Wow thank you for the input. The device was only meant as a curiosity. If I wanted accuracy I would strip most of the speaker cone out and drive it from a well damped source, one that can deal with the effects of the return (Back EMF) current from the coil and probably use that information for positioning feedback, much the same as most real motor speed controllers so...
No this was only meant as a "Wow Golly Gee...." kinda thing. I have always been fascinated with those "Text Scanning Displays" where the text seems to float...
I have one of those Sure Electronics 3208 8 X 8 X 4 matrix displays as well but I thought that the "Writing on the Wall" concept was really irresistible.
A simple "well defined" ramp generator and a means of switching the laser (0.5 mW ONLY) on and off... sure looked like a great way to use up a week or so... I'm a Retired Auld Phart, probably with too much time on my hands. The "Raster Scanner" has been around for a long time... Television before the digital age. The only real issue is 'distorting' the ramp to 'paint' on "non-linear" surfaces. This almost comes into the area of
"Self Correcting Optics" . If nothing else it is an interesting and thought provoking area of endeavor.
I bought my first transistor at age 14, I grew up fixing vacuum tube equipment. I remember the First real digital watch and the first calculator too. I will be 66 in June, Fat and Sassy and lovin the life I lead and I have a Long memory...
And I talk too much.
Doc