Connecting an additional TypeK thermalcouple

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|  
Report Content as Inappropriate

Connecting an additional TypeK thermalcouple

Waggotamp
Hi Alfred

I have had a request to connect a type K thermal couple to the Liv Pi - Can you let me know how I would go about this?

Thank you

Tony
Reply | Threaded
Open this post in threaded view
|  
Report Content as Inappropriate

Re: Connecting an additional TypeK thermalcouple

AlfredC
Administrator
Hi Tony,

I think there are a couple of options:

1) Use a USB adapter like this one:
https://www.amazon.com/Thermocouple-Measurement-Device-Windows®-Linux®/dp/B003DV02B0

You can connect it to LiV Pi via USB and write a piece of Python code similar to:
https://github.com/FirstCypress/LiV/blob/S_development/software/liv/livDB/co2Sensor.py

You need to know the protocol (serial connection settings, message format) of your adapter. Not sure if the manufacturer documented message format for this adapter. I suppose you could use a sniffer (e.g. wireshark) to find out the format of messages yourself. Your code would be very similar to the co2 sensor code, connections settings and the message exchanges would be different.

I  also searched for open source thermocouple USB adapters and I found this one:
http://www.yoctopuce.com/EN/products/usb-environmental-sensors/yocto-thermocouple

(it has a Python library btw. at section 14:
http://www.yoctopuce.com/EN/products/yocto-thermocouple/doc/THRMCPL1.usermanual.html
 - you need to take some time to read through their rather large user manual to see how to configure and use the device. Looks like a mature product to me.
 
2) Connect your thermocouple to LiV Pi via I2C (there is an I2C port available on LiV’s back). You can use a TMP513 chipset, have a look at the schematics here:
http://www.clever4hire.com/special-articles/home/a-thermocouple-measurement-circuit
If you use this chipset (or a similar one), you need to see the message format over I2C bus so you can write your code. Your code would be somewhat similar to LiV LCD code. You should also make sure that there is no I2C address conflict with BMP180, LCD and DS3231 (for TMP513, address is B8 so that should be OK).
If I find an open source project or code sample, I will add the link here.


Once you get the measurements on LiV, you can write them into LiV DB, add a new graph, trigger alarms, etc...

Best,
Alfred


Loading...