Laser Diode Controller For A CNC Mill

August 15, 2012 by Mike Szczys 16 Comments

[Smells of Bikes] wanted to add laser etching to the list of tricks his home CNC setup is capable of. He has a diode which will work for the task, but he needed a driver that could be interfaced with the CNC system. He ended up designing a driver board based around the LM3402 chip.

Now driving one of these laser diodes isn’t all that different from driving a Light Emitting Diode. He chose to use the LM3402 chip because he’s the TI engineer who designed the official evaluation board for the part. It’s meant for high-power LED applications, and the 700 mA he needs for the laser is within spec. Since he’s soldering by hand, and this part has a ground pad on the bottom, he shares his soldering technique in detail. Once the driver board is ready, he uses a ‘sed’ command to replace the g-code Z axis commands with digital on/off commands to switch the diode.

Check out the demo video after the break. He uses a diffuse beam since the cutting beam is bright enough to damage his camera.

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Copper Vapor Laser Is Amazing

August 13, 2012 by Brian Benchoff 25 Comments

What better way to spend a few months in the workshop than by heating Copper chloride to 400° C, building rotary spark gaps and 30kV capacitors, playing with high vacuums and building a very powerful laser? It’s just a day in [Jon]’s life as he builds a DIY Copper vapor laser.

Copper vapor lasers require temperatures of about 1500° C, but this is only when using pure Copper. Compounds such as Copper chloride are able to bring the required temperatures for lasing down to about 400° C, a reasonable temperature for [Jon]’s home built laser tube furnace. The only problem with this setup is the requirement for two electrical pulses, one to disassociate the Copper and a second to make the Copper lase.

The professional way of creating these electrical pulses would be a Thyratron, but it seems [Jon] wanted something cooler. He built a rotary spark gap out of two 2 inch thick blocks of acrylic that allow him to perfectly time the frequency and separation of the electrical pulses needed for his laser.

There is no word on exactly how much power [Jon]’s Copper vapor laser will put out when it’s complete, but [Jon]’s build log is already an amazing display of awesome. You can check out a short video showing off [Jon]’s laser, spark gap, and huge home-made capacitor after the break.

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Exposing PCBs With A Home Made Laser Printer

August 9, 2012 by Brian Benchoff 50 Comments

Making your own printed circuit boards – as useful as it is – is a pain. Using the very popular toner transfer method requires a dozen steps that have to go perfectly the first time, and milling boards on a CNC machine creates a lot of mess. The most industrious hackers are able to bodge up a direct-to-board printer from an old inkjet printer, but these builds are usually a little kludgy. [Tixiv]’s LaserExposer board printer is one of the first builds we’ve seen that does away with all the negatives of the other techniques of PCB manufacturing and turns making your own boards into a very, very simple process.

The LaserExposer uses photosensitive copper board, like many of the other PCB printers we’ve seen. Instead of printing out the board artwork to a transparency or mask, [Tixiv] used a 1 Watt 445nm blue laser with a hexagonal mirror to directly expose the artwork onto the board, line by line.

The entire device is built around an old flatbed scanner that slowly crawls over the PCB, exposing the traces of copper to be etched away. This required reverse engineering the mirror motor control board from an 90s-era laser printer and building a circuit to precisely control the timing of the laser. [Tixiv] eventually got everything working and after etching had some of the most professional looking home-brew boards we’ve ever seen.

[Tixiv] put up a demo video of his build (after the break, German audio, YouTube has captions…). Anyone have an old flatbed scanner lying around?

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Displaying Tweets With A Laser Pointer And Speakers

August 1, 2012 by Brian Benchoff 15 Comments

This year at Toorcamp, [Rich] will be showing off his laser-based vector display, capable of projecting tweets using only a laser pointer, a pair of mirrors, speakers, and an Arduino. Steady hand and curses from lack of an optical bench not included.

[Rich]’s Instructable goes over the finer points of the build; a Python script runs on his computer fetching all recent tweets with a certain hashtag. These tweets are sent over to a ‘duino where a bit of code translates the text into a scrolling vector display. The code for the project is based on one of [Rich]’s previous builds to draw shapes with the same speaker/laser setup.

In theory, using a pair of speakers to draw text on a wall isn’t much different from drawing pictures on an oscilloscope. Of course, [Rich] always has the option of turning his LaserTweet into an oscilloscope when Toorcamp is over.

Relevant videos after the break.

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Laser Light Painting Includes Camera Control

July 13, 2012 by Mike Szczys 6 Comments

This laser light painting setup can even control the camera. But it probably will not work with your average point-and-shoot. The exposure time used is somewhere around 2 seconds long, a feature which is hard to find on anything but DSLR cameras.

The setup relies on a red laser diode to do the painting. When viewed in real time you only see a dot tracing out a cryptic pattern and occasionally switching on and off. But with a long exposure the intense light persists to achieve an image like the one seen above. Note the ghosting around the rig as it has moved while the shutter was open.

The Arduino controlled device consists of a base which pivots the diode horizontally, with a servo for aiming on the vertical axis. Since the sketch is divided up by letter, we wonder how hard it would be to adapt this for use with a point-and-shoot? Perhaps you could capture one letter at a time and layer the frames in post production?

It seems this is a lot easier to build than some of the LED plotters we’ve looked at. If you do make your own don’t forget to send a link our way.

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Laser-charged Glow In The Dark Message Board

July 10, 2012 by Mike Szczys 3 Comments

This entry in the Red Bull Creation contest uses a laser to charge up a glow-in-the-dark message board. The concept is something we’ve seen several times before. Since light can excite a phosphorescent surface, moving pixels of light over that surface leaves a fading trail. Most recently we saw a spinning ring message board. This contest entry is different in that the board is stationary and the print head moves.

It’s basically a two-wheeled robot with a laser diode which can swivel perpendicular to the direction of travel. In this way, the laser prints the rows, and the motion of the robot takes care of advancing the columns. Since laser light has incredible intensity it is able to excite the phosphors much more thoroughly than LEDs. So the message will last longer than that spinning ring project or this awesome turntable hack. Don’t miss the video after the break that shows off the hack along with a bag full of theatrics.

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Hoisting A Laser Cutter To The 3rd Floor (and Other Fun You’ll Probably Never Have)

June 19, 2012 by Mike Szczys 36 Comments

The folks at Null Space Labs bought a 40W CO2 laser tube in order to build their own laser cutter. Unfortunately nobody really wants to build a laser cutter; they just want to play with a laser cutter. So they ended up biting the bullet and ordering a $4000 model from China. That’s it hovering in midair. This is the story of acquiring the unit and playing around with it once it arrived.

Check out those orange cones in the picture. Hackerspace members put them out to keep the parking spots clear so no damage was caused in the event of an accident. But since they’re located in Los Angeles some of the road warriors didn’t really care and just moved the cones anyway. Luckily the crane hoist to the third floor (they removed one of the windows) ended up going rather well.

So what do you do with a laser cutter like this one? Crack it open and make some improvements. The manufacturer says it can’t cut through steel. Well that’s only if you don’t add some O2 to the cutting process. And the stock mirrors… they’ve got to go. Turns out a simple upgrade boosted the power by about 20% (we’re wondering how they measured that). While we’re talking about optics, might as well upgrade the lens as well. You can see where they’re going with this, and [CharlieX] tells us it is just the first in a series of posts he’ll be working on.