I am looking to find out what sensors can i use in my wearable, to detect if someone is breathing.. we would also like to find out their breathing pattern if it is long deep breath or shallow breath.
\$\begingroup\$
\$\endgroup\$
5
-
2\$\begingroup\$ Old school stethoscope? \$\endgroup\$– dext0rbCommented Apr 18, 2014 at 17:31
-
\$\begingroup\$ but am looking to develop it as a wearable.. \$\endgroup\$– user40538Commented Apr 18, 2014 at 17:33
-
2\$\begingroup\$ probably some sort of elastic strap (worn around the entire body at chest level) with a strain gauge \$\endgroup\$– tcrosleyCommented Apr 18, 2014 at 17:37
-
\$\begingroup\$ Is this for some one off academic project? \$\endgroup\$– Matt YoungCommented Apr 18, 2014 at 17:51
-
1\$\begingroup\$ Need more parameters. What is your "wearable"? How does it interface to the world? Does it have an ADC? Digital only? Do you want an off the shelf sensor or are you able to develop the sensor yourself? \$\endgroup\$– dext0rbCommented Apr 18, 2014 at 17:56
Add a comment
|
3 Answers
\$\begingroup\$
\$\endgroup\$
2
There are two main methods you can use -- impedance plethysmography (http://www.bem.fi/book/25/25.htm) or a simple belt transducer (http://www.thoughttechnology.com/sciencedivision/pages/products/respiration.html) -- but search on "respiration belt sensor" for a variety of methods to do this. Some use strain gages, some use pressure in something like a cuff. The first time I've ever seen this described was simply a rubber tube filled with mercury, but you don't want to do that!!
answered Apr 18, 2014 at 19:59
-
1\$\begingroup\$ Pneumatic is the way to go. There's a reason that the MRI manufacturers use that technology for cardiac gating. Other than having a small MRI signature, it's more robust, and just works. \$\endgroup\$ Commented Apr 19, 2014 at 2:38
-
\$\begingroup\$ +1 for your link to the belt transducer -- I looked all over for one when I added my comment about an elastic strap to the OP's post, but couldn't actually find one. Must have been using the wrong keywords. That is exactly what I had in mind. \$\endgroup\$– tcrosleyCommented Apr 19, 2014 at 17:25
\$\begingroup\$
\$\endgroup\$
5
Breath rate can be extracted from heart rate from ECG signal, so wearable ECG sensor may be used.
Heart speeds up during inhale and slows down during exhale.
To get more information - you can search the web for "respiratory sinus arrhythmia biofeedback".
-
\$\begingroup\$ thanks for your reply... this is great info.. i was wondering that there will be challenges to package this into a customer centric wearable device.. and the form factor is another issue.. is there any accurate motion sensor that can be used? \$\endgroup\$ Commented Apr 18, 2014 at 19:34
-
1\$\begingroup\$ Actually, this isn't robust enough to use reliably. There are methods to pull respiration out of ECG devices, but they generally use impedance plethysmography techniques using ECG electrodes that already are on your chest because you're having an ECG. \$\endgroup\$ Commented Apr 18, 2014 at 19:53
-
\$\begingroup\$ @ScottSeidman I thought that method with RSA is used in some commercial equipment (for sport?).. \$\endgroup\$– KamilCommented Apr 20, 2014 at 16:26
-
\$\begingroup\$ @Kamil None that I know of, or that I would buy. If there's already electrodes on a person, there are better alternatives immediately available \$\endgroup\$ Commented Apr 20, 2014 at 16:47
-
\$\begingroup\$ For example, the TI analog front end for ECG, ti.com/lit/ds/symlink/ads1298.pdf has respiration measurement circuitry right on board, and it has nothing to do with heart rate, but rather an oscillator used to generate a signal for impedance plethysmography. \$\endgroup\$ Commented Apr 22, 2014 at 0:02
\$\begingroup\$
\$\endgroup\$
Borrowing @tcrosley's comment (+1) suggesting measurement of thoracic expansion, here is a thesis in which the candidate came up with a home-made optical strain sensor for just this purpose.
This was the voltage output:
I would think a small load cell, an LVDT, or a capacitive sensor would be better, but he got this one to work well enough to finish his thesis.
answered Apr 18, 2014 at 19:43