Looks like an interesting application, BUT: it wants full network access. Why does this application need network access? We really need to start asking questions like that...
I've not used this app but this is definitely possible and has been covered in the literature. The final link is to a paper presented recently which actually proposes using a mobile phone for this.
Would be interesting to see what other information can be extracted from optical signals. Tricorders can't be that far off now.
This is a neat idea and one I was both surprised and excited to find in the app store when I was looking for such a thing. Sadly it fails in implementation, it just doesn't work terribly well, I almost wonder if they are just faking it and have some heavy bias to report 80 bpm, since that's believe for most.
But in my experience at least, when you compare it to a real heart rate monitor, it is always quite off.
It would be cool if someone with a real heart rate meter could run some tests to see how accurate this is. For what it's worth, I couldn't get it to work. The values fluctuated between 50-150 and refused to settle on any value.
Seems to work perfect for me; it reported 68, and I counted 66 manually (by counting the number of beats myself in 10 seconds and multiplying by 6). For reference, I have an iPhone 4 and it utilized the flash.
In any case, the software also shows a visual indicator of when it detects that your heartbeat, and it graphs your heartbeat over time. It's obvious from feeling your pulse while using it that it's correct, at least in my case with my phone.
2/3 of the people who responded to the poll on the site say it's accurate but I wonder what equipment they have on hand to let them know that what they believe to be the rate actually is.
I think if people are resting and see something between 50 and 80 b/m and then see 120-150 when exerting themselves, the device is probably accurate. It doesn't have to be perfect.
how would that work? I can understand how pulse is detected, as you are measuring the differences from second to another and finding a pattern. But how would you know what correlates to a particular level of oxygen in a particular person?
See http://en.wikipedia.org/wiki/Pulse_oximetry for more information, but basically you measure the difference in absorbance between two specific wavelengths of light (one is near-IR and might not be captured by a cellphone's camera) over time. The difference tells you how saturated your hemoglobin is (most of which has oxygen bound to it).
Pulse oximetry is one of the more reliable/least invasive/cheapest methods of determining pulse rate. Additionally, there's a massive market opportunity for extremely cheap PulseOx sensors that keep a data history: busy hospital emergency rooms would love to slap such a sensor onto the finger of every patient that comes through the door (and subsequently has to sit and wait). When a patient crashes while sitting in the waiting room the pulse ox sensor would be able to give the nurses and doctors a little bit of information about what happened that lead to the crash.
From what I've read it simply takes the ratio of absorbance from the systole and diastole and considers that a stable non-linear estimator of %SpO2. The device itself needs to be calibrated to get the non-linear fit in place, but each individual is assumed to be (in gross measure) similar enough to get meaning out of it.
Of course, there's going to be huge variation across finger types, blood volumes, lighting conditions, placement. I wouldn't consider them to be accurate much more than those impedance-based body fat percentage computers. In both cases, huge discrepancies from healthy values are still telling despite small-scale noise.
