Posts with «laser hacks» label

Afroman Teaches Intro to Servos, Builds Laser Turret

After a longish hiatus, we were pleased to see a new video from [Afroman], one of the most accessible and well-spoken teachers the internet has to offer. If you’re new to electronics, see the previous sentence and resolve to check out his excellent videos. The new one is all about servos, and it culminates in a simple build that provides a foundation for exploring robotics.

[Afroman] leaves no gear unturned in his tour de servo, which is embedded after the break. He explains the differences between open vs. closed loop motor systems, discusses the different sizes and types of servos available, and walks through the horns and pigtails of using them in projects. Finally, he puts this knowledge to use by building a laser turret based on a pan-tilt platform.

The Arduino-driven turret uses two micro servos controlled with pots to move by degrees in X/Y space. Interestingly, [Afroman] doesn’t program the board in the Arduino IDE using wiring. Instead, he uses an open-source microcontroller language/IDE called XOD that lets you code by building a smart sort of schematic from drag-and-drop components and logic nodes. Draw the connections, assign your I/O pin numbers, and XOD will compile the code and upload it directly to the board.

XOD seems like a good tool for beginners to do rapid prototyping. On the other hand, a look into the generated code reveals a whole lot of wrappers that obfuscate the bits of code that actually do stuff. There doesn’t seem to be a way to shed them, either, so once you design something in XOD, you’re kind of stuck using it to iterate. That said, the generated code is well documented, and someone who knows what they’re looking at could find, for instance, the I/O pin assigned to the blink sketch LED.

Once the novelty of the double laser cat tormentor has subsided, use the other servos in that 5-pack you bought to flip a light switch, control a knob, or play the glockenspiel.

Filed under: how-to, Laser Hacks

Laser Cutter Alignment Mod Skips Beam Combiner

A lot of the DIY laser engravers and cutters we cover here on Hackaday are made with laser diodes salvaged from Blu-ray drives and projectors, which are visible lasers in the 400 – 450nm range (appearing as violet or blue). Unfortunately there is an upper limit in terms of power on visible diode lasers, most builds max out at 5W or so. If you need more power than that, you’ll likely find yourself looking at gas laser cutters like the K40. While the K40 is a great starting point if you’re looking to get into “real” lasers, it’s a very different beast from the homebrew builds using visible lasers.

With a gas laser the beam itself is invisible, making it much more difficult to align or do test runs. One solution is to add a visible laser to the K40 which can be used to verify alignment, but making sure it’s traveling down the same path as the primary laser usually requires an expensive beam combiner. Looking to avoid this cost, [gafu] wanted to see if it was possible to simply move the visible laser into the path of the primary beam mechanically.

An adjustable microswitch detects when the lid has been opened.

In the setup that [gafu] has come up with, a cheap laser module (the type from a handheld laser pointer) is moved into the path of the primary laser on an arm that’s actuated by a simple hobby servo. To prevent the primary and visible lasers from firing at the same time, an Arduino is used to control the servo given the current state of the K40’s lid. If the lid of the K40 is open, the primary laser is shutoff and the visible laser is rotated into position so the operator can see where the primary laser’s beam would be hitting. Once the lid is closed, the visible laser rotates out of the way and the primary is powered back up.

Running the cutting or engraving job with the lid of the K40 machine open now let’s [gafu] watch a “dry run” of the entire operation with the visible laser before finally committing to blasting the target with the full power beam.

We’ve covered many hacks and modifications for everyone’s favorite entry-level CO2 laser cutter. From replacing the controller to making it bigger, K40 owners certainly seem like a creative bunch.

Filed under: Arduino Hacks, hardware, Laser Hacks

Speakers Make a LASER Scanning Microscope

We’ve seen a lot of interest in LSM (LASER Scanning Microscopes) lately. [Stoppi71] uses an Arduino, a CD drive, and–of all things–two speakers in his build. The speakers are used to move the sample by very small amounts.

The speakers create motion in the X and Y axis depending on the voltage fed to them via a digital analog converter. [Stoppi71] claims this technique can produce motion in the micron range. His results seem to prove that out. You can see a video about the device, below.

Oddly enough, [Stoppi71] found that older CD drives were easier to work with because they were not as miniaturized as more modern versions. The device uses the Arduino to drive the scanning table (the speakers), and read the photodetector. The results of the scan appear on an LCD screen.

Using a calibration slide from eBay, [Stoppi71] calibrated the device for different magnifications. You can see the test slide at medium magnification. For the record, a human hair is about 40 or 50 microns thick. So the 10 micron mark in the photo would be like splitting a hair in quarters or fifths.

The real goal was to view pits on CDs, and the instrument is more than capable of doing that. The image doesn’t show up all at once (it is scanning, after all) and it isn’t the kind of view you’d expect from an optical microscope, but a typical optical scope can’t resolve below about 200 microns. Special techniques can push that lower, but being able to resolve things at the one or two micron level with something this simple is a great accomplishment.

We recently saw a different-looking LSM built on a conventional microscope stage and a DVD drive. If LSM isn’t enough for you, maybe you should pitch in on the open source electron microscope project.

Filed under: laser hacks

Cheap Dual Mirror Laser Projector

[Stanley] wanted to make a laser projector but all he could find online were one’s using expensive galvanometer scanners. So instead he came up with his own solution that is to be admired for its simplicity and its adaptation of what he could find.

At its heart is an Arduino Uno and an Adafruit Motor Shield v2. The green laser is turned on and off by the Arduino through a transistor. But the part that makes this really a fun machine to watch at work are the two stepper motors and two mirrors that reflect the laser in the X and Y directions. The mirrors are rectangles cut from a hard disk platter, which if you’ve ever seen one, is very reflective. The servos tilt the mirrors at high speed, fast enough to make the resulting projection on the wall appear almost a solid shape, depending on the image.

He’s even written a Windows application (in C#) for remotely controlling the projector through bluetooth. From its interface you can select from around sixteen predefined shapes, including a what looks like a cat head, a heart, a person and various geometric objects and line configurations.

There is a sort of curving of the lines wherever the image consists of two lines forming an angle, as if the steppers are having trouble with momentum, but that’s probably to be expected given that they’re steppers controlling relatively large mirrors. Or maybe it’s due to twist in the connection between motor shaft and mirror? Check out the video after the break and let us know what you think.

The video’s in three parts: looking at the laser beams in action as you’d see them on a dance floor, then watching the projected images while looking at an insert of the Windows application, and then watching the steppers and mirror doing their rapid movements.

As for the expensive galvanometer scanners we mentioned above, check out this impressive laser projector that uses them. Another method is to use a spinning wheel with mirrors set to different angles, like this one that draws a marquee using a pill box as the wheel. And how about one with no mirrors at all, instead attaching the laser directly to servo motors, though that one does take longer to draw.


Filed under: laser hacks

A Laser Effect Projector Built with Safety in Mind

There’s just something about wielding a laser pointer on a dark, foggy night. Watching the beam cut through the mist is fun – makes you feel a little Jedi-esque. If you can’t get enough of lasers and mist, you might want to check out this DIY “laser sky” effect projector.

The laser sky effect will probably remind you of other sci-fi movies – think of the “egg scene” from Alien. The effect is achieved by sweeping a laser beam in a plane through swirling smoke or mist. The laser highlights a cross section of the otherwise hidden air currents and makes for some trippy displays. The working principle of [Chris Guichet]’s projector is simplicity itself – an octagonal mirror spun by an old brushless fan motor and a laser pointer. But after a quick proof of concept build, he added the extras that took this from prototype to product. The little laser pointer was replaced with a 200mW laser module, the hexagonal mirror mount and case were 3D printed, and the mirrors were painstakingly aligned so the laser sweeps out a plane. An Arduino was added to control the motor and provide safety interlocks to make sure the laser fires only when the mirror is up to speed. The effect of the deep ruby red laser cutting through smoke is mesmerizing.

If laser sky is a little too one-dimensional for you, expand into two dimensions with this vector laser projector, and if monochrome isn’t your thing try an RGB vector projector.

Filed under: Arduino Hacks, laser hacks

UV Laser Projector Shines With Glow-in-the-Dark Vinyl

Mirror galvanometers were originally developed in the 17th century to precisely measure very small changes in current. Unlike other instruments of the day, a mirror galvanometer could clearly show minute current variations by translating tiny movements of the mirror into large movements of the light reflected off of the mirror. Before clean electrical amplification became possible, this was the best means of measuring tiny differences in current. True mirror galvanometers are very sensitive instruments, but hobby servos can be used as a low-fidelity alternative, like with this project on created by [robives].

Using a mirror galvanometer is by far the most common technique for laser projection shows – it’s really the only way to move the laser’s beam quickly enough to create the visual illusion of a solid line in real time. A mirror galvanometer works by using coils to attract magnets attached to the mirror, allowing the angle of the mirror to change when current is applied to the coils. This movement is extremely small, but is amplified by the distance to the projection surface, meaning the laser’s beam can move huge distances in an instance. If you’ve ever seen a laser show, it almost certainly used this technique. But driving galvos requires a beefy DAC, so we can’t blame [robives] for wanting to keep it digital.

[robives’s] project side-steps the need for galvanometers by using glow-in-the-dark vinyl and a UV laser. The result is a laser beam trail which lasts much longer, which means that solid lines are visible without the need for high-speed galvos. A build like this lets you experiment with laser projections without dealing with sensitive mirror galvos, and instead use components that you probably already have sitting on your workbench.

Filed under: laser hacks
Hack a Day 02 Dec 03:00

Pew Pew! An Arduino Based Laser Rangefinder

Lasers are some of the coolest devices around. We can use them to cut things, create laser light shows, and also as a rangefinder.[Ignas] wrote in to tell us about [Berryjam's] AMAZING write-up on creating an Arduino based laser rangefinder. This post is definitely worth reading.

Inspired by a Arduino based LIDAR system, [Berryjam] decided that he wanted to successfully use an affordable Open Source Laser RangeFinder (OSLRF-01) from LightWare. The article starts off by going over the basics of how to measure distance with a laser based system. You measure the time between an outgoing laser pulse and the reflected return pulse; this time directly relates to the distance of the object. Sounds simple? In practice, it is not as simple as it may seem. [Berryjam] has done a great job doing some real world testing of this device, with nice plots to top it all off. After fiddling with the threshold and some other aspects of the code, the resulting accuracy is quite good.

Recently, we have seen more projects utilizing lasers for range-finding, including LIDAR projects. It is very exciting to see such high-end sensors making their way into the maker/hacker realm. If you have a related laser project, be sure to let us know!

Filed under: laser hacks

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.

Filed under: laser hacks
Hack a Day 21 Feb 22:01

3D scanner made in a day

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]

Filed under: laser hacks

16×8 pixel laser projector

[Michiel] gave us a little shout-out by drawing the Hackaday logo with his recently completed 16×8 pixel laser projector. It uses a spinning set of mirrors mounted at slightly different angles to redirect the path of the red laser diode.

The projector is driven by an Arduino. To give it more than just a hard-coded existence [Michiel] included an Xbee module. This lets him connect to it with a computer in order to stream messages. One of the demo videos linked in his project log shows the web interface he coded which will push a message typed in the submission form out to the projector where it is scrolled like a marquee.

This type of spinning display is one of a few common methods for making laser projectors. In the image above you can see the optical sensor which is used to sync the diode with the spinning mirrors, each of which is responsible for a different row of pixels. He lists off several things that he learned when working on the project. We think the most important is the timing issues which go into something like this.

Filed under: laser hacks
Hack a Day 14 Sep 23:01