Heart rate monitor in a single package

[TommyGunn]

So I was looking at  this teardown https://www.ifixit.com/Teardown/Samsung+Gear+2+Teardown/23990

Turns out I have one of the chips they could not identify.



Anyone got a datasheet on this guy? I'm interested now.

[DJ]

Link did not work for me.

Maybe something using this topology as the front end?

http://www.analog.com/en/specialty-amplifiers/instrumentation-amplifiers/ad8232/products/product.html

[Andlier]

Link did not work for me.

Maybe something using this topology as the front end?

http://www.analog.com/en/specialty-amplifiers/instrumentation-amplifiers/ad8232/products/product.html

Except that the sensor is based on optical principles, not ECG. Maybe one of the Si114x IR/visible sensors coupled with some clever software could do the job... http://www.silabs.com/products/sensors/infraredsensors/Pages/default.aspx

[DJ]

Sorry,  did not click through the links.

If optical, likely similar to the pulse measurement of the galaxy s5.  This appears to use the pulse section of a standard pulse oximeter, but is reflective rather than transmissive (less accurate generally, and losing the oximetry capability)

[babysitter]

Reflexive doesn't necessarily mean losing the oxygenation information, but often the devices don't care for it - might be harder than with transmissive.

You get a photoplethysmography signal in any (healthy) case when you shine any reddish light on skin and pick up what comes back or goes thru.

The bobbling up and down of your photodiode current due to blood pressure in the watched tissue, with a low-frequency change overlaid given by breathing, and if you are unlucky lots of movement artifacts if your person under test is moving... or is a hyper-neurotic cat  O0 That is your raw pulse signal, just compare to a treshold,

Using at least 2 or depending on manufacturer up to 7 wavelengths, using the "color change" of hemoglobin depending on its oxygen saturation, is what gives you the SpO2 reading. (EMS Oxymetersm also the % of Hemoglobin spoiled by toxic gases)

[miguelvp]

The link had an extra dot. This one will work:

https://www.ifixit.com/Teardown/Samsung+Gear+2+Teardown/23990