As far as the look is
concerned, the wrist-based wearable or watches that proffer heart-rate
monitoring aren’t much different from their analog or mechanical counterparts.
Undoubtedly, most of these gadgets have similar watch faces, wrist bands, and
even the equipment such as the PPG (photoplethysmography) sensor to make the
operations like heart-rate measurement possible. These sensors, which rest as
an essential component within the wrist-based wearable, often fail to detect
the heart-rate appropriately. Nowadays, most of the designers or manufacturers
of wearable gadgets suffer from losses due to this concern. If you are also one
amongst them, relax as this article has brought a precise solution to this
concern. Here, you will become aware of the challenges that these modern
devices can face, along with the appropriate way with which you can get rid of
the same. Building the wearable with an appropriate Industrial Design is one of the best ways to keep
these challenges at bay. Read below to see how.
Challenges
Amongst a lot of
challenges that the PPG sensor of wrist-based wearable can face, the most
common one is that while activities like jogging, the sensor even senses the
changes in the blood volume related to motion take place as the wearable press
and deform the blood vessels under the skin. It makes the PPG sensor to create
confusions by sensing and mixing up the ratings based on the changes in blood
volume and the reflected light intensity. Another factor that compels the PPG
sensor to generate ambiguities in heart-rate detection is LED scattering. In
the cases of repetitive arm motion due to running or jogging, badly designed
wearable creates an air gap amid the photodiode and users’ skin. This air gap
leads to scattering, and repetitive scattering can result in degrading the
cardiac-associated PPG element from the spectrum. It ultimately turns distinguishing
the required cardiac signal into a difficult task.
Measures to Resolve
Challenges and Enhance Accuracy of Heart-rate Monitoring in Wrist-based
Wearable
Providing wrist-based
wearable with the appropriate industrial design is one of the best ways to keep
them away from several challenges or glitches. The proper industrial design of
your wearable will let you achieve precise heart-rate monitoring outcomes. To
understand it better, go through the below example where two spectrograms – one
from a poorly designed watch and other from an optimized ID have been observed.
The two spectrograms are the outcomes of synchronized accelerometer signals and
PPG sensor signals recorded during treadmill running and slow walking. The PPG
signal relies on both the motion-related pattern and heart-rate induced
pattern, and therefore, the spectrogram of an appropriately designed
wrist-based wearable will show a precise spectral density of the accelerometer
and PPG sensor as per the optimal industrial design. In this case, the
heart-rate frequency is clearly visible, regardless of whether the user is
running or walking, and thus, is easily separable from motion frequency.
Nevertheless, in the case of wearable designed without focusing on proper
industrial design, the spectrogram showcases either faded or invisible
heart-rate. Besides, these poorly designed watches, if wore tightly, can stress
the blood beds under the user’s skin. It then decreases the blood perfusion and
generates difficulty in isolating heart-rate frequency and motion frequency
from each other. According to the statistics obtained through this example,
designing wrist-based wearable by emphasizing industrial design is imperative.
It requires working on several characteristics of ID, some of which are as
follows:
1. Optical distance
between the photodiode and the LED light source
The distance amid the
LED light source and the photodiode is a vital factor that determines signal
quality and light-source intensity (battery life). If the gap is short, the
photodiode will not receive reflected light from the blood. Nonetheless, if it
is large, then the reflected light will turn weak and lower down the
signal-to-noise ratio (SNR). Moreover, increasing the LED current blindly may
overfill photodiode’s output, which then fails to provide the information
required for heart-rate detection. So there is a need to maintain an
appropriate (neither too less nor too much) distance between LED light source
and photodiode.
2. Component’s
Weight Distribution within Case
Distribution of the
components’ weight is a factor essential for reducing the rocking motion of the
wearable. As users often prefer watches with scratch-resistant faces,
manufacturers’ preference for scratch-resistant glasses is quite high, but the
existence of heavy glass on the top covering all other components of the watch
exacerbates the rocking motion. Hence, both the component designer and Industrial Designer should work together to evade
this top-heavy weight distribution.
Final Thoughts
As per the above
information, we can conclude that precise heart-rate monitoring from wrist-worn
watches depends not wholly but widely on their industrial design. That’s why it
is crucial to emphasize the challenges and approaches to remove them at the ID
stage itself. Hopefully, the article has provided you with most of the
information that you need in this field. However, if you are still looking for
additional info, feel free to contact professionals who deal with rendering
services related to Industrial Product Design. For more
visit: https://www.trademarkmaldives.com
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