Spire's Wearable Health Tags Now Available in Apple Retail Stores

[smirking]

So how does this do heart rate tracking? Do you need to have it strapped near your chest for that or do you need full skin contact for it? If it doesn't require either, I have doubts about the effectiveness of its heart rate tracking as the kind of tracking done with the Apple Watch, Fitbits, and other wrist worn activitiy trackers are all borderline accurate or flat out inaccurate for exercise. If it doesn't do that well then it's just one of the clip on Fitbits with an expiration date.

 

[routine_analyst]

I wear (wore - the face finally popped-off) my Apple v1 watch only when I leave the house. (I've ordered a V4, I won't have it for a while, because I chose the Nike, just for the band). And not even every time I leave. I especially don't like wearing the watch, because I find the band a bit uncomfortable, and especially so while I am coding.

So, my Apple Watch is useless as an overall activity tracker. I have occasionally used it during sports activities.

I think this tag is a great idea for those of us who don't wear the watch full time, and the price is quite reasonable.

Buying one for every pair of underwear is a stretch, though! I don't know why you would need an "n-pack" unless buying for the whole family.

I hope they have a good algorithm for washing-machine detection, so that they don't inadvertently give you credit for all that tumbling.

yay!

 

[jtara]

So how does this do heart rate tracking? Do you need to have it strapped near your chest for that or do you need full skin contact for it?

I can't tell you how they do heart rate tracking, but I can make a good guess, based on my own experiments.

A couple years ago, I was investigating the use of an iPhone for respiration monitoring. I wanted to write an app to help people discover possibly undiagnosed sleep apnea.

We started by finding an already-existing app for recording iPhone sensors, and we did several test sleep sessions. We initially thought that the best place to put the iPhone would be laying on the subject's chest. We experimented, and found that actually the best place is on the stomach. We used a "sports wallet" (basically a thin fanny-pack) to secure the iPhone in place.

This was about the time that Samsung phones started catching on fire. We abandoned the project for obvious liability reasons. We decided it was not prudent to encourage folks to sleep with an iPhone on their stomach! It needs to be a smaller device with a smaller battery with less potential for disaster.

Anyway, not only were we able to get a reliable signal for breathing, but to my surprise, we could also get a reliable heartbeat. Both were visible to the naked eye in the plotted data, though the heartbeat was a bit muddy. Both could be reliably recovered with Fourier analysis.

The position at the belt-line shown in the photo would be ideal, according to our findings. An accelerometer could easily pick up both respiration rate and heart rate at that position, at least for a subject sleeping on their back. Standing, I dunno, might be possible.

 

[smirking]

I can't tell you how they do heart rate tracking, but I can make a good guess, based on my own experiments.

Hmmm, thanks! That's very insightful. I'll have an ear on the ground about how devices like this perform. If a remote sensor extends the capabilities of an Apple Watch to sleep tracking and things that are hard to do with only 24 hours of battery life, I will probably finally get one.

It wouldn't matter to me if this sensor's heart rate or respiration rate tracking doesn't work well for exercise or just being up and about. If paired with an Apple Watch, the Apple Watch can do that just fine... or rather just as poorly as everything else that's not a chest strap heart rate monitor.

Speaking of which, do you have any thoughts on whether having a wrist worn heart rate tracker plus a lossy and noisy belt worn tracker like this one could combine together to provide more accurate high intensity heart rate tracking without requiring a chest strap?

And do you know of any sensors that measure body temperature? That's one thing that I hardly ever see in wearables. I've looked far and wide for devices that include temperature sensors, but I think the only one I found that had it was the now defunct Microsoft Band. I'm interested in having body temperature for sleep quality tracking purposes.

 

[jtara]

Speaking of which, do you have any thoughts on whether having a wrist worn heart rate tracker plus a lossy and noisy belt worn tracker like this one could combine together to provide more accurate high intensity heart rate tracking without requiring a chest strap?

Google "sensor fusion". It's done all the time, e.g. in navigation apps to combine GPS and inertial sensors. A Kalman filter is one of a number of techniques that can be used.

Your intuition is right on here. From Wikipedia:

"Sensor fusion is combining of sensory data or data derived from disparate sources such that the resulting information has less uncertainty than would be possible when these sources were used individually."

This can be true even when the different sources have varying degrees of accuracy and certainty. It's a case of "the more the merrier".

BTW, the apps we used for study are "Sensor Data" and "Vibration". Vibration has built-in Fourier analysis.