Is it something in the water, or have there been a lot of really cool servo projects lately? Mechaduino is a board that sits on a regular stepper motor and turns it into a servo with a closed loop control of 0.1degree.

Whenever we post something about using cheap brushless motors for precision control, someone comments that a stepper is just a brushless motor with a lot of poles, why not just control it like one. That’s exactly what the Mechaduino does. They also hint at doing something very clever with a magnetic encoder on the board which allows them, after a calibration routine, to get the accuracy they’ve promised.

T
he Arduino-sounding bit of the name comes from their full compatibility with the Arduino development environment. The brains of the board is the compatible,  SAMD21 ARM M0+  chip. They wanted the board to be as accessible as possible. On top of this, it also allows the user to use any control algorithm they want for the board. Most industrial controllers are limited to PID control, for returning to the last sent position. Opening up the control allows for interesting applications, such as motors that behave like mass spring damper systems, or electronically gearing the input of one stepper to the output of another.

The board supports lots of standard communication protocols, but the acceptance of regular stepper inputs make it extra interesting. It can become a drop-in replacement for the motors on a normal CNC or 3D printer, which have full closed loop control as shown in the video after the break.

They intend to keep working on the project until it gets to a level where they could kickstart it. However, rather than vaguely promise an open source release sometime after the launch like some have done, interested readers can skim all the design files off their GitHub and get to playing with it today. Firmware and Hardware.

“String Art” is the name of the art form that transforms thousands of nails and just as many feet of thread into unique masterpieces. Some artists have developed techniques to create photorealistic string art works, but until now, there was no way around the tedious and time-consuming manufacturing process. Depending on the size, it can take months to complete a single piece by hand.

Now, you might think, wouldn’t it be great to build a sophisticated “nail and thread”-machine that takes care of the whole assembly process, from placing the nails on the board to winding the string around the nails? The people behind Laarco, a design studio in London, UK, did exactly that. Their project “Autograph” is effectively a large scale “printer” for string art, capable of satisfying the increasing demand for this form of image reproduction.

While they are not shy to show their amazing results, mostly string-art-converted photographs of celebrities, we will probably not get a full documentation on the hardware and software behind Autograph. After all, it took them four years of development to build this fully automated machine, and they are about to turn their string boss-ness into a strong business: You can now buy their unique string art pieces starting at $1,100.

Too expensive? Well, you can still build your own: The brain of the machine is a Raspberry Pi which sends commands to an Arduino Mega equipped with a 3D printer shield. The gantry design looks very similar to a popular low-cost CNC-mill, however, they added a custom tool head to position and uncoil the thread while keeping it under tension.

In preparation of an assembly pass, the nail positions are derived from Voronoi diagrams, an unknown mechanism then picks and places the nails into pre-drilled holes. During the threading run, the height of the tool head increases as the process progresses to avoid collisions with previous string segments.

We’ve seen drawing-bots, polar graphs and robotic artists in various forms in the past, but it’s probably safe to say that this is the first string art machine ever built. That said, enjoy the video:

Last November, after [HomoFaciens]’ garbage-can CNC build, we laid down the gauntlet – build a working CNC from cardboard and paperclips. And now, not only does OP deliver with a working CNC plotter, he also plans to develop it into a self-replicating machine.

To be honest, we made the challenge with tongue firmly planted in cheek. After all, how could corrugated cardboard ever make a sufficiently stiff structure for the frame of a CNC machine? [HomoFaciens] worked around this by using the much less compliant chipboard – probably closest to what we’d call matboard here in the States. His templates for the machine are extremely well thought-out; the main frame is a torsion box design, and the ways and slides are intricate affairs. Non-cardboard parts include threaded rod for the lead screws, servos modified for continuous rotation, an Arduino, and the aforementioned paperclips, which find use in the user interface, limit switches, and in the extremely clever encoders for each axis. The video below shows highlights of the build and the results.

True, the machine can only move a pen about, and the precision is nothing to brag about. But it works, and it’s perfectly capable of teaching all the basics of CNC builds to a beginner, which is a key design goal. And it’s well-positioned to move to the next level and become a machine that can replicate itself. We’ll be watching this one very closely.

[Neumi] has built a CNC Laser using CD-ROM drives as the X and Y motion platforms. The small 405nm laser can engrave light materials like wood and foam. The coolest use demonstrated in the video is exposing pre-coated photo-resist PCBs.

With $61 US Dollars (55 Euro) for the Arduino, stepper drivers, and a laser in the project, [Nuemi] got a pretty capable machine after adding a few parts from the junk bin. He wanted to avoid using existing software in order to learn the concepts behind a laser engraver. In the end, he has a working software package which can send raster scans to an Arduino mega. The mega then controls the sync between the stepper and laser firings. The code is available on GitHub.

The machine can do a 30x30mm PCB in 10 minutes. It’s not about to set a record, but it’s cool and not at all bad for the price. You can see the failed PCBs lined up in the video from the initial tuning, but the final one produced a board very equivalent to the toner transfer method. Video after the break.

Forget sourcing parts for your next project from some fancy neighborhood hardware store. If you really want to show your hacker chops, be like [HomoFaciens] and try a Dumpster dive for parts for a CNC machine build.

OK, we exaggerate a little – but only a little. Apart from the control electronics, almost everything in [HomoFacien]’s build could be found by the curb on bulk-waste pickup day. Particle board from a cast-off piece of flat-pack furniture, motors and gears from an old printer, and bits of steel strapping are all that’s needed for the frame of a serviceable CNC machine. This machine is even junkier than [HomoFacien]’s earlier build, which had a lot more store-bought parts. But the videos below show pretty impressive performance nonetheless.

Sure, this is a giant leap backwards for the state of the art in DIY CNC builds. but that’s the point – to show what can be accomplished with almost nothing, and that imagination and perseverance are more important for acceptable results than an expensive BOM.

With that in mind, we’re throwing down the gauntlet: can anyone build a CNC machine from cardboard and paperclips?

A vise, a hacksaw and file, some wrenches – the fanciest tools [HomoFaciens] uses while building his DIY hardware store CNC machine (YouTube link) are a drill press and some taps. And the bill of materials for this surprisingly precise build is similarly modest: the X- and Y-axes ride on cheap bearings that roll on steel tube stock and aluminum angles; drives are threaded rods with homemade encoders and powered by small brushed DC gear motors; and the base plate appears to be a scrap of ping-pong table. The whole thing is controlled by an Arduino and four H-bridges.

The first accuracy tests using a ball point pen for tooling are quite impressive. [HomoFaciens] was able to draw concentric circles eyeball-accurate to within a few tenths of a millimeter, and was able to show good repeatability in returning to a point from both directions on both the X- and Y-axis. After the pen tests, he shows off a couple of other hardware store tooling options for the Z-axis – a Proxxon rotary tool with a burr for engraving glass; a soldering iron for cutting styrofoam; and a mini-router that works well enough to cut some acrylic gears.

We’re impressed by this build, which demonstrates that you don’t need a fancy shop to build a CNC machine. If you’re getting the itch to jump into the shallow end of the CNC pool, check out some of the builds we’ve featured before, like this PVC CNC machine, or this $250 build.

[Thanks, ThunderSqueak]

We love shop made CNC mills, so when [joekutz] tipped us off about the desktop sized CNC he just completed, we had to take a look. Each axis slides around on ball bearing drawer slides, and the machine itself is constructed with MDF and aluminum. And the results it produces are fantastic.

The machine’s work area weighs in at 160*160mm with a height of 25mm. Its the table is moved around with a pair of NEMA17 motors and M8 stainless steel threaded rods. Motor control is done with a pair of Arduino’s but they also do double duty with one processing G-code while the other handles the keypad and LCD interface.

The business end is a Proxxon rotary tool whizzing up to 2000RPM, and while [joekutz] hasn’t tried it on soft metals like brass or aluminum, he has successfully cut and engraved wood, plastics and copper clad PCB material.

Be sure to join us after the break for some YouTube videos. [joe] has posted three of a planned five-part-series which aren’t linked to in the project page shown above. to see this machine in action and get a rundown how it all works

Rotary indexer’s are standard issue in most machine shops. These allow you to hold or chuck a work piece, and then a graduated handle lets you to rotate the workpiece. Useful when you want to drill or tap axial or radial features. A rack and pinion drive ensures that the workpiece does not move under machining load. Quite often, these indexers also have a manual lock to take care of gear backlash and play. Automating them is not too difficult either. You could use just a stepper motor (open loop) or servo+encoder (closed loop) to drive the turntable.

[smashedagainst] needed to drill six radial holes on a part. And he had to do it on 500 pieces for a total of 3000 holes. That was just for the first initial run, with more drilling likely in the future. The part in question was small and light weight. So instead of using a heavy duty, industrial grade unit, he built an all-electric rotary indexing jig using a stepper motor and an Arduino, giving him a sort of rotary 4th axis. His idea was to directly use the stepper motor to rotate the workpiece without any gearing, but he needed to build his own rig to do so.

His initial prototype used an Arduino Uno, which he swapped for a Pro Mini in the final version to save some space. The Arduino was connected to a Rugged Circuits motor driver. This was the only driver, out of the several that he tried that managed to hold the stepper motor with enough torque to prevent the workpiece from moving while drilling. The number of holes to be drilled is hard-coded in the Arduino, so all he needed was a single button. Each press of the button advanced the stepper motor through 60 degrees, giving him six, equally spaced holes. He used a NEMA-34 stepper motor, and that meant a beefy power supply. He scavenged a power supply from an old laser printer which conveniently had 24V DC as well as 5V outputs.

The next step was to work on the mechanical assembly. He machined an arbor that is attached to the shaft of the stepper motor. The face of the arbor is hexagonal and the workpiece wedges/locates over this. The motor assembly is fixed on one end of a base plate. The other end of the base plate has a clamping mechanism activated by a toggle clamp. It is also able to rotate (much like a live centre on a lathe). The workpiece is mated to the arbor, and the toggle clamp then locks the piece in place. During initial trials, some of the assembly fasteners worked loose, and there was some amount of chatter from the drill bit. He fixed these issues, and found it performed best when he set the spindle speed at 2400 rpm. Once he got it working, he was able to finish a hundred parts in under 2 hours. Drilling six holes in quick succession causes the part to get quite hot, so he first used some  pressurised air cooling. Later, he switched to a spray can based multi purpose penetrant lubricant. Watch his video of the indexing jig in action below.

[Vegard] and his wife were expecting a baby girl, and decided to build a castle for their new daughter. As a prototyping geek with his own CNC machine in his apartment, he decided to take to Google Sketchup to design this well-crafted castle decoration for his daughter’s room.

The first challenge was figuring out what the castle would look like. [Vegard] had never been to Disney Land or World, and so had never actually seen any of the fairy-tale castles in real life. After experimenting with some paper versions, he settled on a design which incorporates multiple layers and can house lights within them.

The next step was to cut the final version on the CNC machine, then sand and paint the parts. After figuring out a way to mount the castle to the wall, some LEDs were added for effect, driven by an Arduino. The final version looks pretty good!

Hacking your kids’ room is great fun, and you get to keep making new stuff to remain age appropriate. We bet [Vegard] can’t wait until she’s old enough to enjoy a marble-run that wraps the entire room. In the mean time he can work on a classic robot stroller.

Children of the information age are doomed to have the worst handwriting just for lack of use if nothing more. But some students at Olin College harnessed technology to find a solution to that problem. Meet Herald, a CNC machine that can produce beautiful calligraphy.

The machine uses a gantry to move the writing tip along the X and Y axes. The flexible-nib calligraphy pen is mounted on a sprocket which rotates the tip onto the writing surface, taking care of the third axis. The rig was beautifully rendered from their CAD drawings, then tweaked to ensure the smoothest motion possible before the quintet of Sophomores began the physical build.

The drive hardware is very simple yet it produces great results. It uses an Arduino along with three stepper motor drivers. There are also limiting switches to protect the hardware from runaway code. The software interface designed by the team lets the user cut and paste their text, and select a font, font size, alignment, etc. It then converts the text to G-code and pushes it to the Arduino where the GRBL package takes care of business.

Don’t miss the device in action, writing out a [Langston Hughes] work in the clip after the break.