Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

The Polygon mirror, with its motor and the special comb to provide for the signals of the position of the mirror, can be found in early, non LED Laser printers from IBM, Unisys, Univac and Siemens (and some others that I have forgotten the names of!).....ones from around 15 to 35 years ago. You need to find a breakers yard that specializes in such items......it simplifies the scanning dramatically.......
Its actually quite an easy system to work with......modern electronics being what they are.....
As someone else also pointed out, laser safety glasses are a must at ALL times.....
The only other way I can think of using the laser is an X-Y system using fine stepper motors and angled mirrors on the shafts, on for the x and one for the y. Disco's use a similar (but not accurate enough for this work) system to write on walls with laser light. Then I am sure that software could be easily written to control the laser on and off and also to scan. In fact you really only need to drive one motor at a time, so software could be very easy, connected via a parallel printer port card to the stepper drivers. Stepper motors are around that have 400 steps per revolution, which may or may not be fine enough, but using say T5 toothed belts and pulleys, it would be quite easy to multiply that by 10:1 gearing. There is also microstepping, which can chop the steps of the motor up by quite large amounts, 16 microsteps per revolution is quite normal for 200 step motors, which are very common.
If you go in this direction, do buy the best motors that you can find so that the steps are as accurate as possible....
Furthermore, it may be a good idea (if this direction is chosen to open up a new blog just to construct such a system......just a thought or two......
Also, instead of scanning, one could use vector graphics to cut out the PCB. Both systems could be tried out using the same hardware!!!
That my multiple 2 cents worth, have fun!
Greetings from
Andy Mathison

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