Bluetooth has been around for a long time, and nearly all new computers and phones have Bluetooth capabilities built in. We all have been using this technology for pairing our headphones, car stereo systems, and wireless keyboard & mouse.
The original protocol, now known as Bluetooth Classic, was developed in the late nineties for portable equipment and their applications. But recently, the protocol received a major update as version 4.0 or the Bluetooth Low Energy.
Bluetooth Classic worked well for paired portable devices, except that it required significant amounts of power. With the emergence of smaller always connected devices, such as fitness bands, there was a need for a lightweight alternative to the original protocol. Nokia developed the initial version of a new protocol that needed significantly less power and was suitable for small battery powered sensors.
This new protocol merged with the original Bluetooth in 2010, forming the Bluetooth 4.0 also marketed as Bluetooth Smart or Bluetooth LE (BLE). iPhone 4S, released in 2011, was one of the first phones to implement the new protocol.
Bluetooth vs Bluetooth LE
Bluetooth was designed to have low power consumption for implementation with portable electronics while providing high data transfer rates. Commonly used Bluetooth radio uses only 2.5mW of power and is optimized to remain switched off when not in use. But even at these low power requirements, the protocol as is was not suitable for small sensor devices.
Many new sensors and beacons don’t need the high data transfer rate provided by Bluetooth, i.e., music and audio applications. Instead, these sensors simply transmit small data values like heartbeat, calories burned, or distance information. As a result, Bluetooth low energy was developed to provide connectivity to these small sensors while needing extremely low battery power.
Bluetooth LE requires very little power. The iPhone 5 has a 1,440 mAh battery. A beacon, advertising its location using Bluetooth LE, can work for 5-10 years on a battery the size of an iPhone 5 with a single charge. While car stereo systems and handsfree headsets will continue to use Bluetooth Classic as they need high bandwidth, newer sensors are using Bluetooth LE. Some examples are smart-watches (Galaxy Gear, Moto 360), fitness bands (Fitbit and Jawbone UP), health monitors (Mio), and countless more gadgets (Lockitron, Nymi).
At WWDC 2013, Apple announced iBeacons as a proximity solution based on Bluetooth LE. We will be covering iBeacons in more detail in future posts.
