Getting Heart rate through iOS

You would need to write a pretty fancy filter to pull heart beats out of the accelerometer, but it could probably be done. It's a pretty sensitive device.

I don't think you could do it with the video camera and led light on though - but I have seen medical instruments that do this.

You might be better off developing add on hardware and using a finger sensor.

 

There are already several HR monitors available on iOS. I've never used them, but the best reviewed ones typically use the camera to view the change in color in your finger tip. They seem to work better on iOS devices that have the LED flash.

If you want to know the science behind it, do some research on pulse oximeters. These are the devices that they use in hospitals to get a continuous readout on your heartrate.

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Here's a link to an Android app that measures HR using the accelerometer. Can't vouch for the accuracy.

http://www.magic-heart-rate.com/

There may be some iOS apps that do it this way too.

 

This has nothing to do with the OS. You would start by carefully studying the sensitivity and range of all the possible physical sensors (both internal sensors and external accessories), and any digital signal processing, AI pattern matching and statistical analysis needed to process the results.

 

Then there's always the option of just telling the user to hit a button to start a timer and start counting the beats right then, and then telling them to enter how many they counted at the end. Provide instructions for how best to count.

If you insist on using hardware, I feel like if you press your finger against the camera with the flash turned on, your finger will pulse how red it is with each heartbeat. So if you just access the average color from the camera, that might work.

 

Maybe after you do some image processing, signal processing, autocorrelation and other data reduction (etc.) and analysis to determine if there are any measurable changes that have statistically valid and bounded periodicity estimate in the expected range.

Non-trivial.

 

That's really amazing that they can use the camera to detect subtle color changes like that. I had no clue the camera was that powerful.