Finally, A Differently Useless Machine

September 20, 2020 by Kristina Panos 32 Comments

Traditionally, the useless machine is a simple one that invites passersby to switch it on. When they do, the machine somehow, some way, turns itself off; usually with a finger or finger-like object that comes out from the box in what feels like an annoyed fashion. Honestly, that’s probably part of what drives people to turn them on over and over again.

But [Bart Blankendaal] has managed to turn the useless machine on its head. When this machine is switched to the on position, unseen forces inside the box will spin the toggle switch around 180° to the off position.

What’s really happening is that an Arduino is getting a signal from the toggle switch, and is then rotating it on a ball bearing with a stepper motor driven through an H-bridge.

It shouldn’t be too hard to make one of these yourself, given that [Bart] has provided the schematic and STLs. If we weren’t living in such touchy times, we might suggest building one of these into your Halloween candy distribution scheme somehow. Sell the switch as one that turns on a candy dispenser, and then actually dispense it after three or five tries.

Many see useless machines as tangible examples of existential quandary. Here is one that takes that sentiment a bit further by snuffing out a candle.

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Open-Source Robotic Arm For All Purposes

September 15, 2020 by Bryan Cockfield 23 Comments

A set of helping hands is a nice tool to have around the shop, especially if soldering or gluing small components is a common task. What we all really want, though, is a robotic arm. Sure, it could help us set up glue or solder but it can do virtually any other task it is assigned as well. A general-purpose tool like this might be out of reach of most of us, unless we have a 3D printer to make this open-source robotic arm at home.

The KAUDA Robotic Arm from [Giovanni Lerda] is a five-axis arm with a gripping tool and has a completely open-source set of schematics so it can be printed on any 3D printer. The robot arm uses three stepper motors and two servo motors, and is based on the Arduino MEGA 2560 for control. The electrical schematics are also open-source, so getting this one up and running is just an issue of printing, wiring, and implementing some software. To that end there are software examples available, and they can easily be modified to fit one’s robotic needs.

A project like this could be helpful for any number of other projects, or also just as a lesson in robotics for yourself or even in a classroom, since many schools now have their own 3D printers. With everything being open-source, this is a much simpler endeavor now than other projects we’ve seen that attempted to get robotic arms running again.

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Encouragement Machine Battles Your Inner Bully

August 18, 2020 by Kristina Panos 1 Comment

We would be preaching to the choir if we told you that fear is the action killer when it comes to the challenge of new projects in uncharted territory. Everyone who reads Hackaday knows that it takes mettle to forge through the self-doubt as we push ourselves to new engineering heights.

[JBV Creative] hears the voice, too: the one that says you can’t build that thing, it’s too difficult/useless. He knows that both creativity and anti-creativity stem from the same source — the powerful human mind that dreams up these projects in the first place.

The Encouragement Machine combines the two in a piece that engineers art from garbage, aka negative thoughts. It works by first acknowledging the most basal of discouraging thoughts — an important step of the process — and then it simply trims away the negativity.

This machine uses a stepper motor to feed receipt paper underneath a custom stamp that says YOU CAN’T DO IT. Then it passes the paper through a pair of servo-driven scissors that snip off the apostrophe-t.

Ironically or not, [JBV Creative] ran into a few issues with this build, but managed to muster up enough moxie to work through the problems without encouraging slips of paper. We have to wonder how much more smoothly the next project will go given all the positivity he now has on-demand.

[JBV] doesn’t delve into the electronics much, but it looks like an Arduino and a motor driver to us. We totally dig the design — it looks like an electrical substation or rocket launch pad that happens to have a Ferris wheel. Step right up and check out the build video after the break.

Generic encouragement is great all-purpose attitude adjuster, but what if you want more specific sentiments? Here’s an affirmation mirror that will help you believe whatever you program into the scrolling display.

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Four Steppers Make A Four-Voice MIDI Instrument

August 15, 2020 by Jenny List 17 Comments

Any owner of a budget 3D printer will tell you that they can be pretty noisy devices, due to their combinations of stepper motors and drives chosen for cost rather than quiet. But what if the noise were an asset, could the annoying stepper sound be used as a musical instrument? It’s a question [David Scholten] has answered with the Stepper Synth, a device that takes an Arduino Uno and four stepper motors to create a four-voice MIDI synthesiser.

Hardware-wise it’s as simple as you’d expect, a box with four stepper motors each with a red 3D-printed flag on its shaft to show rotation. Underneath there is the Arduino, plus a robot control shield and a set of stepper driver boards. On the software side it uses MIDI-over-serial, so as a Windows user his instructions for the host are for that operating system only. The Arduino makes use of the Arduino MIDI library, and he shares tips on disabling the unused motors to stop overheating.

You can hear it in action in the video below the break, and we’re surprised to say it doesn’t sound too bad. There’s something almost reminiscent of a church organ in there somewhere, it would be interesting to refine it with an acoustic enclosure of some kind.

This isn’t the first such instrument we’ve brought you, for a particularly impressive example take a look at the Floppotron.

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The Redesigned CNC Scroll Saw Rides Again

August 6, 2020 by Tom Nardi 18 Comments

When [Andrew Consroe] tried to build a CNC scroll saw, he quickly learned how tricky of a design problem it is. With a blade that only cuts in one direction, you can’t simply move the tool in the X and Y dimensions like you can with a laser or router; either the work piece or the blade itself needs to continuously rotate towards the direction of the cut.

He’s recently shown off the third version of the machine, and while it’s still not exactly a practical tool, there’s no question it’s a brilliantly designed one, or that it works, slowly. Earlier attempts used a rotating table to spin the work piece, but [Andrew] found this to be an imperfect solution. Building a mechanism heavy duty enough to spin the material being cut while remaining accurate enough not to break the blade was a tall order, though he did get pretty close.

The earlier version used a rotating table.

This time around he’s decided to simply rotate the blade itself. This can be accomplished with a single stepper motor and some suitably sized pulleys, while maintaining an exceptionally high degree of accuracy. The whole blade assembly moves up and down on an aluminum extrusion rail with a motor and crank arrangement. By synchronizing the rotation of the blade with the vertical movement of the saw, the software can be sure that everything is where it needs to be before the cutting stroke actually happens.

Judging by the video after the break, the system works quite well. The complex rounded shapes he cuts out of the piece of plywood look essentially perfect, and it sounds like this new version of the machine isn’t breaking blades due to positional errors like the previous one did. Unfortunately, it’s also very slow. There’s so many moving parts and careful positioning required that even when the video is sped up 10x, the saw still appears to only be creeping its way through the material.

On the back half of the video, [Andrew] details another approach to rotating the blade that would reduce the amount of moving mass in the saw. This would give the machine a considerable speed boost, and we’d love to see him implement it. By the way, before anyone says it: using a spiral blade is cheating.

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This Soap Dispenser Will Crush Your Germs

July 17, 2020 by Sharon Lin 12 Comments

When it comes to cleaning your hands, [Arnov Sharma] is not messing around. He built an automatic soap dispenser using ultrasonic sensors, a stepper motor for activating the pump, and 3D printed components for housing a bottle of soap – a spectacular display of over-engineering. At least he won’t be needing to stand in line at the supermarket for motion detection soap dispensers anytime soon.

Initially, he had the idea to build the dispenser using a common servo motor-based method. This would involve activating motors to push down on the plunger for the soap bottle to dispense soap. Instead, he for a different approach that ended up being fairly straightforward in theory, although the execution is pretty involved.

Model of the soap dispenser made in Fusion 360

He started off by 3D printing the compartment where the soap bottle would sit and the structural support for the Z-axis rail that would be pushing down on the soap bottle. It’s similar to the type of linear actuator you might find in a 3D printer or PCB mill, where a motor controls a rotating screw that moves the carriage across a belt. (We presume the linear rail came first, and the ultrasonic soap dispenser second.)

In this build, there are two additional rods added to help support the lever pressing down on the soap dispenser.

The setup is controlled by an Arduino, which triggers the movement from the linear actuator if it receives a signal from an ultrasonic sensor. He’s added the model files and Arduino code for other makers curious about building a similar project. Check out his video for the soap dispenser in action – the stepper motor definitely makes for a much more powerful plunge than you might expect.

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Time Bandit Clock Hits The Aesthetic Jackpot

July 6, 2020 by Kristina Panos 11 Comments

When was the last time you looked forward to looking at a clock? Not to find out the time per se — like gee, maybe it’s beer o’ clock already — but waited with bated breath to gaze upon a particular clock? Never? We don’t blame you, but only because you haven’t seen this fruit machine clock in action yet.

Every 60 seconds, the reels start spinning like some little man inside pulled the lever on a slot machine (or fruit machine, as they’re called across the pond). The reels slow down and stop one by one, left to right, settling on the four digits of time in 24-hour mode. Imagine the suspense of coming to see what time it is just as the reels start spinning!

[timebanditclock] grew this fruit machine out of old-school discrete logic beautifully applied to stripboard. Each of the reels has a DIY binary encoder that uses IR transmit/receive pairs to generate a binary word. These four binary words are compared to a binary clock module using comparators.

We think this is an amazing concept already, but then [timebanditclock] worked overtime by doing it all in discrete logic. Spin past the break to see a demo and stick around for the build video.

Want a challenging clock build that’s a little less challenging? Maybe it’s time to try circuit sculpture.

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