The Almost Useful Machine

June 11, 2016 by Kristina Panos 26 Comments

[Alex] is no stranger to making machines of negligible utility. A few years ago he made the Almost Useless Machine, a solar-powered system that cuts through a 20mm dowel rod while you wait (and wait, and wait). Enamored by the internet’s bevy of powered hacksaws, he sought to build a sturdier version that’s a little more useful. Approximately five months of free time later, he had the Almost Useful Machine.

It runs on a wiper motor and a recycled power supply from a notebook computer. [Alex] rolled his own board for controlling the motor with an ATtiny25. The circuit turns potentiometer movement into PWM, which controls the motor through a MOSFET. After the cut is finished, an endstop microswitch immediately cuts the motor.

Every bit of the chassis is aluminum that [Alex] machined by hand. Don’t have that kind of setup? How about a powered hacksaw with a 3D-printed linkage? Make the jump to see it in action, and stick around for the two-part time-lapse build video.

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New CNC Machine? DIY Machinable Wax!

June 11, 2016 by Jenny List 25 Comments

The folks at Leeds Hackspace have built themselves a shiny new C-beam based CNC mill. As you might expect everyone wants to try the machine out, but there’s a problem. A CNC machine presents a steep learning curve, and a lot of raw materials (not to mention cutting bits) can be used in a very short time. Their solution is simple: mix themselves some machinable wax from LDPE pellets and paraffin wax, then easily recycle their swarf and failed objects back into fresh machinable wax stock.

Making the wax recipe is not for the faint-hearted, and involves melting the LDPE pellets and wax to 130 degrees Celcius in a cheap deep-fat fryer. They bought the cheapest fryer they could find at the British catalogue retailer Argos, you really wouldn’t want to risk an appliance you cared about in this exercise.

Colouring came from an orange wax crayon, though they note recycling of mixed colours will inevitably result in a muddy brown. The finished mixture was poured into Tupperware lunchboxes to set, and the resulting blocks were trimmed to square on a bandsaw. The Tupperware proved not to have a flat bottom, so later batches were cast in a loaf tin which proved much more suitable.

We’ve mentioned the machinable wax recipe before here at Hackaday, but it’s worth returning to the topic here with a description of it being used in the wild. Having watched other environments get through learning materials at an alarming rate with very little to show for their effort, we can see it makes a lot of sense as a training material.

Pen-Plotter Firmware Written Completely In Ada

June 9, 2016 by Elliot Williams 43 Comments

[Fabian Chouteau] built a plotter out of CD-ROM parts. Yawn, you say? Besides being a beautiful physical build, this one has a twist. He wrote the software and firmware for the entire project himself, in Ada.

Ada is currently number two on our list of oddball programming languages that should be useful for embedded programming. It’s vaguely Pascal-y, but with some modern object-oriented twists. It was developed for safety-critical, real-time embedded systems (by the US Department of Defense), and is used in things like airplanes, rockets, and the French TGV trains. If that sounds like overkill for your projects, [Fabian]’s project shows that it’s still very tractable.

In his GitHub, he re-implements the GRBL G-code generator and then writes a GUI front-end for it. In his writeup, he mentions that the firmware and its simulator for the front-end use exactly the same code which is quite a nice trick, and guarantees no (firmware) surprises when moving from the modelled device to the real thing.

We looked quickly around for Ada resources and came up with: GNAT, the GNU Ada compiler, and its derivatives: GNAT for ARM (STM32-flavor), ARM-Ada (LPC21xx flavor), AVR-Ada, and MSP430-Ada.

Any of you out there use Ada in embedded work? We’d love to hear your thoughts.

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OpenPLC Is Ready For Hacking

June 7, 2016 by Gerrit Coetzee 48 Comments

It’s been nearly four years since we covered [Thiago]’s OpenPLC project. He never stopped working on it, and now it’s in a highly polished state.

If you read our initial coverage of this project, it would be easy to assume that he just wanted to control some halloween decorations. He is actually a PhD student at the University of Alabama in Huntsville. His research topic is SCADA (aka Industrial Control Systems) cyber security. His goal was to find vulnerabilities in PLCs and, hopefully, fix them. However, no PLC manufacturer releases their source code, and he was having trouble getting a deep understanding of something so closed.

So, since no one was going to open their code and hardware for him he simply made his own. OpenPLC can be programmed in all 5 IEC 61131-3 languages: ST, IL, LADDER, FBD and SFC. On top of that, it lowers the barrier of entry to developing this kind of industrial hardware by being compatible with all the favorites Arduino, Raspberry Pi, Windows, Linux, etc.

“The OpenPLC is the first fully functional standardized open source PLC. We believe that opening the black-box of a PLC will create opportunities for people to study its concepts, create new technologies and share resources.”

CNC Drag Knife Upgrade With Off-the-Shelf Blades

June 5, 2016 by Sonya Vasquez 20 Comments

Drag Knives seem to be the overshadowed awkward kid on the playground of CNC equipment, but they have a definitive niche making stencils, vinyl stickers, and paper cuts. Unfortunately, the drag knife blades for CNC routers are pricey — over $100 for a single blade. [Brian] at the Grunblau Design Studio took the price point as a challenge to build his own end-effector. A few iterations later, he’s created his very own drag knife blade tool that accepts replaceable steel blades for cutting.

From constraint-driven concept, to a 3D printed proof-of-concept, to a fully machined aluminum prototype, [Brian’s] efforts hit all the highlights of a well-engineered project. At the end of the day, dull blades can be swapped for a few dollars, rather than shelling out another $150 for the off-the-shelf variant. We’ve seen bootstrapped CNC vinyl cutters before, but nothing that takes an original re-envisioning of the tool itself.

FR4 Machine Shield Is A CNC Milling Machine From FR4 PCB

June 4, 2016 by Moritz Walter 21 Comments

The people behind the PocketNC heard you like CNC PCB mills, so they milled you a PCB mill out of PCB. They announced their surprising new open source hardware product, a pocket sized 3-axis CNC machine entirely made out of FR4 PCB material, aptly named “FR4 Machine Shield”, at this year’s Bay Area Maker Faire.

UPDATE: The FR4 Machine Shield is now on Kickstarter

We know the concept from quadcopters, little robots, and generally things that are small enough to make use of their PCBs as a structural component. But an entire CNC machine, soldered together from a few dozen PCBs certainly takes it to the next level.

There is no doubt that 2mm thick fiber reinforced epoxy can be surprisingly rigid, although the Achilles heel of this method might be the solder joints. However, it looks like all load bearing, mechanical connections of the machine are supported by tightly interlocking ~~“dovetail”~~ finger-joints, which may help protecting all the solder connections from the strain hardening effects of continuous stress and spindle vibrations.

As you might expect, most of the wiring is embedded into the FR4 frame construction, and to squeeze the maximum value out of the PCB material, the motor driver boards interface via card edge connectors with the (currently Arduino based) controller board. In addition to the milling head, which features a brushless DC motor and a tool coupler, the team wants to develop heads for circuit printing, microscopy, pneumatic pick and place, hot air reflow, and 3D printing.

With all those cost-driven design choices, from the one-step manufacturing process of the frame and wiring to the dismissal of screws and nuts from the frame assembly, the “FR4 Machine Shield” could indeed become one of the cheapest CNC machine kits on the market. The team targets an introduction price of $400 during a Kickstarter campaign in June 2016. Can they deliver? [Gerrit] checked Pocket NC out at the Faire and ended up raving about how they run their business.

Enjoy their teaser video below!

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Mechaduino- Closed Loop Stepper Servos For Everyone

June 1, 2016 by Gerrit Coetzee 50 Comments

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.

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