Hackaday Links: August 30, 2015

A month ago, we ran a post about [Jim]’s rare and strange transparent microchips. He’s back at it again, this time taking a look at the inner workings of MOSFETs

The Unallocated Space hackerspace is moving, and they’re looking for a few donations to get the ball rolling.

Yes, it’s a Kickstarter for a 3D printer, but the LumiPocket is interesting, even if only on the basis of the engineering choices. It’s a UV laser resin printer, and they’re using a SCARA arm to move the laser around. They’re also doing a top-down resin tank; it requires more resin, but it seems to work well enough.

Around DC or northern Virginia? We’re going to be there on September 11th through the 13th. We’re holding a Hackaday Prize Worldwide meetup at Nova Labs in Reston, Virgina. Sign up now! Learn KiCAD with [Anool]! Meet [Sudo Bob]! It’ll be a blast.

Not around DC or NOVA? This Wednesday we’ll be hosting another chat on .io.

The GEnx is one of the most advanced engines in the world, and that means [Harcoreta] oven on the RC groups forums has made one of the most beautiful electric ducted fans in the world. On the outside, it looks like a GEnx, including reverse thrust capabilities, but inside it’s pure electronics: a brushless motor rotates a 100mm, 18-blade fan. He’s hoping to mount it on a Bixler (!). We can’t wait for the video of the maiden.

Bipolar bot for drawing spirals

[Bart Dring] is well known around these parts for Makerslide, the buildlog.net laser cutter, and a collaboration with Inventables for the Carvey CNC machine. They’re all popular projects and all very useful. This one, not so much. It’s a bipolar bot that doesn’t take itself too seriously, and this year’s build for [Bart]’s usual gonzo CNC machine for ORD Camp.

The Bipolar Bot – yes, that’s its name – is pretty much a SCARA bot. There are two NEMA 14 steppers in the joint of two arms, each of which are bolted to a bearing on a base plate with the other end holding a pen. That’s it as far as the mechanics go, but the software is extremely interesting.

The steppers are driven by an Arduino with the help of a tool that converts Cartesian Gcode to the bipolar Gcode the machine requires. There’s a bit of math involved, but nothing of note if you can code some trig functions

Right now the bipolar bot is busy drawing stuff that looks like it came right off a spirograph. You can see a video of that below.

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Learn Engineering and Draw Narwhals

narwhals

Using LEGO robots and other ‘intro to robotics’ platforms is a great introduction to kinematics and programming, but if you’re teaching a classroom of people who don’t know what a 1/4-20 screw is, perhaps it’s not the right introduction to engineering. That’s the thinking behind NarwhalEdu’s upcoming, Kickstarted online course: give kids a bunch of servos, bolts, and a microcontroller, and they’ll be able to build anything, and not just what the instructions for a Mindstorm’s robot says.

Robots, Drawing, and Engineering is an online course built around a simple SCARA arm robot. It’s made out of laser cut hardboard and powered by three servos and an Arduino Nano with an extension shield. After building this robot in the first hour of the online class, students then learn a little programming and get their robot drawing everything from narwhals to nyan cats and faces.

In the second part of the course, students then tear apart their robot kit and start making other, cooler interesting devices. There’s a contest for the coolest project that will hopefully go a long way to show how creative engineering can be.

Two videos below of the NarwhalEdu SCARA arm in action.

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RepRap Wally Can Print Larger Versions of Itself

SCARA based 3D printers seem to be all the rage these days, and with good reason. This RepRap Wally doesn’t use any linear rods or timing belts — in fact, it can even print larger versions of itself with each iteration! Well, minus the electronics of course.

It was first spotted out in the wild at the NYC Makerfaire, and looks to be a pretty slick design. Using fully 3D printed limbs, the steppers move the arms using a fishing line. To reduce the load on the joints, a bowden extruder is also used. The really cool part of this is the z-axis, it uses a 4-bar linkage to stay level, but because of this, it also moves along an arc in the y-axis as it raises or lowers. This is accounted for in the firmware — otherwise you’d have some rather interesting curved prints!

Stick around after the break to see it in action, it’s a nice change to watch from the standard gantry style printers.

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SCARA Arm Becomes Enormous 3D Printer

SCARA

When you find an old, disused 80s-era SCARA arm in a lab, there’s really not much more you can do than make a giant 3D printer with it.

The last time we saw [Dane]’s salvaged SCARA arm, he had reconstructed the electronics by building his own servo motor controllers and feedback sensors. There were a few initial test prints, but the new upgrades to this printer make it much more useful, make it look even more kludged together, and made the prints even more accurate.

The largest upgrade to the new machine is an updated heated build plate. The previous plate used six 30W resistors. Good enough, but with two additional 245W membrane heaters, [Dane] can now keep his build plate at a constant 65 degrees C. Keeping such a large area warm requires a heated build chamber, so [Dane] came up with a giant semi-hexagonal box of warm made from aluminum extrusion, laser-cut parts, and acrylic frames.

Compared to earlier prints, the SCARA arm is printing some very nice parts including a battery holder for 40 LiFePO4 cells, and a beautiful propeller for a 3D printed boat. It’s an impressive build, made even more so by the fact this robotic arm was found during a lab cleanup.

Handwriting robot arm is a little stiff-wristed

handwriting-robot

Check out this robot arm capable of handwriting which is orders of magnitude clearer than our own. It was built by [Patrick Barnes] as contract work for a campaign to raise funding for research into Duchenne Muscular Dystrophy.

Don’t miss the video after the break which starts off with the satisfying whine of some serious stepper motors. Judging scale from this image is a bit tough, but [Patrick] tells us that the entire assembly stands almost fourteen inches tall and the arm has a reach of around twenty inches. The demonstration shows off it’s abilities by drawing a Hilbert Curve. From watching the action you’ll realize that, though this arm and hand look fantastic, this is really a SCARA plotter. The wrist and fingers are for looks only, providing a place where the felt-tipped pen can be mounted (held flush to the paper with a rubber band). Whether that’s a disappointment or not, the precision and look of the machine bring it very high marks. It could take a bit of a lesson in penmanship from another we’ve seen though.

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SCARA arm finally prints plastic parts

SCARA

Here’s a neat alternative to the usual gantry setup you see on 3D printers. [Quentin] designed and build a SCARA arm 3D printer that just saw its first print.

We caught wind of [Quentin]’s SCARA arm a few weeks ago when it was still just a few plastic parts and a glimmer of ambition in its creator’s eye. Most of the parts are 3D printed, including the blue arms for the x and y axes that are driven by stepper motors. The z axis is controlled by two lead screws, and judging by the height of [Quentin]’s machine, he has a pretty big printable volume – at least as large as some of the delta bot 3D printers we’ve seen.

So far [Quentin] has printed a handful of calibration cubes and a wheel with a fairly impressive print resolution. You can check out a video of the SCARA arm printer after the break.

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