Temperature Measurement for Lab and Science Projects

RE: Temperature Measurement for Lab and Science Projects

shabaz — Fri, 12 Jul 2019 02:36:59 GMT

The new version is almost complete.. It still needs to be tested (and code still needs to be developed too, it will be based on the existing code, but tested with Pi 3 and Pi 4).

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With this new version, there are two thermocouple connectors built-in. The board no longer plugs directly on the Pi, but is attached using a few jumper wires. The display is not part of the board, the display is a separate project (or use a 16x2 display etc.).

The other advantage of this new version is that it can be used with the VIKI project too, by removing the jumpers and replacing with a flat flex cable. With the VIKI project there is the extra advantage that the thermocouples are isolated from the Pi, and there is a built-in display there (16x2 characters).

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Once it is confirmed it all works (might be a few weeks, I need to write the code), I'll publish the details.

RE: Temperature Measurement for Lab and Science Projects

at0 — Tue, 09 Jul 2019 08:40:14 GMT

Hi all,

I have tried this project on a RPI 3 B and everything works perfectly fine, except of the LED output. Has anyone managed to succesfully adapt the code so that it also works on newer RPI models?

Thanks a lot!

RE: Temperature Measurement for Lab and Science Projects

lornamca — Wed, 27 Jun 2018 08:35:49 GMT

Hi Shabaz,

I am very new to building sensors and i was wondering if this design could be adapted to take 2 thermocouples instead of one?

I am thinking to build a system where you are monitoring a surface temperature and an atmospheric temperature at the same time. Is this possible with this setup?

Apologies if this is a simple question!

Thanks for your help,

Lorna

RE: Temperature Measurement for Lab and Science Projects

vr1080 — Thu, 11 Jan 2018 23:01:45 GMT

Glass Case:

https://www.amazon.com/gp/product/B00PH6RF0K/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

PCB File:

https://github.com/vr1080/Raspberry_Thermocouple_Project

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RE: Temperature Measurement for Lab and Science Projects

shabaz — Thu, 11 Jan 2018 22:52:16 GMT

Hi Vema,

Thanks for this!!

RE: Temperature Measurement for Lab and Science Projects

rhino1987 — Thu, 08 Jun 2017 19:47:31 GMT

I have a few extra PCBs should anyone be looking for one. Asking $8 US or $9 worldwide, including shipping which covers my costs of having them produced.

RE: Temperature Measurement for Lab and Science Projects

rhino1987 — Sat, 03 Jun 2017 21:30:43 GMT

Can anyone recommend a case/enclosure which fits the whole project?

RE: Temperature Measurement for Lab and Science Projects

shukla — Sun, 07 May 2017 14:46:42 GMT

Hi frd

I am used fist time R3 .So how i am setup window 10 pc as a R3 desktop. Setep by setep.

If you have a anay kind of links or video plss send no.

Thanx

RE: Temperature Measurement for Lab and Science Projects

ekwan — Sat, 22 Apr 2017 02:29:04 GMT

Aha! I see here the melting point of dry ice is actually -78.5 C, in which case, the measurement is actually just fine.

RE: Temperature Measurement for Lab and Science Projects

ekwan — Sat, 22 Apr 2017 02:06:27 GMT

Update:

New code has been pushed to the "eugene" branch. I need to document everything and then I will merge (or submit a pull request if you would prefer). I will also improve the documentation.

I calibrated the Pi thermocouple against another thermocouple from about 30 C to 90 C and the agreement is very good and linear. However, there is some discrepancy at -78 C (i.e., dry ice/acetone), so I need to double check my math. Overall, I'd rate the accuracy at about half a degree. Here are the raw data (expected, observed temp. in C):

-78.2-79.00.00.426.726.729.429.537.837.543.343.048.948.860.059.871.170.976.776.482.281.887.887.8

I wrote a very primitive flask application to display the data. I could never get the node application to work. I'm sure it's just some minor configuration bug. The flask application needs a .wsgi file to talk to apache2. I have included both the wsgi and a configuration file.

I am having a problem where the temperature is intermittently thousands of degrees. I wonder if I have a loose connection or some kind of noise in the system. Have you run into this before? I am using an ungrounded thermocouple where the junction is shielded in a stainless steel sheath. I figure that must reduce the noise.

RE: Temperature Measurement for Lab and Science Projects

ekwan — Mon, 17 Apr 2017 18:00:25 GMT

Hi Everyone,

I have mostly managed to reproduce this project on a RPi Zero with Wireless. I printed a PCB using 4pcb.com based on the files here. It was a bit expensive (about $50 including shipping), but the price might come down with additional boards (I only ordered 1 board). The only additional step is the requirement to solder on additional headers onto the Pi Zero. The other instructions work pretty much as written.

I want to use this device to monitor the internal temperature of chemical reactions, so I used a different thermocouple probe from Omega: KMQSS-062U-12. This is a 12 inch probe that does not have an exposed junction (suitable for immersing into a flask).

As discussed by previous posters, the adc_code2temp(int code) method in therm.c has some minor mistakes. (The notation on the Omega type K datasheet is very confusing in that the negative and positive temperatures are indexed differently.) I have constructed an awk script that reads the table and generates the necessary C code. It is a bit clunky, but I didn't want to bother with having C read the data file directly. There are slight differences between the existing code and the new code, so I would appreciate it if someone double checked.

Shabaz, can I submit a pull request with the corrected code? It will cover from -250 C to + 500 C in 10 C increments, which seems enough for most purposes.

I am having trouble getting the node.js to work. It just says "error loading index.html". I can come up with a different web solution, though.

Thanks very much to Shabaz for putting this great set of instructions together.

-Eugene Kwan

RE: Temperature Measurement for Lab and Science Projects

oidium45 — Fri, 03 Feb 2017 15:13:58 GMT

This probably goes without saying but EXCELLENT Job! I was looking around for several days trying to decide which direction I wanted to go with trying to read a thermocouple with my raspberry pi and this one seemed to fit the bill.

I am having one issue though.. I am using a raspberry pi 3 and am having trouble getting it to compile the therm.c file. using "gcc -o therm therm.c -lrt". I keep getting errors such as "error: stray '/' in program" and "error: expected identifier or '(' before '<' token" or "invalid suffix". Unfortunately there seem to be a few pages of such errors. I am relatively new to the Pi and was wondering if you had any suggestions.

Also, I noticed while reading comments that some people were having issues running on a raspberry pi2 and since I am running a pi3 no doubt I will run into issues with the software you wrote. Is it likely to simply be a matter of making sure the I/O ports/pins are specified correctly?

Thanks in advance! And thank you for posting this thread! It has been very helpful.

RE: Temperature Measurement for Lab and Science Projects

williaty — Fri, 04 Nov 2016 22:21:56 GMT

Is there any way to stack 4 sensor boards onto a RPi B+? I need 4 channels of acquisition and logging and it seems silly to buy and power 4 separate Pis to do this.

RE: Temperature Measurement for Lab and Science Projects

mconners — Fri, 19 Aug 2016 18:36:47 GMT

Hey Shabaz,

Great job as always. I've been playing with K-type thermocouples recently. I bought the max31855 chips and soldered them on to little DIP breakout boards. Curious though, do you feel the TI part is superior?

I plan to make a Web based PID controller out of an ESP8266 for a BBQ smoker so in the midst of my research, I stumbled onto this write up. Can't believe I missed it the first time.

Mike

RE: Temperature Measurement for Lab and Science Projects

Former Member — Tue, 26 Apr 2016 15:16:36 GMT

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Here is a picture of the modify case and modified PCB adapter. Let me know if you want more pictures and files for the PCB adapter