Power Point for the above video
Objective:
The objective of this project is to construct a laser range finder that can be used to measure various distances, ranging from 10, 50, and 100 ft. the end goal is to be able to expand beyond the ranges of feet and measure distance as far as the moon. Laser range finders have numerous practical applications ranging from surveying to targeting systems for unmanned aerial vehicles.
Design Overview:
The design we are using measures the relative phase shift between the transmitted beam and the received beam. This is accomplished by amplitude modulating the optical power of a laser diode with a sinusoidal signal (the reference signal). The returning beam will be detected with a photo-diode and converted to a voltage signal; this will be referred to as the measured signal. The reference signal and the measured signal will be mixed with a local oscillator to bring them down to a lower frequency. After mixing, the two signals will have the same relative phase shift but will now be at a lower frequency which will allow for more accurate phase measurement. These two, lower frequency, signals will be converted to square waves using a Schmitt Trigger and placed at the two inputs of a bistable multivibrator to create a pulse train. The duty cycle of the pulse train is proportional to the relative phase shift between the two signals.
Development In Progress:
Progress:
Our work thus far has been in constructing and testing the modulation source and the driver circuit for the laser and building a photo-diode circuit to detect the signal. We have constructed the Modulation Signal, the Current Source and the Detection Circuit.
Some Debugging of our circuits has been necessary to rectify some discrepancies in some of our collected data.A high frequency is required for measuring shorter distances which proved to be too fast for our original current source circuit design. This issue was solved by switching to a high bandwidth op-amp voltage to current circuit as well as switching to a laser with out a driver circuit.
Full Report:
Progress Report:
Final Project Progress Report.pdf
Team Members:
Paul Verrinder
Andres Castillo
Login