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Look at the sensor data sheets. Most have internal compensation circuits for temperature.Hello,
I am also working on a nitrox/trimix analyser.
At the moment I make my resarch and just collecting info about different solutions, investigate the codes, components and try to find my solution.
At the moment the selection of the O2 sensor cause me some headache.
There are different sensors available, some of them has 2 but others have 3 pins.
As I see for the diy projects everybody use only 2 pins out of 3 on the O2 sensor.
So I made some research to find the purpose of the 3rd electrode and found these articles:
Voltammetry - Wikipedia
Amperometric Sensor - an overview | ScienceDirect Topics
I also found an interesting datasheet here, but the electrical part is too complicated for me at the moment:
I also found a diy analyser setup where a resistor was connected between the sensor pins.
Some O2 sensor datasheets also recomment to use a 10k load resistor.
I do not see any external load resistors in the diy projects here.
Why nobody use it?
This is a quite good description how o2 cells work and the purpose of the external load resistor and some failure analytics.
Understanding Oxygen Sensors ADVANCED DIVER MAGAZINE byPaul Raymaekers
I think for more precise measurement a 3 electrode system is necessary. And it requires an additional electric circuit.
But I do not know if we really need it. I have not seen any projects where the 3rd pin with a compensation circuit was used.
Do we need it or we can skip it?
Once I'm confident that my code works in varying circumstances, I'll publish the code that is required for the main operation.Hello Miyaru,
I came across this thread looking for a DIY oxygen analyzer.
I have some friends with old/spare CCR oxygen cells and I was planning to give a try to the oxy analyzer.
Then I found your actual project and it looks awesome.
Putting together oxy/helium/CO cells is a must .
Really impressed of the results so far.
Do you plan to share your code in the future or is it a more "personal" project you want to keep ?
Keep up the good job !
Perfect - I've ordered my MD61 last week tooRight now I'm waiting for an MD61 to arrive (really curious about the difference with an MD62),