Electric wheelchairs are responsible for giving back independence to a great many people the world over. They do have their limitations, however, including long recharge times and a general aversion to large amounts of water. Being weatherproof is one thing, but taking one to a waterpark is another thing entirely. Fear not, for The University of Pittsburgh has the answer: the air-powered wheelchair.
Known as the PneuMobility project, the chair relies on a couple of compressed air tanks as a power source. They appear to be a of composite construction, which would cut down on weight significantly and help reduce risk of injury in the case of a failure. The air is passed through a system of valves to a special compressed air motor, allowing the user to control the direction of travel. Unfortunately details on the drive system are scant — we’d love to know more about the design of the drivetrain! Reportedly a lot of the components come from the local hardware store, though we haven’t seen a whole lot of compressed air drive motors on the racks of Home Depot/Bunnings/et al.
Range for the wheelchairs is listed as about 1/3 of an electric wheelchair but recharging compressed air takes minutes, not hours. Developed by the university’s Human Engineering Research Laboratories, the wheelchair isn’t just a one off. There are plans to supply ten of the machines to the Morgan’s Wonderland amusement park to enable wheelchair users to share in the fun of the water park.
We’ve seen some great wheelchair hacks in the past, too – like this chair built specifically for the sand dunes! Video after the break.
Continue reading “Air-Powered Wheelchair Goes Like The Wind”
If you take an object and turn it into something else, does that constitute a hack? Can a musical robot call to question the ethics of firearms exports? If you take a disabled shotgun and turn it into a flute, does it become an art piece? Deep questions indeed — and deliberately posed by [Constantine Zlatev] along with his collaborators [Kostadin Ilov] and [Velina Ruseva].
The Last Gun — a mechano-robotic flute, as [Zlatev] calls it — is built from recovered industrial parts, played using compressed air, and controlled by an Arduino and Raspberry Pi. After graphing the annual arms exports from the United States, the installation plays a mournful tune for each year that they rise, and a jubilant theme for each year they fall.
Continue reading “Mechano-Robotic Flute Made From An Old Shotgun”
What do you want to levitate today? [Latheman666] uses his air compressor to make all kinds of stuff float in mid air. Light bulb, key chain, test tube, ball bearing, tomato… pretty neat trick to try in your shop.
It is interesting to see what physics explain this behavior. The objects do not float just because they are pushed upwards by the airflow, that would be an unstable equilibrium situation. Instead, they obtain lift in a very similar way as the wings of an airplane. Not all objects will levitate using this trick: the object has to be semi-spherical at the top.
[Applied Science] nicely shows this behavior by levitating a screwdriver first, then an identical object but with a flat top. The flat top screwdriver fails to levitate. The curvature provides the path for a smooth airflow, because of the Coanda effect, creating a zone of low pressure at the top, making the situation analogous to that of an airplane wing. Therefore, for this to work, you need an object with some kind of airfoil shaped surface. Another great demonstration is that of [NightHawkInLight], using a high speed camera.
A very impressive experiment that needs nothing more than an air compressor!, we are sure you will try it next time you work with one. For more on this topic of levitation with air streams, check the ping pong ball levitation machine.
Continue reading “Compressed Air Levitation and the Coanda Effect”
Amateur radio is an eclectic hobby, to say the least. RF propagation, electrical engineering, antenna theory – those are the basics for the Ham skillset. But pneumatics? Even that could come in handy for hanging up antennas, which is what this compressed-air cannon is designed to do.
[KA8VIT]’s build will be familiar to any air cannon aficionado. Built from 2″ Schedule 40 PVC, the reservoir is connected to the short barrel by a quarter-turn ball valve. Charging is accomplished through a Schrader valve with a cheap little tire inflator, and the projectile is a tennis ball weighted with a handful of pennies stuffed through a slit. Lofting an antenna with this rig is as simple as attaching a fishing line to the ball and using that to pull successively larger lines until you can pull the antenna itself. [KA8VIT] could only muster about 55 PSI and a 70′ throw for the first attempt shown below, but a later attempt with a bigger compressor got him over 100 feet. We’d guess that a bigger ball valve might get even more bang for the buck by dumping as much air as quickly as possible into the chamber.
Looking to launch a tennis ball for non-Ham reasons? We’ve got you covered whether you want to power it with butane or carbon dioxide.
Continue reading “Pneumatic Launcher Gets Ham Antennas Hanging High”
We’re fascinated by things with no moving parts or active components that work simply by virtue of the shape they contain — think waveguides and resonators for microwave radiation. A similarly mystical device from the pneumatics world is the Hilsch Vortex Tube, and [This Old Tony] decided to explore its mysteries by whipping up a DIY version in his shop.
Invented in the 1930s, vortex tubes are really just hollow tubes with an offset swirl chamber. Incoming compressed air accelerates in the swirl chamber and heads up the periphery of the long end of the tube, gaining energy until it hits a conical nozzle. Some of the outer vortex escapes as hot air, while the rest reflects off the nozzle and heads back down the pipe as a second vortex inside the outer one. The inner vortex loses energy and escapes from the short end as a blast of cold air – down to -50°C in some cases. [Tony]’s build doesn’t quite approach that performance, but he does manage to prove the principle while getting a few good-natured jabs into fellow vloggers [AvE] and [Abom79].
We’ve covered vortex tubes before, but as usual [Tony]’s build shines because he machines everything himself, and because he tries to understand what’s making it work. The FLIR images and the great video quality are a bonus, too.
Continue reading “Peculiar Fluid Dynamics Creates Hot and Cold Air”
One of the major reasons anyone would turn to a 3D printer, even if they have access to a machine shop, is that there are some shapes that are not possible to make with conventional “subtractive manufacturing” techniques. There are a few more obvious reasons a lot of us use 3D printers over conventional machining such as size and cost, but there’s another major reason that 3D printers are becoming more and more ubiquitous. [Crumbnumber1] at Make Anything’s 3D Printing Channel shows us how powerful 3D printers are at iterative design with his air-powered tops. They incorporate fan blades that allow you to spin the top up to very high speeds by blowing air down onto it.
Iterative design is the ability to rapidly make prototypes that build and improve upon the previous prototype, until you’re left with something that does the job you need. Even with a machine shop at your disposal, it can be expensive to set up all of the tooling for a part, only to find out that the part needs a change and the tooling you have won’t work anymore. This is where 3D printers can step in. Besides all of their other advantages, they’re great for rapid prototyping. [Crumbnumber1] made a box full of tops and was able to test many different designs before settling on one that performed above and beyond everything that came before it.
The video below is definitely worth checking out. The design process is well documented and serves as a great model for anyone looking to up their rapid prototyping game.
Continue reading “Air-Powered Top Only Possible on a 3D Printer”
Our most likely exposure to a steam engine these days will probably come courtesy of a railway locomotive. A machine capable of immense power and probably with significant complexity and engineering in its construction, something the majority of us will only ever be able to see at second-hand. But there was a period when steam engines were much more accessible, before internal combustion engines and electric motors took on the task of automating hard work you would have found small stationary steam engines in all corners of industry.
These engines are on a scale much more easily embraced by hackers and makers, and though vintage stationary engines are thin on the ground these days there are a significant number of people pursuing their construction by converting modern petrol and diesel engines to a more old-fashioned medium.
[Lindsay Wilson] has a lawnmower engine which a few years ago he converted with the addition of a sleeve valve to run on compressed air. It’s not a steam engine because creating a safe and legal steam boiler is an expensive process, but despite this it amounts to the same thing. The engine in question is a small sidevalve single cylinder Suffolk Punch lawnmower engine from which he has removed and blocked the valve gear, and added a sleeve valve powered by a linkage from the crankshaft and using the spark plug hole as an inlet and outlet. He provides a lot of detail on the sleeve valve’s construction, and it really is a surprisingly simple arrangement. We might look for a harder metal than copper pipe for the guide in which it runs though.
The video below the break shows the engine being run up after a period of storage. It’s an effective device, easily capable of taking more air than his compressor can supply.
Continue reading “Converting a Lawnmower Engine To Run on Compressed Air”