Gait Measurement Timer

This device is used by the Framingham Heart Study to measure the walking gait of study subjects over a fixed course. Two infrared light beams provide a precise measurement of the time interval required for the subject to cover the course. The time of day is displayed along with two successive time measurements.

The device was build on a custom PC board using an Atmel microcontroller with a back-lit LCD display. The unit may operate on batteries for portable use, or wall power for fixed use.

[Engineering Technical Documentation]

Gait Measurement Timer 1

Gait Measurement Timer 2

Gait Measurement Timer 3

Gait Measurement Timer 4

Gait Measurement Timer 5

Gait Measurement Timer 6

Time Reversal Mirror Single Channel

In a time-reversal system a wave is sent out into a medium by one or more elements in an array and then the echo signals of each element recorded. A section of the echo signal recorded by each element is then selected and played backwards through the same element. The physics of wave propagation results in the signal refocusing back onto the target that scattered that signal. The applications that this could be used for include tracking kidney stones in the body and finding buried mines in the ocean.

This device can send and receive arbitrary waveforms with controlled timing to a single ultrasonic piezoelectric transducer.

[Engineering Technical Documentation]