Fishing for AirPods with Magnets

Note to self: if you’re going to hack at 4 in the morning, have a plan to deal with the inevitable foul ups. Like being able to whip up an impromptu electromagnetic crane to retrieve an AirPod dropped out a window.

Apartment dweller [Tyler Efird]’s tale of woe began with a wee-hours 3D print in need of sanding. Leaning out his third-story window to blow off some dust, he knocked one AirPod free and gravity did the rest. With little light to search by and a flight to catch, the wayward AirPod sat at the bottom of a 10-foot shaft below his window, keeping company with a squad of spiders for two weeks. Unwilling to fork over $69 and wait a month and a half for a replacement, [Tyler] set about building a recovery device. A little magnet wire wound onto a bolt, a trashed 100-foot long Ethernet cable, and a DC bench supply were all he needed to eventually fish up the AirPod. And no spiders were harmed in the making of this hack.

Need to lift something a little heavier than an AirPod? A beefy microwave oven transformer electromagnet might be the thing for you. And confused about how magnets even work in the first place? Check out our primer on magnetism.

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LiftLocker Keeps Your Lift Safe from Attacking Garage Doors

Car lifts used to be a tool reserved for professional mechanics. Times are a-changing though. With the advent of reasonably priced four-post hydraulic lifts, more and more shade tree mechanics are joining the five-foot high club. Installing a lift in a home garage creates a few hazards, though. What happens when a family remotely opens the garage door while there is a car up on the lift? Garage door and lifted vehicle will meet – with expensive and/or dangerous results. [Joe Auman] saw this problem coming a mile away. He built the LiftLocker to make sure it never happens to him.

At its core, LiftLocker is a set of switched extension cords. Two cast-aluminum boxes hide the electronics. One box plugs in-line with the lift. The other box plugs in-line with the garage door opener. Each box includes a Sparkfun Redboard Arduino compatible, an RFM22 433 MHz Radio, and a relay. Input comes from a security system magnetic reed-switch. Both boxes are identical in hardware and code.

Operation is simple. One box and reed switch goes on the lift, the other on the garage door. If the lift is going up, its reed switch will open. The lift’s Arduino detects this and commands its RFM22 to send a signal to the other box on the garage door. Upon receiving this signal, the garage door controller will open its relay, disconnecting power to the garage door opener. Communication is two-way, so if the Lift controller doesn’t hear an ACK message from the garage door controller, everything will shut down. Click past the break to see the system in action.

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Heavy Lift Electromagnet from Microwave Oven Transformers

It’s OK, you can admit it — from the time you first saw those huge electromagnetic cranes in scrap yards you’ve wanted to have one. While it may not fling around a car, parts donated from scrapped microwaves can let you build your own electromagnetic lifting device and make that dream finally come true.

We recently watched [MakeItExtreme] turn a couple of microwave oven transformers into a somewhat ill-advised wall-climbing rig. It looks like that may have been the inspiration for this build, and the finished product appears to be a tad more useful this time. The frames of three MOTs are cut open to remove the secondary coils and leave the cores exposed as poles for the future magnets. A shallow dish is fabricated out of steel and the magnets are welded in place.

With the primaries wired together, the magnets are epoxy potted, the business end is faced off cleanly, and the whole thing put to the test. [MakeItExtreme] doesn’t go into control details in the video below, but the website mentions the magnet being powered off a 24V 15A power supply with battery backup in case of mains failure.

They’ve lifted 200kg so far, and it looks like a pretty cool addition to a shop already packed with other builds, like their MOT spot welder and a propane tank sandblaster.

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Scissor Lift Shoes May Be OSHA Compliant

It’s been said that necessity is the mother of all invention. This was probably the fundamental principle behind the show “Inspector Gadget”, a story about a police agent who has literally any technology at his grasp whenever he needs it. Although the Inspector’s gadgets get him into trouble more often than not (his niece Penny usually solves the actual crimes), the Inspector-inspired shoes that [Make it Extreme] built are a little bit more useful than whatever the Inspector happens to have up his sleeve (or pant leg, as the case may be).

If a fabrication tour de force, [Make it Extreme] built their own “Go Go Gadget Legs”, a set of pneumatically controlled stilts that allow the wearer to increase their height significantly at the push of a button. We often see drywall contractors wearing stilts of a similar height, but haven’t seen any that are able to raise and lower the wearer at will. The team built the legs from scratch, machining almost every component (including the air pistons) from stock metal. After some controls were added and some testing was done, the team found that raising one foot at a time was the safer route, although both can be raised for a more impressive-looking demonstration that is likely to throw the wearer off balance.

The quality of this build and the polish of the final product are incredibly high. If you have your own machine shop at home this sort of project might be within your reach (pun intended). If all you have on hand is a welder, though, you might be able to put together one of [Make it Extreme]’s other famous builds: a beer gun.

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We Recommend That You Enter a Cyclocopter From The Front

It’s crazy to think that we’ve optimized the heck out of some types of powered flight when there are entire theories and methods that haven’t even seen many government research dollars, let alone the light of day. The cyclocopter is apparently one of those. It was dreamt up around the same time as a helicopter, but was too audacious for the material science of the time. We have helicopters, but [Professor Moble Benedict] and his graduate students, [Carl Runco] and [David Coleman], hope to bring cyclocopters to reality soon.

For obvious reasons they remind us of cyclocranes, as the wings rotate around their global axis, they also rotate back and forth in a cycloidal pattern around their local axis. By changing this pattern a little bit, the cyclocopter can generate a wide variety of thrust vectors, and, hopefully, zip around all over the place. Of course, just as a helicopter needs a prop perpendicular to its main rotor on its tail to keep if from spinning around its axis, the cyclocopter needs a prop facing upwards on its tail.

It does have a small problem though. The bending force on its wings are so strong that they tend to want to snap and fly off in all different directions. Fortunately in the past hundred years we’ve gotten ridiculously good at certain kinds of material science. Especially when it comes to composites we might actually be able to build blades for these things. If we can do that, then the sky’s the limit.

[Professor Benedict] and his team are starting small. Very small. Their first copter weighs in under 30 grams. It took them two years of research to build. It will hopefully lead to bigger and bigger cyclocopters until, perhaps, we can even build one a person can get into, and get out of again.

Hacker Helps His Mother Lift Her Walker When He’s Not There

[typo]’s mother gets around with a walker. It’s a great assistive device until she has to lift the heavy thing up into her car. Noting that this was a little cruel he did as any hacker would and found a way to automate the process.

The build is pretty cool. She had to give up her passenger seat, but it’s a small price to pay for independence. He removed the door paneling on the passenger side. Then he welded on a few mounting points. Next he had to build the device.

The well-built device has a deceptively simple appearance. The frame is made from CNC milled panels and the ever popular aluminum extrusion. It uses a 12V right angle drive and some belting to lift the chair. There’s no abundance of fancy electronics here. A toggle switch changes the direction of the motor. There are some safety endstops and an e-stop.

Now all she has to do is strap the walker to the door. She picks the direction she wants the lift to go and presses a button. After which she walks the short distance to the driver’s seat, and cruises away.

Maybe Your Next Robot Should Be a Cyclocrane

At my university, we were all forced to take a class called Engineering 101. Weirdly, we could take it at any point in our careers at the school. So I put it off for more interesting classes until I was forced to take it in one of my final years. It was a mess of a class and never quite seemed to build up to a theme or a message. However, every third class or so they’d dredge up a veritable fossil from their ranks of graduates. These greybeards would sit at the front of the class and tell us about incredible things. It was worth the other two days of nondescript rambling by whichever engineering professor drew the short straw for one of their TAs.

The patent drawing.
The patent drawing.

One greybeard in particular had a long career in America’s unending string of, “Build cool stuff to help us make bad guys more deader,” projects. He worked on stealth boats, airplanes with wings that flex, and all sorts of incredibly cool stuff. I forgot about the details of those, but the one that stuck with me was the Cyclocrane. It had a ton of issues, and as the final verdict from a DARPA higher-up with a military rank was that it, “looked dumb as shit” (or so the greybeard informed us).

A Cyclo-What?

The Cyclocrane was a hybrid airship. Part aerodynamic and part aerostatic, or more simply put, a big balloon with an airplane glued on.  Airships are great because they have a constant static lift, in nearly all cases this is buoyancy from a gas that is lighter than air. The ship doesn’t “weigh” anything, so the only energy that needs to be expended is the energy needed to move it through the air to wherever it needs to go. Airplanes are also great, but need to spend fuel to lift themselves off the ground as well as point in the right direction. Helicopters are cool because they make so much noise that the earth can’t stand to be near them, providing lift. Now, there’s a huge list of pros and cons for each and there’s certainly a reason we use airplanes and not dirigibles for most tasks. The Cyclocrane was designed to fit an interesting use case somewhere in the middle.

In the logging industry they often use helicopters to lift machinery in and out of remote areas. However, lifting two tons with a helicopter is not the most efficient way to go about it. Airplanes are way more efficient but there’s an obvious problem with that. They only reach their peak efficiency at the speed and direction for which their various aerodynamic surfaces have been tuned. Also worth noting that they’re fairly bad at hovering. It’s really hard to lift a basket of chainsaws out of the woods safely when the vehicle doing it is moving at 120mph.

The cyclocrane wanted all the efficiency of a dirigible with the maneuverability of a helicopter. It wanted to be able to use the effective lifting design of an airplane wing too. It wanted to have and eat three cakes. It nearly did.

A Spinning Balloon with Wings

Four wings stick out of a rotating balloon. The balloon provides half of the aerostatic lift needed to hold the plane and the cargo up in the air. The weight is tied to the static ends of the balloon and hang via cables below the construction. The clever part is the four equidistant wings sticking out at right angles from the center of the ship. At the tip of each wing is a construction made up of a propellor and a second wing. Using this array of aerofoils and engines it was possible for the cyclocrane to spin its core at 13 revolutions per minute. This produced an airspeed of 60 mph for the wings. Which resulted in a ton of lift when the wings were angled back and forth in a cyclical pattern. All the while, the ship remaining perfectly stationary.

There’s a really great description of its operation in the article this photo came from.


It really didn't like strong winds.
It really didn’t like strong winds.

Now the ship had lots of problems. It was too heavy. It needed bigger engines. It was slow. It looked goofy. It didn’t like strong winds. The biggest problem was a lack of funding. It’s possible that the cyclocrane could have changed a few industries if its designers had been able to keep testing it. In the end it had a mere seven hours of flying time logged with its only commercial contract before the money was gone.

However! There may be some opportunity for hackers here. If you want to make the quadcopter nerds feel a slight sting of jealousy, a cyclocrane is the project for you. A heavy lift robot that’s potentially more efficient than a balloon with fans on it is pretty neat. T2here’s a bit of reverse engineering to be done before a true performance statement can be made. If nothing else. It’s just a cool piece of aerospace history that reminds us of the comforting fact that we haven’t even come close to inventing it all yet.

If you’d like to learn more there’s a ton of information and pictures on one of the engineer’s website. Naturally wikipedia has a bit to say. There’s also decent documentary on youtube, viewable below.

Photo Credits: Rob Crimmins and Hal Denison