DIY Wireless Temperature Sensors - recommendations?

[drmike]

Working on or wanting to work on some building projects over the winter.


One thing I am experimenting with is various materials for simple R-value - think insulating value or ability to keep heat in or out (both are of interest).


Looking for cheap and open source solutions for sensing temperature (thermometer) and transmitting those datapoints real time to a central collection station.


Looking for something ideally ready made on the sensor with simple controls in Linux / means to get the data from the device.  


Tethering to USB is fine, can use wifi to communicate on this.  


Looking for sensors that have about -30F to 400F range (that's outside temperature minimum and temperature near heat exchanger - not directly in flame path).


Anyone have currently or prior experimented with anything that sounds usable?  Arduino solutions may be fine, but I am just entirely unfamiliar with.

 

[JahAGR]

I use a "TEMPer" USB temperature sensor to monitor room temp. It looks like they've updated all the models since I got mine, as the new ones have all metal cases for the electronics and a detachable probe.


example http://www.pcsensor.com/usb-thermometer/temperntc.html - They make a few different models, some with external probes, some without, some that do humidity as well. They can be found cheaper than these list prices on ebay/dealextreme


I believe they show up as standard HID devices so tethering to a raspi or something should be pretty easy. I personally use some truly awful Windows software called ThermoHID


I also played around with the TMP35/36/37 devices with an Arduino and honestly the whole thing is a pain in the ass. No good way to mount it, your lead wires can affect temperature accuracy, possibility of measurement voltage drop from wiring or induced noise, have to roll your own software, etc... I'd recommend the premade USB solutions any day.

 

[drmike]

I use a "TEMPer" USB temperature sensor to monitor room temp. It looks like they've updated all the models since I got mine, as the new ones have all metal cases for the electronics and a detachable probe.


example http://www.pcsensor.com/usb-thermometer/temperntc.html - They make a few different models, some with external probes, some without, some that do humidity as well. They can be found cheaper than these list prices on ebay/dealextreme


I believe they show up as standard HID devices so tethering to a raspi or something should be pretty easy. I personally use some truly awful Windows software called ThermoHID


I also played around with the TMP35/36/37 devices with an Arduino and honestly the whole thing is a pain in the ass. No good way to mount it, your lead wires can affect temperature accuracy, possibility of measurement voltage drop from wiring or induced noise, have to roll your own software, etc... I'd recommend the premade USB solutions any day.

I've looked at that TEMPer USB stick too many times... Just never could determine if it would work with Linux and if anyone actually got it to work... Like most import stuff, the model gets rebadged and tossed about, so uncertain when buying if model will be what someone else has actually had success with.


Off to do more research on that model

 

[JahAGR]

http://dev-random.net/temperature-measuring-using-linux-and-raspberry-pi/ here's someone who did a full writeup from start to finish


He does mention that the temp was 6degC off which is surprising to me. The plug on the wired sensor one is a TRRS which would imply it's a 4-wire sensor and those are supposed to be pretty accurate. I am surprised they wouldn't calibrate out the error at the factory. I never checked the accuracy of mine but it's certainly not 6C off.


Here's another  http://www.linuxjournal.com/content/temper-pi


Regarding clones or fakes, I'd say as long as they specify it's a TEMPer device it'll be compatible with all the software. I'm pretty sure when I got mine I just searched on ebay and ordered the cheapest one.

 

[drmike]

http://dev-random.net/temperature-measuring-using-linux-and-raspberry-pi/ here's someone who did a full writeup from start to finish


He does mention that the temp was 6degC off which is surprising to me. The plug on the wired sensor one is a TRRS which would imply it's a 4-wire sensor and those are supposed to be pretty accurate. I am surprised they wouldn't calibrate out the error at the factory. I never checked the accuracy of mine but it's certainly not 6C off.


Here's another  http://www.linuxjournal.com/content/temper-pi


Regarding clones or fakes, I'd say as long as they specify it's a TEMPer device it'll be compatible with all the software. I'm pretty sure when I got mine I just searched on ebay and ordered the cheapest one.

Awesome find there, awesome.


Off to find a USB thermometer, already have idle Pi's sitting here (don't we all?).

 

[drmike]

Yeah these Temper USB models are a PITA to find.  


Ebay is sellers in China pretending to be in the US. 
Amazon is sellers in China saying shipping will take until well into December.


Off to search the alternative buying world of search results

 

[drmike]

So I picked up one of the TemperUSB thermometers.


Works well aside from the USB security crap Linux seems to always get in the way of everything and without easy enough documentation to resolve the issue.


Means basically running things as root.   Meh, I stay root, but yeah, crontab won't roll like that, so have to run task otherwise.


This page: http://dev-random.net/temperature-measuring-using-linux-and-raspberry-pi/  is pretty awesome for this device.  Problem is the software there has a bug / needs adjusted to deal with USB unavailable condition.  Specific problem to the software as no such issue with another Python script to interface with the Temper.  Same permission issue with the other Python code, but no unavailable condition.


So far not seeing any of the off temperature readings.  Have it running off an ARM box with 12V and 2A power supply... Probably the origin of most folks oddness....

 

[willie]

I've been thinking of getting a TI SensorTag but its IR sensor doesn't handle the extreme temperature range that you wanted (60 Celsius max, I think).  Feature list is here:


http://www.ti.com/ww/en/wireless_connectivity/sensortag2015/tearDown.html

 

[drmike]

So I picked up one of the TemperUSB thermometers.


...


So far not seeing any of the off temperature readings.  Have it running off an ARM box with 12V and 2A power supply... Probably the origin of most folks oddness....

Woke up this morning to my USB device offline.  Problem is the ARM computer it is attached to... Unsure if power savings or what.   Had to hard power reset the damn thing.  Unsure if dealing with software settings at play or if the Octa ARM technically is crashing - no terminal response and it isn't display tethered... Meh.


Back to the drawing board.


Next up is tethering this to my Raspberry Pi instead.. Since it is always on and no offline weirdness or power savings on the board itself as config'd.


Problem if anything, my guess, is that the Pi USB power / power supply for it might create a problem / end up with weird temperature deviation.  


This is how I am spending the start of my day..  Time of year where I need sensors in place and to get some more monitoring and dev done around it. Trying to move towards alerts that are automated, so I can ignore HVAC stuff and get notified just when I have need to get up to adjust things, instead of visual and human perception randomness which is lousy at best or ends up chewing too much of waking hours.  Intent here is to use technology to deal with aspiring off grid / traditional heating in harsh environments - extreme weather that swings randomly, misfiring that happens due to inconsistent burns, differences in fuel, etc.  Issues with burn stages, cleanliness or lack of burners, differences in fuel storage (i.e. stored indoors and has been vs. recent new fuel that may or may not have differing water content).  Bunches o' variables.   Good use of technology at least to perfect things and give proactive notices.

 

[drmike]

I've been thinking of getting a TI SensorTag but its IR sensor doesn't handle the extreme temperature range that you wanted (60 Celsius max, I think).  Feature list is here:


http://www.ti.com/ww/en/wireless_connectivity/sensortag2015/tearDown.html

These are mega neat and new to me.  Any idea of the price point on the Ti SensorTags?

 

[gxbfxvar]

These are mega neat and new to me.  Any idea of the price point on the Ti SensorTags?

SensorTag2 is about 30 euros at Mouser:


http://www.mouser.fi/ProductDetail/Texas-Instruments/CC2650STK/?qs=sGAEpiMZZMvzv9EAOJZmO9jCa%2f7ZiU4XhAFqCiEJ5X8%3d


or $29 directly from TI: https://store.ti.com/cc2650stk.aspx


To control these from Linux, you need to have Bluetooth Low Energy stuff on the system (BLE USB module and kernel/user space drivers; modern distributions should have them by default). Some example code can be found from https://github.com/sandeepmistry/node-sensortag