of the TO92 package.

I also have LAN and Video at the same junction so it is a 6 pack modular plate. My plates are mounted 14" from the floor so my readings are slightly on the low side compared to eye level, but no matter where you put them you will need to calibrate for their intended purpose. Anything mounted on the wall will tend to be biased by the wall temperture which will be cooler in the winter for outside walls vs the walls that do not have exterior exposure.

The other technique that I have seen others use is to mount them inside one of the room freshener dispensers thar are wall mounted. This hides them and still provides the slots for airflow.
Hi Michael,

Nice solution incorporating the sensor in an RJ-45, be interested in finding out what you connect them back to? What is the TO92 package? 1 Wire?

Regards,

Fleetz
 
I must admit I did the same, crimping into the RJ45 works great, the offset for mine is about a degree, mine are crimp in this way My Webpage

So that they are easily compatable with all my stuff and hobby boards stuff.
 
Michael McSharry said:
I crimp my room temp sensors onto a RJ11 plug and plug it into the same jack where the telco plug is made. All that can be seen is the black head of the TO92 package.
This sounds really cool, though I think a picture would be worth a 1000 words here. If I understand you correctly you wire your 1wire stuff up to an RJ11 plug and then have a little stubby connector that plugs in with the sensor. How far does this stick out? 1/2inch?

For me this would make more sense using RJ45's to tie into my hobbyboards stuff but I like the idea. CT rules!
 
A little blurry, but you get the idea. In this case it is in a 4 port wall plate in the lower right. You can see that it is smaller than the RF connector in the same plate. On the backside are modular connectors that have the airtight press-on cat5 connection to the RJ11 plug.

I elected to use RJ11 vs RJ45 because I already had all my rooms wired with the center conductors going to telco. I used the two outside pins (1 & 6) which also made the crimp much easier since I just needed to separate the sensor legs so there was slight tension to hold them to the outside of the RJ11 when I crimped.

I would show more detail of the sensor itself, but my camera does not do macro. What I did was inserted a very small piece of heat shrink and bent one outside leg over and soldered it to the other outside leg. Then I too the unbent leg and the center leg, cut them so the sensor head would be partially inside the RJ11 plug.
 

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I'll have to think about this a bit more. I have 1,3,5 year olds and wonder if that little black thing will be too much for them to resist yanking.

I might see if I can make something a bit stronger than the sensor package. Thanks for the great idea.

Chuck
 
Is is better to put it higher and out of harms way. The design parameters should consider some form of insulation/separationn from the wall so you can sense air rather than wall temperature. The desired way to connect different sensor is daisy chain the cat5 with the sensor mounted as close as possible to this wire. Pigtails introduce reflections which can cause problems. In my case with the telco wiring I have a home run wiring schema and use a 1-wire hub at the home-run center and then from the hub to the computer.
 
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