Small, Light-Weight Speed/Distance Sensor for Skiers/Snowboarders

Performance analysis devices are ubiquitous tools in modern athletics. Such devices have seen little exposure in snow sports, particularly skiing and snowboarding. The objective of our project is to design and prototype a speedometer for skiers, using Doppler speed detection. This is the third iteration of the device at MSU, sponsored by the Air Force Research Laboratory.
Our goal was to develop a device that has the same utility as a pedometer, but with safety and energy saving features for our unique application. The device must measure the instantaneous velocity of a user and record velocities for a given run. At the end of a session the user must be able to access maximum and average velocity data for each one minute interval of the run as well as the total distance travelled. Temperature and power considerations for this project are crucial; the device should operate at a minimum of -10°F with 2 hours of battery life (while recording). The speedometer must also be capable of data transfer to an external device for performance analysis. 
For the fastest turnaround time of a prototype the design team chose to purchase a prefabricated Doppler module and design interface circuitry to convert the frequency shift from the module output into a DC voltage level to be read by the microcontroller. The user interface was designed for ease of use and comprehensible data interpretation. Our design must save power by turning off components at key times during operation, allowing for longer battery life.


http://www.egr.msu.edu/classes/ece480/goodman/spring10/group05