actually we have our mega project as wall crawling plotter . In which the ckt diagram as well as its hardware its too hard to understand so i need help in that. Email ID:- shridharnakade@yahoomail.com

Journeyer made a HG2G reference... I'm now happier...

Just wanted to say... whomsholly glabbergurby splutterfligghop slartibartfast 42

That is awesome... How do I write on it?

ah. there should probably be some sort of "comment posted" notification since new comments aren't posted within view of the entry form.

Rig it up to a camera and have it draw chuck close style portraits. You have a very unfriendly captcha system.

Rig it up to a camera and have it draw Chuck Close style portraits.

Rig it up to a camera and have it draw Chuck Close style portraits.

What an awesomely simple/simply awesome project! A few notes: 1) If you hang the weights inside a piece of PVC pipe, they won't swing and the whole thing will look more polished. 2) If you connect cables to the bottom corners of the head, down to pulleys at the bottom corners, then up to pulleys at the top, then finally to weights, it should steady the head better. 3) It shouldn't be difficult to expand the head to use multiple markers, so you can draw in color. Instead of a solenoid for each pen, you could a) mount the pens in a circle b) have a stepper motor/servo in the center with a disc with one tooth c) mount the motor/disc on a solenoid When switching pens, the solenoid is released, the disc is rotated so that the tooth is above the proper pen, and then the solenoid pushes the disc/tooth/pen down. (The software would need to calculate the physical offset of each pen.) This same method would work just as well for different thickness of pen. For example '114' might be 'fine blue', while '714' might be 'fat blue'. Personally, though, I would measure the width of the line in mm and use the (00-99)RGB value of a square of each marker as the WWRRGGBB number for each pen. It's a bit more prep work, but will make it easier to program. Another way to do it would be to create a holder for each pen that would lock together with the other holders in a line. You could have different size holders for different sized pens. The holders don't have to be anything more complicated than plastic tubing attached to a stack of three plastic sheets offset in a tongue-and-groove setup. A special piece with a copper pad would attach to each end of the strip to electrically indicate each end. That way, you could easily have from 1-XX pens, without needing to make any changes except adding/removing holders. Instead of the motor rotating a disc, it would have a gear that would slide the strip of pens back and forth to put the proper pen in place. No matter which way you decide to go, by telling the software the WRGB number of each pen as you put them in place, it could decide on its own which color/width of pen to use. 4) If you have a metal whiteboard, you could mount rare-earth magnets to keep it firmly attached to the board and use the nibs of ballpoint pens on outriggers (to keep them as far from the fresh ink as possible) as microbearing spacers to keep it from smearing the ink. If the whiteboard isn't metal, you could have a separate, flat, synced head on the back of the board with magnets mounted on it.

About the camera. Try a tused Playstation eyetoy. You can buy one for around $5.00 USD a a gaming store, and its a pretty high quality web cam. Just have to get some drivers, but you can google for how to get those.