Using MIDI and Magnets to Produce Tones with Tines

Normally you’d expect the sound of a pipe organ to come from something gigantic. [Matthew Steinke] managed to squeeze all of that rich melodic depth into an acoustic device the size of a toaster (YouTube link) which uses electromagnetism to create its familiar sound.

[Matthew ’s] instrument has a series of thin vertical tines, each coupled with a small MIDI controlled electromagnet. As the magnet pulses with modulation at a specific frequency, the pull and release of the tine causes it to resonate continuously with a particular tone. The Tine Organ is capable of producing 20 chromatic notes in full polyphony starting in middle C and can be used as an attachment to a standard keyboard or a synthesizer app on a smart phone. The classic style body of the instrument is made out of mahogany and babinga and houses the soundboard as well as the mini microcontroller responsible for receiving the MIDI and regulating the software oscillators sending voltage to the magnets.

[Matthew’s] creation is as interesting to look at as it is to listen to, so I’d recommend checking out the video below to hear the awesome sound it produces:

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Solar Powered Circuit Waters Your Plants


If you want your plants to stay healthy, you need to make sure they stay watered. [Dimbit] decided to build his own solar powered circuit to help automatically keep his plants healthy. Like many things, there is more than one way to skin this cat. [Dimbit] had seen other similar projects before, but he wanted to make his smarter than the average watering project. He also wanted it to use very little energy.

[Dimbit] first tackled the power supply. He suspected he wouldn’t need much more than 5V for his project. He was able to build his own solar power supply by using four off-the-shelf solar garden lamps. These lamps each have their own low quality solar panel and AAA NiMH cell. [Dimbit] designed and 3D printed his own plastic stand to hold all of the solar cells in place. All of the cells and batteries are connected in series to increase the voltage.

Next [Dimbit] needed an electronically controllable water valve. He looked around but was unable to find anything readily available that would work with very little energy. He tried all different combinations of custom parts and off-the-shelf parts but just couldn’t make something with a perfect seal. The solution came from an unlikely source.

One day, when [Dimbit] ran out of laundry detergent, he noticed that the detergent bottle cap had a perfect hole that should be sealable with a steel ball bearing. He then designed his own electromagnet using a bolt, some magnet wire, and a custom 3D printed housing. This all fit together with the detergent cap to make a functional low power water valve.

The actual circuit runs on a Microchip PIC microcontroller. The system is designed to sleep for approximately nine minutes at a time. After the sleep cycle, it wakes up and tests a probe that sits in the soil. If the resistance is low enough, the PIC knows that the plants need water. It then opens the custom valve to release about two teaspoons of water from a gravity-fed system. After a few cycles, even very dry soil can reach the correct moisture level. Be sure to watch the video of the functioning system below. Continue reading “Solar Powered Circuit Waters Your Plants”

Electro-permanent magnets for quadcopters


Imagine a quadcopter hovering above a payload – a can of beans, perhaps. The ‘copter descends onto the payload, activates an electromagnet, and flies away with a hobo’s dinner. Right now, this is a bit of an impossibility. A normal electromagnet that powerful would consume an amazing amount of power, something quads don’t usually have in abundance. With the OpenGrab project, the dream of a remote-controlled skycrane is within reach, thanks to some very clever applications of magnetics.

The tech behind the OpenGrab is an electro-permanent magnet, basically an electromagnet you can turn on and off, but doesn’t require any power to stay on. OpenGrab was heavily influenced by a PhD thesis aimed at using these devices for self-assembling buildings.

This project had a very successful Kickstarter campaign and has seen some great progress in the project. While beer doesn’t come in steel cans anymore, we can imagine a whole lot of really cool applications for this tech from infuriating electronic puzzles to some very cool remote sensing applications.

Prototyping a Maglev train using LEGO


Serious research using not-so-serious equipment? We don’t know about that. What’s wrong with using LEGO as a research platform for a Maglev? This team has been doing so for quite some time and with great results.

A Maglev is a vehicle based on the principles of magnetic levitation. Similar poles of magnets repel each other and this concept can be used to create a friction-less track system. But this raises the problems of braking and locomotion. The build log linked above covers the conception in what is the eighth iteration of the research project. But the video below offers the most concise explanation of their approach to these issues.

The researchers are using magnets positioned in trench of the track as a kind of magnetic gear to push against. A series of electromagnets on the Lego vehicle ride in that track. The can be energized, working as a linear motor to push against those permanent magnets. But how do you know which direction of travel this will cause? That problem was solved by adding a hall effect sensor between each electromagnet. Before switching on the coil the hall effect sensors are polled and a timing scheme is selected based on their value. This is used to push the train up to speed, as well as slow it down for braking.

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Arduino boards control cheap clockworks via coil injection

Here’s a couple of clocks that use Arduino boards to control inexpensive clockworks. The concept is quite simple, and perhaps best outlined by [Matt Mets’] article on the subject. As it turns out, these clockworks are driven by a coil, forming a device that is quite similar to a stepper motor. If you solder a wire onto each end of the electromagnetic coil and hook those to a microcontroller, you can alter the speed at which the clock ticks. Just drive one pin high and the other low, then reverse the polarity for the next tick.

The clock you see on the right (translated) is a store-bought cheapy. The Arduino barely visible at the bottom of the image is sending pulses once every second. But as you can see in the video after the break, holding down a button will fast-forward through time. [Sodanam] posted his code as well as pictures of the hardware hack itself.

To the left is a horse of a different color. It’s a clock modeled after the Weasley household clock from the Harry Potter books. The clockwork trick is the same, but the Arduino uses GPS data and NOAA weather information to set the status.

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Clap to remove this brassiere

Like some strange manga come to life, you can remove this brassiere with a clap of your hands. Under the red bow is a not-so-small mechanical clasp that replaces the original on the strapless front-clasping undergarment. We hate to criticize, but [Randofo] really went off the deep end of hardware overkill on this project. The clasp itself is the electromagnetic coil removed from the case of a mechanical relay. An ATmega168 listens for a spike in sound pressure from a microphone, then drives the relay to release the feminine support system.

It is Valentine’s day. The question being is this romantic or sleazy? Watch the NSFW video after the break and let us know your opinion in the comments.

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Universal credit card in the palm of your hand


Do you remember the magnetic card spoofer in Terminator 2? It was a bit farfetched because apparently the device could be swiped through a reader and magically come up with working account numbers and pin numbers. We’re getting close to that kind of magic with [Jaroslaw’s] card spoofer that is button-programmable.

Building off of a project that allows spoofing via an iPod and electromagnet, [Jaroslaw] wanted something that doesn’t require a computer to put together the card code. He accomplished this by interfacing a 16-button keyboard and a character LCD with an AVR ATmega168 microcontroller. Card codes can be entered with the buttons and verified on the LCD. Of course this is still dependent on you knowing the code in the first place.

As you know, credit cards use this technology. We don’t think Walmart is going to be OK with you pulling this out in the checkout line, not to mention local five-oh. This technology is also used for building access in Universities, businesses, and hotels. If used in conjunction with some other spy technology you’ll be on your way to becoming a secret-agent-man.