cubeberg 540 Posted June 19, 2013 Share Posted June 19, 2013 I ran across this Instructable the other day on how to make a tiny laser engraver from a couple of CD-Roms. I figured my wife wouldn't be too keen on lasers, and the glasses I would need are expensive - so I decided to start with a Pen Plotter. Maybe I'll work my way up to a laser I'm using TI's DRV8834 low-voltage stepper driver - the same one used by a TI employee in their internal boosterpack challenge. For now, I'm using a small breakout board, based on the boosterpack design. Using the chip honestly couldn't be easier thankfully. Right now - I've got two stages built and I'm working on the third. Running some test patterns - using some "Poster Putty" in place of the unfinished Z-axis. I'm using an old PC power supply for the 5v needed for the steppers - works great, although it's almost as large as the project itself For now - the code is pretty rudimentary - but it's a good start. Current X/Y/Z coordinates are recorded, and it supports moving to any X/Y coordinate - although it doesn't calculate a perfect line between the points. The Z axis is handled first since it's simply used for starting/stopping a line - no purpose in moving the Z axis at the same time as X/Y. From there - X/Y are incremented/decremented by 1 until it hits the desired value. So moving from 0,0 to 15,30 would result in a 45 degree line from 0,0 to 15,15, and a straight line from 15,15 to 15,30. I'm fighting with some issues with the platform being level - the pen isn't exactly forgiving - a variation of a single MM is enough to stop a line. I might work in some Z-axis compensation, but hopefully I won't have to. I've also run into some situations where the steppers skip - I think that might be a lubrication issue. Hopefully it isn't an issue with the pen dragging on the paper. Since I've got a decent base with the X/Y coordinates - I'm hoping to apply some of the calculations found in LCD libraries for drawing lines and curves - should be pretty simple to apply the same logic. spirilis, roadrunner84, Rei Vilo and 3 others 6 Quote Link to post Share on other sites
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