The beacon, lighthouse of the XXI century

Image result for lighthouse


We live in a digital age, but we are still at the dawn of the technology. Every year, new inventions are made, some of which come into existence because of the steps made before. In other words, there is a road to be followed. The simplest way to advance is to mimic what the nature does or what man has done before with  an earlier technology. One such example is the lighthouse.

Image result for circularA bit of history

Invented in the antiquity, the lighthouse has been for centuries  the savior of the sailors navigating by night. For more than 2000 years, the technology remained  virtually the same: a tall building with a powerful light at his top. In order to cover a circular area around the structure, the light was mounted on a rotating wheel. Thus, the lighthouse was useful to anyone within the range.

We note that the ships move all in a 2D plane, in a circular area centered on the lighthouse). We will see later 3D usages.  As every captain has a map with the coordinates of the lighthouse, he can identify his own position on that map, by using the beam of light and the information it provides, such as coastal shapes quickly illuminated by the beam.

Related imageModern equivalents

Today, the lighthouses still have the rotating beam of light, plus a radio emitter. This is beneficial, for ships can use radio navigation if they have the right equipment. If not, the traditional way of the lighthouse is available at zero cost.

Airport control towers are another example of modern lighthouses. They add a supplementary dimension.  Planes move in 3D space. The tower serves  not a circular area but a sphere centered on the tower (or more exactly the radio emitter). Also, the tower has some kind of signature that uniquely identifies it.

Image result for beaconThe beacons

We have seen the key elements of what constitute a modern beacon:

  • it emits a radio signal
  • the signal covers a spherical space centered on the beacon
  • the beacon identifies itself by emitting its own signature
  • the radio signal uses a standardized frequency range and modulation. Devices that are compatible can talk to the beacon.
  • the signal fades with the distance, thus we can measure the distance to the beacon.

Every beacon has these characteristics.

Image result for estimoteBluetooth beacons

During the  late 1990s and early 2000s, a new technology has become popular: Bluetooth. It is a short range (<20m) radio wave that allows two devices to communicate. For example, they could be two mobile phones. Next logical step has been to create small devices that  behave like beacons and use Bluetooth as main technology. Modern mobile phones can talk to Bluetooth beacons.

Uses of the beacons

We have the beacon, we have the mobile phone, what next ? A couple years ago I had the opportunity to test this wonderful combination of  Bluetooth beacons and mobile phones, during a hackathon. It was like magic. While the distance to the physical beacon had some measuring error of a quarter of meter, it had been clear to me that Bluetooth beacons  can precisely measure the distance up to a meter.


For those who are passionate, I will give a short list of beacon manufacturers. There are many providers and the list below is just a list:

I have used Estimote beacons and they worked well on Android. At that moment, there was no iOS API for them. For more information, there are many reference sites, such as QlikTag.

Image result for bluetooth ZS-040Do-it-yourself beacons

I  have bought some Arduino hardware. I will keep you informed of my personal IoT project: building an Arduino Bluetooth beacon. It is a new experience for me and I can’t wait to see in the Bluetooth module in action.


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