[GSBN] data loggers

Tue Dec 9 03:53:05 UTC 2014

Hi all,

Enga I remember we corresponded a bit on this - can't remember what I 
said, hope it was of some use! Been having quite a lot of trouble 
staying on top of my emails these days...

There are quite a lot of different sensors out there - more 
manufacturers than I can recall - and if you are looking for budget, you 
can find them pretty cheap if you can build/assemble the system 
yourself. I think GE and other companies sell temp and RH sensors for 
less than US$20/each, or even cheaper. Off-the-shelf, pre-assembled, 
ready-to-go packages will be more expensive, for sure - and I'm not 
terribly well-versed on those, as I've been working on making my own 
version rather than using other company's versions.

Some considerations for any sensor system (though some of these are more 
relevant to DIY than off-the-shelf):

- do you want to do a combined temp/RH sensor, or individual temp and RH 
sensors? What are you monitoring and where, how many do you need?
- what is the data range you need? this is a big one - if you need to 
get from really cold ambient temps to really hot, sensors go up in cost 
(same w RH, it gets more expensive to find sensors that give accurate 
readings at higher RH). If you go off-the-shelf, you need to look at the 
spec's and ensure the sensors will read within the environmental 
parameters you are seeking to evaluate. Otherwise, your data will not be 
fully representative of the conditions you are analyzing. Accuracy is 
another important feature (that also affects cost), as many sensors drop 
off in accuracy as you get to the far ends of their range. If you are 
doing research-quality testing, accuracy becomes all the more important 
than just for curiosity's sake or QC. This is a pretty crucial piece.
- how are the sensors wired, and what are they wired to? what are you 
thinking of using to receive the data? to analyze it?
- how do you plan on powering the sensors? hard-wire, or battery 
(wireless)? life-expectancy? how long to you plan on collecting data?
- how are you mounting/installing the sensors in such a way that they 
are protected from damage, yet still connected to the regional atmosphere?
- will the specific mounting and wiring regime allow environmental 
changes that will alter your data? i.e. conduits that could trap 
condensation, or wire that could conduct thermal energy
- how will you know which sensors are providing what data, and where 
they are located in the building? How do those locations relate to 
differing environmental conditions (i.e. solar orientation, vertical 
location)
- do you plan on retrieving the sensors for 
replacement/maintenance/repair/calibration?
- how will you calibrate the sensors for accuracy prior to installation?
- do you plan on also recording interior and exterior temp/RH to give 
full environmental context?
- will the building occupants allow needed resources for long-term 
testing (access, power, internet connection, etc)

I hope this isn't too overwhelming. These are some of the many questions 
I asked (really, am still asking) in developing our sensor system, given 
the goals of our project. But ultimately, it is the goals and intended 
purposes that will drive how you design your program. Like building, the 
devil is in the details, and a clear understanding of goals will lay out 
the design, which will inform those details. So like any good design, 
start with getting a clear sense of what you are looking to achieve, the 
logistics, budget, and time frame influencing the project, and see what 
solutions fit those parameters.

Hopefully most of these questions will be easy to answer, or not 
necessary to ask. I strongly recommend finding published studies of 
projects that have had sensors installed, whether bale or otherwise, and 
read the sections where they discuss methodology and the construction of 
the testing environment. They will give many good clues and precedent of 
how to set up a rigorous sensing system. That's a great place to start. 
They will also tell you the equipment they use.

I realize this may be more complicated of an answer than you might like, 
but if I remember correctly you are looking for research-quality data 
(forgive me if I'm wrong here), and so the rigor is all the more 
important in setting up a quality testing environment.

By the way, Frank gives me more credit than I deserve in describing our 
units as "already manufactured" - we've gone through a few iterations of 
development, and we are now stalled out pending my gaining enough 
control back over my schedule to push the project the rest of the way 
forward. I am expecting to inject more time into this later this winter 
for a more formal launch in the season ahead - though I've said that 
before...

Hope that's helpful, best of luck.
Jacob

On 12/8/14, 9:03 AM, Frank Tettemer wrote:
> Hi Enga,
>
> Jacob Deva Racusin, from Vermont, USA, is the person to talk with, 
> currently. He has the sensor units already manufactured, ready to 
> insert into the area of concern.
> I'm sure he can offer more detail.
> Jacob Deva Racusin <buildnatural at googlemail.com>
>
> Cheers,
>
> Frank Tettemer
> Living Sol ~ Building and Design
> www.livingsol.com
> 613 756 3884
>
> On 08/12/2014 7:49 AM, Enga Lokey wrote:
>> Hello All,
>>
>> Wanted to check in with any of you that have experience with data 
>> loggers in ongoing monitoring of temperature and humidity. Ideally, I 
>> will be imbedding dataloggers/sensors in the walls of a strawbale 
>> structure as it is built and then be able to monitor temperature and 
>> moisture movement within the wall from the plastering process through 
>> several years of use. If anyone is familiar with specific brands or 
>> types of equipment that either works particularly well or should be 
>> avoided, I would appreciate hearing about it. Economy will 
>> unfortunately be a factor as funding for these monitors seems to be 
>> getting more limited each day.
>>
>> Thanks for any and all input.
>> Enga
>>
>>
>> enga at thelokeys.net
>>
>>
>>
>>
>> _______________________________________________
>> GSBN mailing list
>> GSBN at sustainablesources.com
>> http://sustainablesources.com/mailman/listinfo.cgi/GSBN
>>
>

-- 
Jacob Deva Racusin
Co-Owner
New Frameworks Natural Design/Build

Author, The Natural Building Companion
Chelsea Green Press, 2012

(802) 782-7783
jacob at newframeworks.com
http://www.newframeworks.com