LED/Laser Diode Characterization System
The goal of this project is to create an easy-to-use curve tracer for Oregon State University’s optics laboratory. The device will be reliable, safe (to the user and the device under test), and output the diode characteristics to a graphical interface.
Currently the optics labratory is analyzing device characteristics such as polarity and current vs. voltage (I-V) curves of diodes through the use of an antiquated curve tracer. The current curve tracer is tube driven and lacks the ability to store measured data. Tubes are currently worn to the point of producing inaccurate results. Since tubes are expensive, and this device is used frequently, a more robust and reliable design is required.
Our solution is to incorporate a micro-controller and computer interface to allow for a reliable portable device. Utilizing Op Amps as a current source instead of the bulky tubes will help reduce cost and size. The new curve tracer will feature automated as well as manual measuring of I-V and light intensity vs. current (L-I) curves. By designing an easy to use, compact, and accurate curve tracing device we will allow characterizing of LEDs and LDs to be simpler for the user.
Building off of the principles of laser diodes we've chosen to also design a free space communication device as an optional project if time and funding permits. By understanding the characteristics of laser diodes we will modulate a laser diode to transmit an audio signal across a distance of at least 30 feet. A device that can achieve short range communications can be beneficial in home and commercial use in place of running a copper conductor.
- Able to measure and output an accurate I-V curve for LEDs and LDs.
- Able to carry out all functions regarding LED and LD testing without damage to LED/LD.
- Able to determine correct polarity of LEDs or LDs.
- Able to measure and output an optical power vs. forward current (L-I) curve for LEDs and LDs.
- Provide an easy-to-use user interface.
- Ability for manual measurement.
- Ability for automatic measurement.
- (Optional) Design and build a small, laser diode optical communication source to transmit MP3 audio files.
6.1 Testing Evidence