A beacon is a small computer. Its 32-bit ARM® Cortex M0 CPU is accompanied by accelerometer, temperature sensor, and what is most important—2.4 GHz radio using Bluetooth 4.0 Smart, also known as BLE or Bluetooth low energy.

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The greatest advantage of Bluetooth Smart over the previous iterations of BT technology is how energy efficient it is. Thanks to that, and to a lot of work our engineers put into power management, Estimote Beacons can last more than 3 years on default settings on a single CR2477 battery.

Don’t confuse Bluetooth Smart with the first version of Bluetooth: the one that required pairing and never actually worked. It’s a new standard developed by Nokia™, now implemented in all modern smartphones like Apple iPhone™ or Samsung™ Galaxy S. Other devices, ranging from Fitbit fitness trackers to the Apple Watch, use Bluetooth Smart too.

Bluetooth SIG maintains a list of Bluetooth Smart devices.

Signal range and measuring proximity

You can think about the beacon as a small lighthouse. But instead of light, it uses radio waves, and instead of ships, it alerts smartphones of its presence. Estimote Beacons have a range of up to 70 meters (230 feet). The signal, however, can be diffracted, interfered with, or absorbed by water (including the human body). That’s why in real world conditions you should expect range of about 40–50 meters.

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Phones or other smart devices can pick up the beacon’s signal and estimate the distance by measuring received signal strength (RSSI). The closer you are to the beacon, the stronger the signal. Remember that the beacon is not broadcasting continuously—it’s blinking instead. The more frequent the blinks, the more reliable the signal detection.

And because Bluetooth Smart doesn’t require pairing, a phone can listen to many beacons at the same time. This unlocks more opportunities: for example indoor location. (Estimote 2015)

 

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