A MEMS based accelerometer gives the magnitude of vibrations experienced on the floor. This is read by the microcontroller connected to it. The acceleration magnitude, after some basic preprocessing, is logged on a microSD card also connected to the processor. To geo-tag the acceleration data, a small GPS receiver is connected to the microcontroller. The GPS data is also appropriately stored with the acceleration data.
Since only the location data, number of satellites in view and ground speed was needed, the device has been configured to give only GGA and VTG strings. The GGA string contains all the information about the position, time and number of satellites. The VTG string contains the speed and heading information. The following figure shows the path traced using the SanJose module. The red pointers show the location of jerk during test drive in IIT Kanpur.