Measuring Table

In order to provide a proof-of-concept, we decided to collect measurements along a hallway, create a reference map, test it over and over to see if the readings match.

I designed and built data collection apparatus which consists of:

1. 3-Axis Compasses with Algorithms: This is a magnetic sensor that produces magnetic readings with five outputs: Heading, intensity, x-axis, y-axis, and z-axis.

2. Stepper Motors: Used in order to divide a full rotation into a number of steps, so as to allow for the collection of readings with headings towards many directions.

3. Arduino Pro Mini: Used to control and organize the collection of magnetic readings and the exchange of data with the CPU.

4. Arduino Bluetooth mate: used to receive and send information to the Microcontroller.

Those electromechanical components were assembled in two Lego towers on a portable table. The table was moved along the 120-foot long hallway in 2 ft increments. At each point, a full 360 rotation of the tower would take place in order to gather as much data as possible.

Results

The confusion matrix in the image below displays how well the tested set readings matches the reference map. In other words, the matrix shows the confidence in determining the fingerprints according to the consistency of readings over repeated measurements. It is evident that the respective points along the hallway have much better confidence in matching with each other than the rest of the set of magnetic fingerprints.