Chair Dances Like No One Is Watching

Although it might be more accurate to say that this chair dances because no one is watching, the result is still a clever project that [Igor], a maker-in-residence at the National Museum of Decorative Arts and Design in Norway, created recently. Blurring the lines between art, hack, and the ghosts from Super Mario, this chair uses an impressive array of features to “dance”, but only if no one is looking at it.

In order to get the chair to appear to dance, [Igor] added servo motors in all four legs to allow them to bend. A small non-moving dowel was placed on the inside of the leg to keep the chair from falling over during all of the action. It’s small enough that it’s not immediately noticeable from a distance, which helps maintain the illusion of a dancing chair.

From there, a Raspberry Pi 3 serves as the control center for the chair. It’s programmed in Python and runs OpenCV for face detection and uses pigpio for controlling the leg servos. There’s also a web interface for watching the camera’s output and viewing its facial recognition abilities. The web interface also allows a user to debug the program. [Igor]’s chair can process up to 3 frames per second at 800×600 pixels.

Be sure to check out the video after the break to see the chair in action. It’s an interesting piece of art, and if those dowels can support the weight of a person it would be a great addition to any home as well. If it’s not enough chair for you, though, there are some other more dangerous options out there.

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Cheap and Effective Dune Buggy Wheel Chair

[masterfoo]’s mother-in-law suffers from a bad hip which would have sidelined her participation in the Fourth of July festivities. As a testament to the power of family and ingenuity, [masterfoo] built her a beach-capable wheel chair to give her some off-roading capability.

The frame is built out of 1.5″ PVC piping and the tires are 20×8-8″ inner tubes for ride-on lawnmowers. The lawnmower  wheel inner tubes were cost-effective and fit the purpose, saving the need for the more expensive purpose-built-for-the-beach Wheeleez tires. They also have a fluid inside that plugs small punctures which will come in handy against he beach’s small cacti and other flora. This video was their guide for the foam insulation and plywood wheel assembly, also employing the handy man’s secret weapon to protect the tube from the rim’s plywood edge. Check it out in action!

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Gaming Chair gives Full Body Feeling to Collisions

A PS-3 controller has an unbalanced motor inside that vibrates your hand whenever you crash a car into a wall or drive it off a cliff and hit the rocks below but [Rulof Maker] wanted that same feeling all over his body. So he added a serious unbalanced motor to his favorite gaming chair to make his whole body vibrate instead.

To do that he opened up the controller and found the wires going to the unbalanced motor. There he added a small relay, to be activated whenever the motor was energized. Wires from that relay go to a female connector mounted in the side of the controller, keeping the controller small and lightweight.

Next he needed to attach a much bigger unbalanced motor to the underside of his favorite gaming chair. For the unbalanced mass he poured concrete powder and molten lead into a tin can mold and attached the result to the motor’s shaft. Using a piece of wood he attached the motor to the chair’s underside.

All that was left was to power the motor and turn it on when needed. For that he wired up a bigger relay, with the relay’s coil wired to a male connector to plug into the PS-3 controller. Now when the PS-3 wants to vibrate, that relay is energized. All that was left was to wire the relay’s normally open switch, the motor and a power cord in series, plug it into the wall socket, and he was ready to shake.

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Sit ‘n Spin for Big Kids

Humans seem to have a strange love affair with testing their limits, especially when it comes to spinning. Perhaps they ride the Gravitron while dreaming they’re in NASA’s 20 g test centrifuge. When carnival rides aren’t enough though, a few intrepid hackers bust out the welders and take matters into their own hands. This is a hack that goes by many names, though  “The Redneck Spin Chair” will bring up plenty of hits on YouTube.

The design is dead simple. Take a rear differential and axle assembly out of an old car or truck. Rotate it 90 degrees, so the diff is now pointing up. Weld a chair on. Finally, weld on a couple of tow bars. Pulling the whole mess will cause the wheels to spin, which transmits power through the differential and rotates the chair. The ride doesn’t have be pulled very fast, as automotive differentials generally have reduction between 3:1 and 5:1. We’re running things in reverse, so that reduction becomes a multiplier. The result, which can be seen in the video below is a very dizzy rider.

The earliest incarnation of this ride we could find was created at Eagle Mountain in Burtrum, Minnesota. We’re betting this particular hack has been around for decades longer though. The closest in our recent memory is North Street Labs’ Centrifury. Do you know of an earlier incarnation? Let us know in the comments!

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A Simple Posture Sensor


If you are on the computer for a large part of the day, posture becomes a serious issue that can negatively impact your health. [Wingman] saw this problem, and created a hack to help solve it. His simple posture sensor will monitor the position of your head relative to the chair, and reminds you to sit up straight.

The posture sensor is built around the HC-SR04 ultrasonic distance sensor, an Attiny85, and a piezo speaker. We’ve seen this distance sensor used in the past for a few projects. Rather than going down the wearable route, which has its own drawbacks, [Wingman] decided to attach his sensor on the back of his chair. The best part is that the sensor is not mounted directly on the chair, but rather on a piece of fabric allowing it to be easily moved when needed.

Given how low-cost and small the sensor is, the project can be easily expanded by adding multiple sensors in different locations. This would allow the angle of the back and possibly the neck to be determined, giving a more accurate indicator of poor posture. There are very few hacks out there that address bad posture. Do you have a project that helps address bad posture? Have you used video processing or a wearable device to monitor your posture? Let us know in the comments an don’t forget to send post links about them to our tips line.

[Frank] builds a chair from a sequoia

chair[Frank Howarth] is a very competent woodworker known on the YouTubes for his wonderful stop-motion videos of turned wood bowls. Lately, though, he’s put some effort into building furniture, this time a beautiful lawn chair made from a gigantic sequoia log.

A few years ago, [Frank] and a friend acquired a gigantic sequoia log and milled it themselves with a chainsaw. After two summers, the huge boards were finally dry enough to be used and [Frank] decided a lawn chair would be a fine project.

The sides of the chair are a single monolithic piece of wood. Of course [Frank] needed to cut the sides in half and join them together again for the decorative holes, but it’s still an impressively solid piece of woodworking. The back and seat of the chair are also made out of the same sequoia board, cut into slats held together with three very large dowel rods.

This project probably wouldn’t be possible if it weren’t for the awesome equipment and tools [Frank] has in his shop. He has a great tour of his shop available for your viewing. We should all be so lucky.

DRM Chair only works 8 times


Download a song from iTunes, and you can only add that song to the music library of five other computers. Grab a copy of the latest Microsoft Office, and you’d better hope you won’t be upgrading your computer any time soon. Obviously DRM is a great tool for companies to make sure we only use software and data as intended, but outside planned obsolescence, there isn’t much in the way of DRM for physical objects.

This is where a team from the University of Art and Design in Lausanne, Switzerland comes in. They designed a chair that can only be sat upon eight times. After that, the chair falls apart necessitating the purchase of a new chair. Somewhere in the flat-pack furniture industry, someone is kicking themselves for not thinking of this sooner while another is wondering how they made a chair last so long.

The design of the chair is fairly simple; all the joints of the chair are cast in wax with a piece of nichrome wire embedded in the wax. An Arduino with a small switch keeps track of how many times the chair has been used, while a solenoid taps out how many uses are left in the chair every time the user gets up. When the internal counter reaches zero, a relay sends power through the nichrome wire, melting the wax, and returning the chair to its native dowel rod and wooden board form.

Melting wax wasn’t the team’s first choice to rapidly disassemble a chair; their first experiments used gunpowder. This idea nearly worked, but it was soon realized no one on the team wanted to sit on a primed and loaded chair. You can see the videos of the wax model failing after the break.

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