Afroman Teaches Intro To Servos, Builds Laser Turret

January 7, 2018 by Kristina Panos 10 Comments

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.

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Monoprice Mini Laser Engraver Hack

December 26, 2017 by Al Williams 12 Comments

There’s an old saying, that in theory there’s no difference between theory and practice, but in practice there is. That sentiment could easily be applied to refitting a 3D printer to hold a laser. There shouldn’t be much to it, rig up a laser module to turn on under computer control, mount it to your hot end carriage and off you go. In practice, though there are other considerations to account for. If you have a Monoprice Mini Select, you can start with instructions from [drodrii] for adding a laser to your printer.

Although [drodrii] mentions that you need a second 3D printer to make a bracket for the laser, we think you should be able to print it on the Mini as long as you do it before the first step of removing the hot end. However, since your laser module might not exactly match the one used in this project, you’d have to get it right the first time if you don’t have another 3D printer. Of course, you could remove the laser gear, remount the hot end, print a new bracket and start over, but that’d be a drag.

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Improving Cheap Laser Engravers For PCB Fabrication

December 22, 2017 by Brian Benchoff 24 Comments

A few months ago, [Marco] picked up a cheap, cheap, cheap laser engraver from one of the familiar Chinese resellers. It’s a simple affair with aluminum extrusions, a diode laser, and a control board that seems like it was taken from a 3D printer controller designed five years ago. Now, [Marko] is building some upgrades for this engraver and his PCB production skills have gone through the roof.

The laser engraver [Marko] picked up is called the EleksMaker, and lucky for him there are quite a few upgrades available on Thingiverse. He found two 3D printable parts, one that keeps the belt parallel to the aluminum extrusion, and another that provides adjustable x-axis tightness on the belt. With these two mods combined, [Marko] actually has a nice, smooth motion platform that’s more precise and makes better engravings.

These upgrades weren’t all 3D-printable; [Marko] also got his hands on a few Trinamic TMC2130 stepper motor drivers. These stepper drivers are the new hotness in 3D printing and other desktop CNC machines, and looking at the waveform in an oscilloscope, it’s easy to see why. These drivers produce a perfectly smooth waveform via interpreted microstepping, and they’re almost silent in operation. That’s terrible if you want to build a CNC chiptune player, but great if you want smooth engraving on a piece of copper clad board.

This project has come a long way since the last time we took a look at it a few months ago, and the results just keep getting better. [Marko] is making real PCBs with a laser engraver that cost less than $200, and the upgrades he’s already put into it don’t add up to much, either. You can take a look at [Marko]’s progress in the video below.

Thanks [dechemist] for the tip.

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Home-Brew Ruby Laser Packs A Wallop

December 19, 2017 by Dan Maloney 31 Comments

In the past half-century, lasers have gone from expensive physics experiments using rods of ruby to cheap cutting or engraving tools, and toys used to tease cats. Advances in physics made it all possible, but it turns out that ruby lasers are still a lot of fun to play with, if you can do it without killing yourself.

With a setup that looks like something from a mad scientist movie set, [styropyro]’s high-powered laser is a lot closer to the ray gun of science fiction than the usual lasers we see, though hardly portable. The business end of the rig is a large ruby rod nestled inside a coiled xenon flash lamp, which in turn is contained within a polished reflector. The power supply for the lamp is massive — microwave oven transformers, a huge voltage multiplier, and a bank of capacitors that he says can store 20 kilojoules. When triggered by a high-voltage pulse from a 555 oscillator and an old car ignition coil, the laser outputs a powerful pulse of light, which [styropyro] uses to dramatic effect, including destroying his own optics. We’d love to hear more about the power supply design; that Cockcroft-Walton multiplier made from PVC tubes bears some exploration.

Whatever the details, the build is pretty impressive, but we do urge a few simple safety precautions. Perhaps a look at [Ben Krasnow]’s 8-kJ ruby laser would help.

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Poor Man’s Laser Scanner Probably Won’t Shoot Your Eye Out, Kid

December 16, 2017 by Dan Maloney 13 Comments

Yes, laser cutters that come off the slow boat from China are more affordable than ever, and with some tweaks and hacks they can turn out some decent results. But if you just want a laser lightshow that’ll draw boxes on your living room ceiling, this simple X-Y laser scanner might be a good platform to build.

Let’s say right up front that there are more than a few safety issues with [ThingEngineer]’s 3D-printed two-axis scanner. He’s well aware of these potential retina-cooking issues and duly notes that a good pair of laser safety goggles is a must and that the cheap anti-lawsuit glasses that laser module manufacturers often include with their products don’t count.

[Editor’s Note: Glasses are really only intended for alignment operations. Pros enclose lasers beyond a certain power to prevent anyone going blind. Know where your beam terminates, kids.]

With that in mind, there’s a lot to be said for this poor man’s scanner build. Yes, it would be faster with real galvos and low-mass mirrors, but time is money, and the steppers and craft store mirror discs do the job, albeit slowly. We like that everything is so simple, even the method for turning a regular mirror into a front-surface mirror.

[ThingEngineer] proves you don’t need galvanometers to have some simple laser fun. And if steppers don’t do it for you, you can try little brushed DC hobby motors or even 3D-printed cams.

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Better 3D Printing Through Holography

December 16, 2017 by Al Williams 22 Comments

When most of us think about 3D printing, we usually think about a machine that melts plastic filament and extrudes it through a nozzle. But we all know that there are other technologies out there that range from cutting and laminating paper, to printing with molten metal or glass. Many of those are out of range for the common hacker. Probably the second most common method uses photo resin and some light source to build the layers in the resin. Researchers at Lawrence Livermore National Laboratory (LLNL) and several universities are experimenting with a new technique that exposes photo resin using three lasers, printing an entire object at one time. You can see a cube formed using the technique in the video below.

In all fairness, the process really isn’t holography but LLNL refers to it as “hologram-like.” In fact, it appears the lasers project more like an oblique projection (you know, like in drafting) which is considerably simpler. Simple enough, that we can’t help but wonder if the hacker community couldn’t develop machines based on this principle. The key would be arranging for the resin to only cure where laser light overlaps.

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MIT Is Building A Better 3D Printer

December 9, 2017 by Tom Nardi 79 Comments

Traditional desktop 3D printing technology has effectively hit a wall. The line between a $200 and a $1000 printer is blurrier now than ever before, and there’s a fairly prevalent argument in the community that you’d be better off upgrading two cheap printers and pocketing the change than buying a single high-end printer if the final results are going to be so similar.

The reason for this is simple: physics. Current printers have essentially hit the limits of how fast the gantry can move, how fast plastic filament can pushed through the extruder, and how fast that plastic can be melted. To move forward, we’re going to need to come up with something altogether different. Recently a team from MIT has taken the first steps down that path by unveiling a fundamental rethinking of 3D printing that specifically addresses the issues currently holding all our machines back, with a claimed 10-fold increase in performance over traditional printing methods.

MIT’s revolutionary laser-assisted hot end.

As anyone who’s pushed their 3D printer a bit too hard can tell you, the first thing that usually happens is the extruder begins to slip and grind the filament down. As the filament is ground down it starts depositing plastic on the hobbed gear, further reducing grip in the extruder and ultimately leading to under-extrusion or a complete print failure. To address this issue, MIT’s printer completely does away with the “pinch wheel” extruder design and replaces it with a screw mechanism that pulls special threaded filament down into the hot end. The vastly increased surface area between the filament and the extruder allows for much higher extrusion pressure.

An improved extruder doesn’t do any good if you can’t melt the incoming plastic fast enough to keep up with it, and to that end MIT has pulled out the really big guns. Between the extruder and traditional heater block, the filament passes through a gold-lined optical cavity where it is blasted with a pulse modulated 50 W laser. By closely matching the laser wavelength to the optical properties of the plastic, the beam is able to penetrate the filament and evenly bring it up to nearly the melting point. All without physically touching the filament and incurring frictional losses.

There are still technical challenges to face, but this research may well represent the shape of things to come for high-end printers. In other words, don’t expect a drop-in laser hot end replacement for your $200 printer anytime soon; the line is about to get blurry again.

Speeding up 3D printing is a popular topic lately, and for good reason. While 3D printing is still a long way off from challenging traditional manufacturing in most cases, it’s an outstanding tool for use during development and prototyping. The faster you can print, the faster you can iterate your design.

Thanks to [Maave] for the tip.

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