1. Looks good, and it uses lasers! :O

Posted at 4:45AM on May 23rd 2007 by Wolfmankurd

2. Nice, i just made a similar project for school and i program it with a PLC. And i know that it takes a lot of work to build such a thing. Nicely done.

Posted at 6:27AM on May 23rd 2007 by Gj

3. you have to love MIT's media lab. i'm a big fan of their OLPC (One Laptop Per Child) project.

Posted at 3:27PM on May 23rd 2007 by PowWeb

4. I was about to reply to the author, but then noticed the date.... so I'll stick my reply here.

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Hi,
Interesting little project....

Did you consider a spining multifaced mirror (rather than an osscilating flat one) this would be easier to drive and wouldn't have the 'flapping' forces.

One thing to notice is that as the mirror surface is not on axis that angluar speed of the reflected light would not be constant - but this can be compensated if you can modulate the source light and time the pixels appropriately. If it seems that I know too much, it's because we almost used a similar system but couldn't modulate our source (UV Laser) appropriately.

Another idea (shee's I'm full of them ;-) I had while typing is that you could introduction a secondary 'spinner' to do the vertical scanning from a signal point source (diode laser?).

This could be a 1 pitch screw with a 45' face to it, spinning at 1/N th of horizontal scanner to give appropriate vertical resolution.

Did that make sense? do you want me to sketch to explain further?
Munge.

Posted at 10:27PM on May 23rd 2007 by Simon Wood

5. Munge

Sketch Please

Posted at 6:16AM on May 24th 2007 by Navid

6. Thats a nice project. Munge, I had some ideas of doing a similar project, but rather than having the two mirrors linked so one was going an exact multiple of the others speed to get a certain resoloution, I was going to use two independant motors, going at fairly different speeds, each of which had an optical sensor to detect rpm. That caused the "point" to randomly move around them image area, and if it was moving fast enough it would cover all areas. The circuitry could modulate the signal using the optical sensors to estimate the current position of the point, and then using a lookup table to find the right data in a pic. The benefit of using this design is a relatively high resoloution possible without getting "flickering" of progressive scanning, while avoiding the mechanical complexities of doing interlacing. The problems with the design are:

I didn't have anything pic-like which had enough memory and a high enough clock frequency to make this effective for the sorts of resoloution I was looking for (300x300), especially since I wanted a moving image rather than a static one (so the pic also needs to read the data in from a data source, like usb, high speed serial, or some flash memory).

The total intensity of the laser is spread over the entie area of the "display" - that means it wouldn't be visible in anything but the darkest of rooms, unless you used a more powerful laser diode, which start top get hard to get hold of.

Posted at 7:33AM on May 24th 2007 by Hello1024

7. you can get faster and easer results by intergradeing a different microcontroler like an avr or a arm

Posted at 10:19AM on May 24th 2007 by alex mccown

8. http://www.pactecenclosures.com/Plastic-Enclosures/T-Series.html
one of thease might work for a good handheld inclosure

Posted at 4:13PM on May 24th 2007 by alex mccown

9. inclosure = enclosure in english...

Posted at 1:56PM on May 25th 2007 by Hello1024

10. Why use a recipricating mirror when a spinning one would yeld less vibe?
Would potting the diodes help with the exposure issue?
How about using metalized plastic to save hieght and gain reflectivity?

Posted at 5:21PM on May 25th 2007 by charles