How wearables work


As a society, we’re becoming increasingly saturated with smart technologies; fitness bands that track our heart rates, bank cards that strap to our wrists, and VR headsets for gaming to name a few. With so many cool wearable technologies on the market, haven’t you wondered, “how does it work?” 

How do contactless payments work?

Westpac’s new wristband wearable is equipped with a tap and go style reader, which means we can spend up to around $100 without having to enter our pin number or even carry your wallet or phone. But how do they work? These wearables and our contactless bank cards contain the same technology: a little chip and a little antenna. These are powered up by a power signal emitted from the POS. The wearable then transmits radio signals back to the card reader, and the devices begin to communicate. The chip reader sends an encryption key, and the chip itself responds with the same unlocked encryption key. More of this wireless communication from the devices occurs, including the swapping of transaction details and storing of a ‘receipt’, all in just a few seconds.

How do fitness devices work?

One word: Accelerometers. At the core of most fitness wearables is an accelerometer. Good quality accelerometers use three or more axes, with a moving component in between. Imagine the little air bubble in a building level, operating in 3D. The wearable uses the information gathered from the activity of the moving component to determine the movements of the wearer. The algorithms used by each different branded wearable are a closely guarded secret, and can change wildly between brands

More sophisticated fitness wearables often have little add-ons like a heart monitor or GPS. Heart monitors in wristband wearables don’t use the electrode method of patch style heart monitors that stick to the skin. Instead, fitness bands use green LED lights on the underside of the band that shine through the skin to visibly monitor blood flowing through the veins. Cool, huh? GPS works by cross referencing 3 different satellites to determine your longitude and latitude via microwave signals. The time between signal sent and signal received from the satellite to the phone calculates your distance from the satellite, and continually tracks you by pinging back and forth between the two.

How do virtual reality headsets work?

The aim of virtual reality is to mimic the feel of real world immersion, like you’re inside the game and not viewing it from a box with visible boundaries. The first step in this illusion is stereoscopic picture. The headsets overlay two slightly different images in front of each eye, each seeing the picture at a slightly different angle. This mimics the way our eyes see the world and gives the illusion of depth. An accelerometer then maps your head movements to control the navigation of the image. The images need to move at a minimum of 60fps or the device risks inducing ‘virtual reality sickness’. These effects combined give the overall authentic feel of virtual reality.

-Eliza Brockwell

Find out more about the science behind social media.

westpac wearables

Westpac just launched its new ‘PayWear’ wearable bracelet, shown above.

fitbit wearables

Fitbit (pictured) tracks your heart rate through green LEDs. The green light is absorbed at a higher rate with more blood flow, and less light is absorbed with lessened blood flow. The watch calculates this rate of light absorption to determine your heart rate.


VR headsets, e.g. Oculus Rift (above) track your head movements through accelerometers and stitch together two different images to give depth.

Eliza Brockwell

Author: Eliza Brockwell

Eliza is passionate about creating content that encourages diversity of representation in STEM.


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