Wearable are electronic devices which are small and light weight so can born by the user. They are getting adopted as watches, fashion accessory, fitness tracker, security devices or specialized medical gadgets. A wearable device may be independent in its functioning or it may act as accessory to other device such as tablet or Smartphone. In this case it is mainly used as input or output device with some computing power.
Historically, watches and wearable calculators have been very popular but with the emergence of Bluetooth low energy connectivity, low power technology and sensors wearable are available in various forms such as Smart watches, wrist band, jewelry, arm band, connected clothes etc… This article will elaborate more on wearable architecture and the innovative technologies which are transforming our lives.
As the name suggest wearable are worn by user for an extended period of time and continuously remain on and connected. So a typical wearable device should have following attributes.
Wearables are continuously on the job and monitor or output key data for the user. They may have sleep mode but never OFF.
As wearables are miniature devices and run on small battery they should consume ultra-low current. A wearable device which requires frequent charging will lose its purpose. The emergence of low power technologies has enabled the revolution in this industry.
As they are worn by user they should be small enough to take various usable and aesthetic forms. A bulky device will be extra burden on user and will lose its acceptance.
Environment sensing is emerging as a key driver for wearable acceptance. Today wearable devices can monitor not only user activity information but also temperature, humidity, UV radiation etc.
Wearable devices should be intelligent enough to filter out noise from the real data. They should be able to alert user when any important information needs to be shared. For example, a security wrist band should be able to send alert when user has met accident or need SOS help.
Connectivity is the most important factor for emergence and acceptance of wearables. These devices can be connected to smartphones or tablet using technologies such as Bluetooth, wifi etc. Besides, they can also be connected to GPS satellites to monitor user location.
A typical Wearable architecture comprises of following elements
- Sensors – Digital and Analog
- Analog Front-end
- Power Management
- LCD Interface
The article will address first five elements of wearables.
Sensors are driving the emergence of innovative wearable gadgets. Some of the most popular sensors are mentioned below
Also called a g-sensor, accelerometer can be used to detect linear acceleration, vibration, tilt, free fall detection etc. Accelerometer is used to implement features such as horizontal levelling, antitheft, vibration alert, pedometer, remote monitoring of adults and kids etc.
Gyroscope measures angular velocity and used to implement features such as gaming, 3D mouse, athlete training etc.
Magnetic Compass can detect earth’s magnetic field and can give direction sense to devices. It is widely used in indoor navigation and map navigation in mobile phone.
Ultra-compact high-performance e-compass : 3D accelerometer and 3D magnetometer module
Pressure sensor can detect earth’s atmospheric pressure. This feature can be used to implement barometer and altimeter. LPS25HB pressure sensor from STMicroelectronics is so accurate that it can even be used to tell the floor of building accurately. This feature can be used to implement indoor navigation, augmented reality and 3D GPS.
Temperature and Humidity Sensor
Temperature and humidity sensor can detect temperature and humidity parameter which can be used to control the performance of devices as well as wearable gadgets.