Crownstones know where you are if you carry a smart device with you such as your smartphone. Your smart device measures the Bluetooth Low Energy signals emitted by the Crownstones. This makes it possible for the Crownstones to react to your presence and proximity. This ability is called indoor positioning (or indoor localization). To enable this feature, you need to have a minimum number of Crownstones and train them by walking a few rounds in a specific room. You do the same in the rest of the rooms so the Crownstone’s AI can learn in which room you are!

Four Crownstones in the home is the absolute minimum. The more Crownstones are present, the more information the Crownstones have on your location. The localization works best with at least two Crownstones per room. The Crownstones in other rooms also contribute to the positioning accuracy because the Bluetooth signals go through walls. Hence, two Crownstones per room is often sufficient (the Crownstones in neighbouring rooms are participating as well).

For the Crownstones to detect your presence it might take up to 10 seconds, which means that if you walk along the hallway to get to the toilet, the lights at the hallway won’t automatically turn on. On the other hand, if you stay in the hallway for a longer time, the Crownstone will realize that you actually are in the hallway and the lights will turn on.

Crownstones detect that you leave the house after not hearing from you for 5 minutes. After that time, they will think that you have left home (the sphere). Once a room is no longer occupied by anyone, a five-minute grace period starts. The five-minute grace is to avoid turning lights (or devices) off and on when you are still at home, but there is a long delay when your smartphone advertises your location to the Crownstones.

It’s difficult to put a number (in meters) for this answer as the accuracy depends on several factors such as the number of Crownstones present, how the training was done, the presence of metal appliances or the presence of people, etc. A more detailed explanation of this topic can be found in this post.

To improve the quality of the training, we give the following recommendations:

• Try to cover evenly most places in the room.
• Hold your phone the same way you do when not training.
• Try to hold your phone not always in the same orientation.
• Re-train a room when a Crownstone is moved to another place inside the room.
• Re-train a room when a Crownstones is added or removed from that room.