The impending and eagerly awaited TomTom Runner 2 (aka Spark) has a TomTom-built optical HRM.
Is it any good?
We don’t know is the answer for sure yet. However some pointers can be gleaned from looking at the promo shot/image attached to this post.
The one in the official post is shown above and yet the one below from wired.it probably shows a more genuine non-photoshopped image.
Assuming the wired.it image is representative of the final unit we can see the following good features of the optical HRM
- Relatively OK-sized area covered by sensors
- Probably 3 lights
- Definitely more than one colour of light, green is best apparently
- A bevelled area to stop unwanted light/moisture ingress/digress.
So all that is great.
If you’re interested a bit more in what other sports watch vendors do with optical then look at (this).
The proof will still be in the pudding however. This is because the algorithms used in determining HR are the ones where gains in accuracy are made and lost. As well as the maths there’s all the frequency of sampling that comes into play too.