Medical Forum - trying to read O2 sensor

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I'm trying to make a ventilator.  One of the main  functions is to measure oxygen level present in air flow through the ventilator pipe, for that I bought a medical Osensor.

Looks like this

 

The sensor has three pins. As per the datasheet the pins are mentioned as 1(+), 2(-), 3 (-).

 

I contacted the dealer and asked about interface of the sensor to controller, he didn't reply properly. Still I have this doubt how to interface with the controller. 

 

If anybody knows how to do it? please reply for this post.  Thank for reading

 

Last Edited: Fri. Jul 31, 2020 - 07:59 AM
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These things seem to be a generic part. From what I've Googled they are a fuel cell, so they give a voltage relative to the amount of oxygen. This voltage is in the range of millivolts, so reading it might be challenging.

As well, you might be dealing with explosive mixtures of gas, so the circuitry may need to be intrinsically safe and as a medical device, there will be functional safety requirements. Basically you need to determine if the sensor is working correctly and take steps if it isn't - you don't want to give the patient too much or too little oxygen as either could cause death or impairment.

 

EG:

https://www.nuova.de/en/medical-...

 

 

 

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Thank You for your reply.  I'll make sure whether the sensor is good to use for the ventilator.

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I don't think the sensor is the issue - your 'ventilator' is the point of concern.

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Points for trying to help, but I think at this time you're going to learn how little you actually know.

 

Many very smart guys have spent years building ventilators, and while they may have been marked-up and patent-encumbered, they are still not simple devices.

 

They have great ranges of how to go wrong.  Please - unless you have years of experience and significant medical education in this field - don't.

 

Thanks.  S.

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Scroungre wrote:
... marked-up and patent-encumbered, ...
The Renesas effort has an oxygen sensor; the Trinamic effort has pressure and volume sensors.

New Open-Source Ventilator Design Joins the War on COVID | Electronic Design

by Lee Goldberg

MAY 11, 2020

Renesas' reference design is another sign that the pandemic may be transforming the medical devices industry. The global crisis appears to be creating alliances between former competitors and leveraging the power of open-source design.

...

Open-Source Platform for Smart Ventilators/Respirators Joins the War on COVID | Electronic Design

by Lee Goldberg

JUL 24, 2020

In this review of Trinamic's open-source hardware/software platform for respirators and other medical equipment, you'll find out about the power system that drives it, what the platform is good for, and how it stacks up against the others.

...

[Figure]

3. TMC4671+TMC6100-REF-TOSV firmware control loops.

Having seen this in action (as opposed to .ppt slides), I'm hopeful that the company will be able to help developers implement the many subtle functions that respirators and ventilators must do to work in harmony with a patient's lungs, rather than slowly damaging them.

...

 

"Dare to be naïve." - Buckminster Fuller

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Not really on topic, but a little bit related:

 

GasLab.com has a short discussion on 9 different methods of measuring O2 concentration!

 

JC

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DocJC wrote:

Not really on topic, but a little bit related:

But another page on that website is exactly on topic:

https://gaslab.com/blogs/articles/oxygen-sensors-ventilators-coronavirus