76-bit Trombones Led By The Big MIDI File

Inspired by the creative genius of Martin Molin of Wintergatan fame, [iSax] set out to create a robotic MIDI-controlled trombone. It takes years for humans to develop the control and technique required to play the trombone well as the tone produced into the mouthpiece (embouchure) is a tricky combination of air pressure, lip tension, airflow, resonance in the mouth, and other sources of complex pressure.

[iSax] gives a thorough walkthrough of the machine, which is powered by two separate sources of air, one for the position of the slide and the other for producing sound. A potentiometer provides feedback on the position of the slide and a servo controls the flow rate into the silicone resonance chamber. The chamber can be tuned via a stepper motor that applies pressure, slightly altering the chamber’s frequency and pressure. An Arduino with Firmata allows the device to controlled easily from any host computer. A detailed writeup in PDF form is on the Hackday.io project page.

As you can imagine, simulating a human mouth is a daunting task and the number of variables meant that [iSax] ended up with something only vaguely trombone-like. While ultimately it didn’t turn out to be the astounding music machine that [iSax] hoped, it did end up being a fun feat of engineering we can appreciate and admire. Progress towards automatic brass instruments seems to be coming slowly as we saw similar results with this robotic trumpet. Maybe someday we’ll have robot brass sections, but not today.

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Robust Water-Rocket Launcher Gets The Engineering Just Right

Normally when we run across a project that claims to be overengineered, we admit that we get a little excited. Such projects always hold the potential for entertainingly over-the-top designs, materials, and methods. In this case, though, we’ll respectfully disagree with [Zach Hipps] assessment of his remote-controlled soda bottle rocket launcher as “overengineered”. To us, it seems just right.

That’s not to take away from anything accomplished with this build. Indeed, we’re mighty impressed by the completeness of the build, which was intended to create a station for charging and launching air-powered water rockets. The process started with a prototype, built mainly from 3D-printed parts but with a fair selection of workshop scraps to hold it together. This allowed [Zach] to test the geometry of the parts, operation of the mechanism, and how it interfaced with the flange on the necks of 2-liter soda bottles.

Honestly, the prototype was pretty good by itself and is probably where many of us would have stopped, but [Zach] kept going. He turned most of the printed parts into machined aluminum and Delrin, making for a very robust pneumatically operated stand. We’ve got to say the force with which the jaws close around the bottle flange is a bit scary — looks like it could easily clip off a wayward finger. But if he manages to avoid that fate, such a hearty rig should keep [Zach] flying for a long time. Perhaps it could even launch a two-stage water rocket?

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Robotic Worm Uses NinjaFlex Filament

If you think about building a moving machine, you probably will consider wheels or tracks or maybe even a prop to take you airborne. When [nwlauer] found an earthworm in the garden, it inspired a 3D-printed robot that employs peristaltic motion. You can see a video of it moving, below.

The robot uses pneumatics and soft plastic, and is apparently waterproof. Your printer’s feed path has to be pretty rigid to support flexible filament without jamming. There’s also some PVA filament and silicone tubing involved.

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Assistive Gloves Come In Pairs

We have to hand it to this team, their entry for the 2020 Hackaday Prize is a classic pincer maneuver. A team from [The University of Auckland] in New Zealand and [New Dexterity] is designing a couple of gloves for both rehabilitation and human augmentation. One style is a human-powered prosthetic for someone who has lost mobility in their hand. The other form uses soft robotics and Bluetooth control to move the thumb, fingers, and an extra thumb (!).

The human-powered exoskeleton places the user’s hand inside a cabled glove. When they are in place, they arch their shoulders and tighten an artificial tendon across their back, which pulls their hand close. To pull the fingers evenly, there is a differential box which ensures pressure goes where it is needed, naturally. Once they’ve gripped firmly, the cables stay locked, and they can relax their shoulders. Another big stretch and the cords relax.

In the soft-robotic model, a glove is covered in inflatable bladders. One set spreads the fingers, a vital physical therapy movement. Another bladder acts as a second thumb for keeping objects centered in the palm. A cable system draws the fingers closed like the previous glove, but to lock them they evacuate air from the bladders, so jamming layers retain their shape, like food in a vacuum bag.

We are excited to see what other handy inventions appear in this year’s Hackaday Prize, like the thumbMouse, or how about more assistive tech that uses hoverboards to help move people?

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Hand Depanelizer Gets Pneumatic Upgrade

In high volume production, smaller PCBs are often “panelized” so that multiple copies can be shuffled through assembly as a single piece. Each board is attached to the panel with a few strategically placed tabs, not unlike the sprues in a plastic model kit. If you only have to separate a few boards you can simply cut them with a hand nipper, but when you’re doing hundreds or thousands of boards, it quickly becomes impractical.

Which is where [Clough42] found himself recently. Looking to improve the situation without breaking the bank, he decided to automate his trusty hand-held depanelizer tool. The basic idea was to build an actuator that could stand in for his own hand when operating the tool. He already had a pneumatic cylinder that he could power the device with, he just needed to design it.

In the video below, he walks the viewer though his CAD design process for this project. His first step, which is one that’s often overlooked by new players, is creating digital representations of the hardware he’s using. This allows him to quickly design 3D printed parts that have the proper dimensions and clearances to interface with his real-world components. Remember: it’s a lot easier to adapt your 3D model to the components on hand than the other way around.

With the appropriate valves, hoses, and a foot pedal attached to the pneumatic cylinder, he’s able to operate the cutter completely hands-free. He still has to manually move the panel around, but at least it saves him from the repetitive squeezing motion.

With a tool like this and a custom testing jig, you’ll be producing PCBs like the pros in no time.

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Pneumatic Glove For Therapy And Experimentation

Many projects have aimed to replicate the function of the human hand, creating robotic structures that mimic real anatomy. Fewer have attempted to work with human hands directly. SoftGlove is a project by [france.bonde] that uses pneumatics to do just that.

The glove works by using a silicone pneumatic actuator for each digit on the human hand, attached to a glove. These are created with 3D printed molds, into which EcoFlex silicone is poured. A FlowIO device is used to run the pneumatics, which combines a microcontroller with penumatic hardware to pump air in and out of the actuators.

The goal of the project is to use a companion unit, in which a glove with flex sensors is used to make the SoftGlove mimic its movements. This would allow SoftGlove to move the fingers of a person with damaged muscle control, potentially aiding the muscles and nerves to recover when used in a therapeutic setting.

It’s exciting to see typical maker technologies used in a context to create better outcomes for patients, and we’re excited to see where this project leads next. It also has potential applications for robotic actuators, too. Programmable Air is another exciting project working in this space, too. And of course, if you’ve got a hot pneumatics project you’re cooking up in the garage, be sure to let us know!

Stacks Of Spring Washers Power The Drawbar On This CNC Mill Conversion

With Tormach and Haas capturing a lot of the entry-level professional market for CNC machines, we don’t see too many CNC conversions of manual mills anymore. And so this power drawbar conversion for a Precision Matthews mill really caught our eye.

What’s that, you say? Didn’t [Physics Anonymous] already build a power drawbar for a mill? They did, and it was quite successful. But that was based on a pneumatic impact wrench, and while it worked fine on a manual mill, the same approach would be a bit slow and cumbersome on a CNC mill. For this build, they chose a completely different approach to providing the necessary upward force to draw the collet into the collet holder and clamp down on the tool: springs. Specifically, Belleville spring washers, which are shaped like shallow cups and can exert tremendous axial force over a very short distance.

[PA] calculated that they’d need to exert 2,700 pounds (12,000 Newtons) of force over a length of a couple of inches, which seems outside the Belleville washer’s specs. Luckily, the springs can be stacked, either nested together in “series” to increase the load force, or alternating in “parallel” to apply the rated force over a greater distance. To compress their stack, they used a nifty multi-stage pneumatic cylinder to squash down the springs and release the collet. They also had to come up with a mechanism to engage to machine’s spindle only when a tool change is called for. The video below details the design and shows the build; skip to 11:32 to see the drawbar in action.

We’re looking forward to the rest of [Physics Anonymous]’ conversion. They’re no strangers to modifying off-the-shelf machines to do their bidding, after all – witness their improvements to an SLA printer.

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