Brief

We developed an smart commercial vehicle tracker for one of our main customers. The aim of product was to save fuel costs, reduce accidents and lower insurance costs.

Implementation

The tracker had:

• A GPS receiver
• GPRS modem
• three axis accelerometer sensor
• iButton driver ID reader
• 1-Wire bus for temperature and other environmental sensors
• Flash memory for data logging
• USB interface
• Internal battery monitoring and charging control
• ARM Cortex M3 processor

Low power was a key requirement as was an efficient data exchange with the central server in order to minimise GPRS data charges. The accelerometer was used to wake from low power mode, detect break in, detect tow away or accident and to monitor driver behavior. The customer had their own server side so we implemented their server protocol in our firmware. Data was logged to flash memory in a robust way (power fail safe) supporting circular logging where when full new data replaced oldest data — all the time supporting logging while sending to the server. The sending of data to the server used a dynamic payload size that adapted to the network reliability hence even on poor network connections data still got through. The smart tracker would download firmware updates from the server.