Optical Data Transfer Project At Local School’s Family Science Night

February 28, 2013 by Mike Szczys 9 Comments

optical-data-at-family-science-night

[Dave] wanted to show off a project at his 4th-grade son’s school during their family science night. We haven’t heard of an event like this before but it sounds like a fabulous idea! He had a new laser he wanted to include in the project, and noticed that his son was learning about how ASCII maps letters to binary number when the idea struck. He ended up building an optical data transfer system that demonstrates binary code.

This presents a fantastic learning opportunity as the project invited the school kids to select encoded strips like the ones seen above to form a secret message. The laser is pointed at a photosensor which is being read by a Raspberry Pi board. The Python code looks for a baseline and then records increases and decreases in intensity. Since the translucent tokens have either holes or black lines for 0 and 1 the baseline approach does away with the need to clock in the data. [Dave] reports that everyone who tried out the experiment was fully engaged at the prospect of pushing pieces of tape through the sensor and watching their secret message appear on a monitor.

He was motivated to write about this project after reading about data transfer using an LCD screen and photosensor.

Laser Kaleidoscope Uses More 3D Printing And Less Scavenging

February 25, 2013 by Mike Szczys 6 Comments

laser-kaleidoscope

At first we thought that [Pete Prodoehl] was using the wrong term when calling his project a Laser Kaleidoscope. We usually think of a kaleidoscope as a long tube with three mirrors and some beads or glass shards in one end. But we looked it up and there’s a second definition that means a constantly changing pattern. This fits the bill. Just like the laser Spirograph from last week, it makes fancy patterns using spinning mirrors. But [Pete] went with several 3D printed parts rather than repurposing PC fans.

In the foreground you can see the potentiometers which adjust the motor speeds. The knobs for these were all 3D printed. He also printed the mounting brackets for the three motors and the laser diode. A third set of printed parts makes mounting the round mirrors on the motor shaft quite easy. All of this came together with very tight tolerances as shown by the advanced shapes he manages to produce in the video after the break. Continue reading “Laser Kaleidoscope Uses More 3D Printing And Less Scavenging” →

Laser Spirograph

February 21, 2013 by Mike Szczys 11 Comments

laser-spirograph

Here’s a weekend junk bin project if we’ve ever seen one. [Pat] used a quartet of computer fans to make his laser Spirograph. Deciding to try this simple build for yourself will run you through a lot of basics when it comes to interfacing hardware with a microcontroller. In this case it’s the Arduino Nano.

The Spirograph works by bouncing a laser off of mirrors which are attached to the PC fans. When the fans spin the slight alignment changes cause the laser dot to bob and weave in visually pleasing ways. You can catch twenty minutes of the light show in the clip after the break.

Three of the fans have mirrors attached, the housing of the fourth is used to host the laser diode and make assembly easier. A TC4469 motor driver is used to connect the fans to the Arduino. The light show can be manually controlled by turning the trio of potentiometers which are read using the Arduino’s ADC.

If you manage your way through this build perhaps you’ll move on to a setup that throws laser light all over the room.

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3D Scanner Made In A Day

February 14, 2013 by Mike Szczys 12 Comments

diy-3d-scanner

The LVL1 Hackerspace held a hackathon back in June and this is one of the projects that was created in that 24-hour period. It’s a 3D scanner made from leftover parts. The image gives you an idea of the math used in the image processing. It shows the angular relations between the laser diode, the subject being scanned, and the webcam doing the scanning.

The webcam is of rather low quality and one way to quickly improve the output would be to replace it with a better one. But because the rules said they had to use only materials from the parts bin it worked out just fine. The other issue that came into play was the there were no LCD monitors available for use in the project. Because of that they decided to make the device controllable over the network. On the right you can see a power supply taped to the top of a car computer. It connects to the laser (pulled out of a barcode scanner which produces a line of red light) and the turntable. A Python script does all of the image processing, assembling each slice of the scan into both an animated GIF and an OBJ file.

[Thanks Nathan]

One Method Of Fabricating Translucent Faceplates

January 16, 2013 by Mike Szczys 41 Comments

laser-cut-translucent-panel-covers

Enclosures are the bane of electronics engineers (or so says [Dave Jones] of the EEVblog and The Amp Hour). But fabricating a case that looks great has been getting easier lately. [Eric Forkosh] produced this professional-looking translucent face plate with a minimum of effort. He found a way to use a laser cutter to etch icons in acrylic.

Admittedly, this is not very involved. But just look at the quality he achieved. The secret to his success (aside from having a quality laser cutter on hand) is to use high-temperature spray paint. The acrylic is coated in paint and allowed to dry before heading to the laser cutter. By using the rasterize setting under low power he kills two birds with one stone; the paint is etched away while the acrylic is left a little bit rough to act as a diffuser for LEDs behind the panel. [Eric] cautions against using regular spray paint. In his write up he shows off the unsightly results of doing so.

This makes a great addition to some of the case options out there. One that we have been keeping our eye on is the Sick of Beige initiative being spearheaded by [Ian Lesnet].

More Details About Laser Cut Gingerbread Houses

December 17, 2012 by Mike Szczys 18 Comments

Members of Sector67 tried their hands at laser cut gingerbread houses. The Madison, Wisconsin based hackerspace is using the tabbed box method of assembly for the corners of the structure. They’ve also put up a bunch of information about laser settings and published the recipe used to mix up a sheet of gingerbread. This quite a bit more info than was provided with the project we saw a couple of weeks back.

The initial designs were made in Inkscape and then transferred to Corel Draw before heading to the cutter. They’ve got a 150W machine and found that a speed of 15 worked well when the speed was set to 100, with a corner speed of 60. The raw dough was rolled out to 1/8″ thickness. Possibly the best tip coming out of Sector67 is to lay 1/8″ dowels on either side of the dough. This way the rolling pin will stop when it hits the dowels resulting in the best possible uniform thickness. As reported in the previous project the odor generated while cutting is not the most pleasant. But we love the fusion of lasers with the age old process of building with cookies and decorating with candy.

Converting A Chinese Laser Cutter To Work With Mach3

December 13, 2012 by Brian Benchoff 38 Comments

laser

Like most of us, [Chris] has pined over the very, very inexpensive Chinese laser cutters available on eBay for a while now. When most of us disregarded these machines due to their inability to work with the file formats commonly used with laser cutters, [Chris] took the plunge. He was a might disappointed the included software didn’t allow him to use his machine with Mach3 CNC software, so he replaced the included electronics board with one of his own design, giving him all the features of a more expensive laser cutter at a low, low Chinese eBay auction price.

The laser cutter [Chris] bought came with the moshidraw software and controller board that according to one auction can only use BMP, JPEG, WMF, EMF, and PLT files.Wanting a board that can use more common file formats such as PDF and DWG, [Chris] built his own board to communicate with his Mach3 software.

From what we can tell, the new board works with off-the-shelf Pololu stepper drivers and is a complete drop in replacement for the moshidraw board. He’s still finalizing the design, but when the layout, BOM, and schematic are finalized, [Chris] will be putting the files up for everyone to copy. Wonderful piece of work, [Chris].

Continue reading “Converting A Chinese Laser Cutter To Work With Mach3” →