What Wearable Technology Can Do

1.1 What is a wearable?

A wearable is a small device worn on the body, like a smartwatch or a fitness band. It senses things and tells you about them.

1.2 Which tasks do they really do?

• Location: a GPS receiver works out the position.
• Sleep: sensors estimate sleep from motion and pulse.
• Hearing help: a sound becomes a vibration or flash.

UPSC asked about all three in 2019. All three are genuine tasks.

2.1 How does GPS find a position?

NASA says GPS has at least 24 satellites. Receivers process the satellite signals and calculate position and time.

2.2 Does every wearable have its own GPS?

No. Rings and basic trackers often have no GPS chip. They use GPS data sent from the phone via Bluetooth. Many running watches have their own chip and antenna.

Source: freeCodeCamp, how GPS works in wearables.

2.3 What does built-in GPS cost?

Own GPS is more convenient. But it uses much more battery during an activity.

3.1 Which sensors are used?

A scoping review of sleep wearables found a trend towards combining two kinds of data. These are accelerometer data and PPG data.

3.2 What is PPG?

PPG is photoplethysmography. It uses an optical device. Light is used to detect blood volume changes in tissue.

3.3 What can it tell us?

Sleep follows heart and breathing patterns. A review says PPG can catch these changes. So sleep stages and breathing patterns can be inferred. Models must be tested and validated first.

4.1 How can a device help?

NIDCD says alerting devices use sound, light, vibrations, or a mix. Visual alert signalers watch doorbells and telephones. When the phone rings, they vibrate or flash.

4.2 What can a smartwatch do?

Apple says its watch can listen for sounds, such as a doorbell, siren or crying baby, and notify you. This is on Series 12 and Ultra 4.

4.3 What is the warning?

Apple says not to rely on this in emergencies or for navigation.

5.1 Are wearables becoming medical tools?

Yes, in some cases. In May 2023 Samsung said its irregular heart rhythm feature had FDA clearance. It watches for rhythms that suggest atrial fibrillation. This blurs the line between fitness and health monitoring.

5.2 Why is battery the limit?

More features need more power. Which? found that a workout turns on power-hungry features like GPS. In its test, smartwatches lost almost 9 days of battery life. One Galaxy Watch normally lasting over two days died in under 15 hours.

6.1 What did UPSC ask?

UPSC Civil Services Prelims 2019 asked which tasks wearables accomplish: location identification, sleep monitoring, and assisting the hearing impaired. All three are right, so the key is 1, 2 and 3.

See Q95 of UPSC CSP 2019 GS Paper I. You can also open this question page.

6.2 Which mix-ups come up?

• All three tasks are genuine. Do not drop one.
• Not every wearable has its own GPS.
• Motion alone gives sleep or wake; light sensors help with stages.
• GPS use drains the battery.