Make a Capacitive Clothespin Keyboard for Your iPad

Even with all the optimization and style of new technology, the keyboard is a difficult thing to replace. Touch screens just don’t deliver the tactile feedback that connects us to the medium. [Adam Kumpf] remedies this by building his own keyboard interface to work with an iPad piano app, all from craft materials you’d likely find lying around in the kitchen.

To make your own, you’d first need a bunch of clothespins which will ultimately act as your keys. [Adam] shows how to stitch the separated halves of the clothespins onto a piece of cardboard with some basic rubber bands. These tension the keys so that they can rock back and forth over a pen or pencil placed beneath them. When you press down on one end, the other lifts causing an opposing pin to press the corresponding key of the iPad, just like a hammer inside a piano. With a little aluminum foil for conductivity wrapped around the side making contact, you’ve got yourself a quick solution for your itch to rock some Chopin.

You can see how well the project works in action below in his video:

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Capacitive Garage Door Opener Hides Behind Your Dash

[Pyrow] wanted to upgrade his garage door opener remote. It worked just fine, but changing those tiny batteries out can be an inconvenience. Plus, the remote control was taking up valuable storage space and would always rattle around while driving. [Pyrow] decided to make use of an Omron E2K-F10MC2 capacitive touch sensor to fix these issues.

[Pyrow's] circuit still makes use of the original remote control. He just added some of his own components to get it to do what he wanted. The circuit is powered by the car’s battery, so it never needs a battery replacement. The circuit is protected with a fuse and the power is regulated to prevent electrical spikes from burning up the original remote control. The actual circuit is pretty simple and uses mostly discrete components. It’s all soldered onto proto board to keep it together. He only had to solder to three places on the original remote control in order to provide power and simulate a button press.

Next, [Pyrow] took his dash apart. He used double-sided tape to attach the touch sensor to the back of the dash.  After securing the electronics in place with tape, he now has a working hidden garage door opener. Full schematics are available in the writeup linked above. Also, be sure to watch the demonstration video below.

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An Automated Flappy Bird Player

game Flappy Bird has been ported to just about every system imaginable, including but not limited to the Apple II, Commodores, pretty much every version of the Atari, and serves as a really great demonstration of the TI-99′s graphics capabilities. Porting is one thing, but having a computer automate Flappy Bird is another thing entirely. [Ankur], [Sai], and [Ackerly] in [Dr. Bruce Land]‘s advanced microcontroller design class at Cornell have done just that. They’re playing Flappy Bird with a camera, FPGA, and a penny wired up to a GPIO pin to guide the little 8-bit-bird through Mario pipes.

The setup the team is using consists of a webcam that records the screen of a smartphone, an FPGA, and a little bit of circuitry to emulate screen taps. Inside the FPGA, the team is looking at the video stream from the phone to detect the bird, pipes, and gaps. The ‘tapper’ unit is a US penny, placed right above the ‘tap’ button, wired to a GPIO port. This was found to be the ideal contact for a capacitive touch screen – taps that were too small weren’t registered, and taps that were too big registered as two taps.

For spending an entire semester on automating Flappy Bird, the team has a lot of knowledge to show for it, but not the high score: the bird only makes it through the first pipe 10% of the time, and the second pipe 1% of the time. The high score is three. That’s alright – getting the algorithm right to play the game correctly was very, very difficult, and to nail that problem down, they estimate it would take at least another semester.

Kyub MIDI Keyboard Puts a Piano in Your Pocket

[Keith Baxter] loves making electronic instruments. His latest vision has come to life as Kyub, an open-source MIDI keyboard. [Keith] has previously graced our site and cracked Popular Science with his servoelectric guitar.

[Keith] wanted to make a completely open source instrument that’s elegant, useful, and a bit more accessible than the servoelectric guitar, so he teamed up with a hacker/electronic music expert and an industrial designer. He built the early prototypes around an Arduino Uno. The current iteration uses a Teensy 2.0 and is available in various forms through Kickstarter. [Keith] opened the Kyub up to crowd funding in an effort to obtain volume pricing on some of the parts as well as an Eagle license to make the PCB files available commercially.

The Kyub has eleven pressure-sensitive capacitive keypads on five sides of the cube. The accelerometer can be used to vary note volume, bend the pitch, or whatever else you program it to do. Of course, you’ll need a computer with a synthesizer program, but [Keith] says it is compatible with most software synth programs, some of which are free.

There’s a demo video of an early prototype after the break. Videos of the Kyub in its current form are available on the Kickstarter page.

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Mug Music Is Good to the Last Drop

[Bonnie] is majoring in CS at Princeton and minoring in Awesome. She is taking an electronic music class and had to produce a digital instrument for her midterm project. She and her friend [Harvest] came up with Mug Music, which turns a ceramic mug of water into an instrument.

The circuit is very easy to replicate with an Arduino, a coil, and a few resistors and capacitors. [Bonnie] wanted to experiment with Disney Research Lab’s Touché method of touch detection, and Mug Music is based on this Touché for Arduino Instructable. The inputs are turned into MIDI notes with ChucK, a real-time sound synthesis language developed at Princeton.

As you may have guessed and will see in the demonstration video after the jump, you aren’t limited to touching the water. The entire mug will produce sounds as well. [Bonnie] says you can trigger a thunderclap if you touch the water and a grounded surface simultaneously.

This would be a great project to explore with kids, especially as a music therapy vehicle for kids on the autism spectrum. It isn’t as physical as these portable musical stairs, but it may draw less attention from lawyers.

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The Nickelphone

nickelphone

[Tyler Bletsch] sent us a tip about his new build: a keyboard that redefines “coin-operated.” The Nickelphone can emit square wave tones via a piezo buzzer, but [Tyler] made this 25-key piano as a MIDI keyboard capable of driving a full synthesizer.

He chose an ATMega644 as the brain because it’s Arduino-friendly but has more data pins—32—than the usual ATMega328 chip, which allows him to provide each key with its own pin. Each coin was soldered to its own wire and connects up to a 1MΩ resistor array. Coin-presses are recognized by the simple capacitive sensing technique outlined here, but [Tyler] needed to take advantage of a workaround to accurately detect multiple presses.

Check out [Tyler's] detailed project guide for more information as well as the source code. Check out the video of the Nickelphone after the break, then browse through some other capacitive touch hacks, like the Capacitive Touch Business Card or the Capacitive Touch Game Controller.

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Making capacitive touch sensors with pencil and paper

capacitive-touch-sensor

There are few things more frustrating than being in the middle of working on a project and realizing that you are missing some crucial component that ties the whole thing together. According to Murphy’s Law, this sort of thing will only happen when parts are completely impossible to procure.

If you’re ever hunting for a touch sensor but can’t get your hands on one, [Alan Chatham’s] tutorial on simple DIY capacitive touch sensors might be just what you need to keep things moving along.

[Alan’s] sensors rely on the conductive properties of graphite, which is easily found in just about any pencil on the market. The sensors are created by simply drawing on a piece of paper with a pencil, then wiring the images or text up to your favorite microcontroller via some paperclips and a couple of resistors.

Paper and pencil might not make for the most durable means of input, but we’re pretty sure that [Alan’s] capacitive touch sensors would be very helpful in a pinch. He doesn’t have video of the sensors in action just yet, though he says he’ll put something together here shortly.