Thumper The T-Shirt Launcher

June 25, 2011 by Noah Dunker 46 Comments

[joe] and [ryan] built Thumper for their high school FIRST robotics team. The cannon itself is a solenoid-fired compressed air launcher that gets its juice from three large PVC tanks stored in the box below the turret, and the cannon is able to be fired nine times between visits to the air compressor. It was intentionally designed to resemble an M2 Browning 50 Caliber heavy machine gun, with the two vertical handles and boxy body. They finished construction in about a week with a budget of only $300. When they saw that a lot of their friends had also built cannons, they scrounged for parts from their garages to re-use to build the mobile platform simply for one-upmanship sake. The motor and drive-train propelling this behemoth came out of a 1980s-era mobile X-Ray machine that had been discarded by a local hospital. The rear wheels were specially modified to fit the drivetrain, and the front end is a chopped, hacked, and welded axle and steering mechanism from an old lawn tractor. Sections of unistrut form the rest of the frame.

[joe] and [ryan] were even asked to bring Thumper to their high school prom as a unique way to hand out T-Shirts for the evening. Unfortunately, there’s no website for this build.

See video of Thumper in action with a Nerf Football after the break. Hack A Day even got to take it for a spin around the Power Wheels Racing Series track at Maker Faire KC!

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Washing Machine Mechanical Timer Replaced With Microcontroller

June 5, 2011 by Mike Szczys 12 Comments

After the electromechanical timer on [Paul Canello’s] washing machine broke for the third time he decided he needed to stop repairing it and find a more permanent fix. He decided to build his own microcontroller-based system for washing his clothes (translated). Caution: The image links on [Paul’s] page seem to be broken and will unleash a never-ending storm of empty pop-up windows if you click on them. We’ve embedded all of the images after the break to save you some hassle.

The controller on a washing machine is nothing more than a mechanical alarm clock. It starts the cycle, then moves through various modes based on the passage of time. [Paul] started his hack by observing how long the delay between cycles was meant to be, and recording which parts of the machine were switched on and off at each stage.

It turns out that when the mechanical knob is turned, it reroutes how water flows through the detergent chamber. Since that knob won’t be in the new system [Paul] came up with a way for the microcontroller to handle this by using a servo motor. The rest of the control involves relays to control the motor, and solenoid valves for the water. There are also pressure switches that give feedback for the level of the water in the machine. A PIC 16F872 serves as the new controller, with the help of a 7 segment display, a buzzer, and a pair of buttons as the user interface.

This is an older project, but after reading about the Arduino controlled dishwasher [Ramiro] sent us a link. Thanks! Continue reading “Washing Machine Mechanical Timer Replaced With Microcontroller” →

Valentine’s Day Love Song Machine

February 14, 2011 by Mike Nathan 13 Comments

tellart_bell_ensemble

Just in time for Valentine’s day, [Adam Meyer] and the folks over at tellart.com have put together a little project they call the “Love Song Machine“. Using a web-based form, anyone can submit a song, which will then be played on a system of bells that they have set up in their office. You can choose from several pre-defined love songs, or you can create your own unique arrangement with which to serenade them. Once you are ready to go, your song will be queued up, and you can watch a video of your creation as it is being played.

The system is comprised of 8 solenoid-actuated bells which are all controlled by the Arduino they have hooked up to their web server. It’s a pretty fun idea, and there are sure to be plenty of people submitting songs, so get yours in before things get too busy!

Keep reading to see a video preview of their system in action.

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Magnetic Digital Scale

January 21, 2011 by Mike Szczys 20 Comments

Above you see a solenoid being used as a digital scale. The magnetic field from the coil in the base levitates the platform above, where a load to be measured is place. This floating platform has a permanent magnet in it, hovering above a hall effect sensor in the base. As the distance between that magnet and the sensor changes, the measurable magnetic field changes as well. The hall effect sensor is linear so the measured value can easily be correlated with a weight. In the video after the break [Vsergeev] demonstrates the device using test weights to show off its 0.5 gram resolution. He thinks that with a few hardware improvements he could easily achieve 0.1g accuracy.

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Flaming Guitar Hero

January 5, 2011 by Mike Szczys 17 Comments

[Chris Marion] knew he wanted to play with fire, or more accurately with fireball spewing valves, but he need a good project in which he could use them. Inspiration finally struck and he built this controller that matches fireballs to the fret buttons on a Guitar Hero controller. There’s quite a lot that goes into this but we think that he hit a home run. The basic components are a manifold with electronically actuated valves, another manifold for the pilot lights, and a modified Guitar Hero controller.

To interface the controller he used an Arduino along with [Bill Porter’s] PS2 library to read signals from the buttons. But the real labor intensive part of the build came with the manifold. There’s a hardware store’s worth of fittings and flexible copper pipe that go into that assembly. In the end this all came together in just one week.

[Thanks Bill]

RC Plane Built Using Pieces Of An RC Car

December 11, 2010 by Mike Szczys 17 Comments

This hack’s old as dirt to be sure, but new to us and a great accomplishment. The plane above, which is meant to fly without an operator, has been given RC control thanks to parts from that little car. The transmitter and receiver pair are the obvious transplant, but how do you add steering to a $7 plane that wasn’t manufactured to have that feature? The tail was cut and reconnected with mylar hinges to turn it into a rudder. A rare earth magnet and a coil are also thrown into the mix to provide movement. Basically this is a simple solenoid where the coil pushes against the magnet when energized, actuating the rudder. This in combination with an upgraded motor allows for both speed control and yaw. It doesn’t look like you can control roll and pitch but what more can you really expect?

This would be a nice first step on that path to building an epic flying camera rig.

[Thanks Rob]

Make Your Own Solenoids, Then Play The Xylophone

December 2, 2010 by Mike Szczys 25 Comments

Learn to manufacture your own solenoids and then use them to play the xylophone by watching the tutorial video after the break. [Humberto Evans] and the team at Nerd Kits do a great job of not only manufacturing the coils, but the xylophone itself. The bars are machined from some aluminum stock and they take you down the rabbit hole with they why’s and how’s of engineering the keys.

We’re unlikely to replicate this machining process but the solenoids are another story all together. Starting at about 3:30 you can learn about designing, building, and using these little marvels. They’re basically an electromagnetic cuff with a metal slug in the middle. The solenoid seen above uses a body milled from HDPE and wrapped with magnet wire. The slug in the center is steel, with a few rare-earth magnets at the top. When you run current through the coil it repulses the magnets on the slug, witch then strikes the xylophone key. Using a MOSFET and a protection diode, actuating them is as simple as sending a digital high from your microcontroller of choice.

We’ve seen solenoids used to play a vibrophone before, but those were commercial units. Making your own hardware is far more hardcore.

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