We were very interested in doing something with Bluetooth and so we thought it would be really cool to spatially locate a device in the world using the signal strength of a few receivers.
What it does
Find any tech that is capable of being discoverable via Bluetooth and can locate them in a room. They don't even need to be paired to our network.
How we built it
In order to pinpoint the location of a device in 2D space we needed to create a geometric plane by which they could be mapped. We used 3 DragonBoards that simulated receivers that scanned the room for Bluetooth devices in question which are discoverable. Using trilateration, we can find the intersection points of the three RSSI magnitudes emitted from the receivers. Each receiver sends our centralized AWS server the device and magnitudes associated with it so we can uniquely identify each device and their location.
Challenges we ran into
Designing the algorithm to pinpoint the physical location of devices is incredibly difficult. Simple magnitude calculations are not sufficient and so we had to be very cognizant of the location of our receivers.
Dealing with the DragonBoard and its limited power/memory was a huge limiting factor. We needed all the receivers to be able to communicate with each other before defining the location of the device in the room.
We also came to a difficulty with the DragonBoard and its Bluetooth adapter. It would not allow for simple BLE so we had to manipulate Android's Operating System to allow for discoverability for a persistent amount of time.
Accomplishments that we're proud of
Using trilateration and rssi to define distance and essentially location of any tech in a room using only three receivers. Believe it or not, but creating a one button android app that allowed for the phone to be discoverable using Bluetooth.
What we learned
Learned how bluetooth works in a more in-depth way and learned how triangulation works.
What's next for Marauders Map
Multiple devices would be able to be located within a room, making each point on the map a persons face or a specific face to define a room layout of people.