Laser diode from CD rom drive

Hi All.

Thought I’d introduce myself, my name’s Gareth and I’m an alcholholic, Oops wrong forum. I’m an under-grad from the UK and looking for some advice on my dissertation

It is titled
“Exploring the possibilities of laser diodes as sensing elements - This is a novel research to study laser diodes and their effectivness in surface topography sensing”

I’ve done the usual literature searches and rec’d a number of papers that show it’s possible. I’ve even found a product that does this, but I need to be able to take this one step further.

I’ve tried to use a (cheap) reclaimed Laser diode from a cd player and a cd rom drive to measure the topography of a surface based on a time response and herein lies the problem.

I don’t know enough about the workings of a laser diode or the associated electronics, to do this.

"what is needed in terms of amplification, filtration, noise removal. How would the beam reflect, or need to be reflected, do I need or is there software that allows a signal to be converted? how do I best power this of do I need a program to pigyback the drive using the pc.

In hindsight, this may have not been the best project for a mechanical course and better suited for electrical or mechatronics but it’s too late know.

Any help you can give or any advice regarding book, website etc would be very much appreciated.

gareth davies

well, the reflection of the laser depends on the wavelngth of the light and the thickness of the material you want to reflect it from, I dont think you can take any old cd laser and have it reflect off of any surface, however, I’m only taking high school physics so I may be wrong

The laser of CD Players use a lens in order to produce a non-parallel beam. It focuses of the CD surface and is reflected.
Thus I don’t think that you will get any signal if your sample is not at the exact distance where the beam focuses, and if it doesn’t perfectly reflect light.