Making Music With Clojure And Bananas

April 27, 2015 by Eric Evenchick 12 Comments

At this point, the banana piano is a pretty classic hack. The banana becomes a cheap, colorful touch sensor, which looks sort of like a piano key. The Arduino sets the pin as a low-level output, then sets the pin as an input with a pull up resistor. The time it takes for the pin to flip from a 0 to a 1 determines if the sensor is touched.

[Stian] took a new approach to the banana piano by hooking it up to Clojure and Overtone. Clojure is a dialect of Lisp which runs in the Java Virtual Machine. Overtone is a Clojure library that provides tons of utilities for music making.

Overtone acts as a client to the Supercollider synthesis server. Supercollider has been around since 1996, and provides a wide array of sound synthesis functions. Overtone simply tells Supercollider what to do, letting you easily program sounds in Clojure.

The banana piano acts as an input to a Clojure program. This program maps the banana to a musical note, then triggers a note on Overtone’s built-in piano sampler. The result is a nice piano sound played with fruit. Of course, since Overtone and Supercollider are very flexible, this could be used for something much more complex.

After the break, a video of the banana piano playing some “Swedish Jazz.”

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Slick Six-Voice Synth For AVRs

April 27, 2015 by Elliot Williams 26 Comments

He started off making an AVR synthesized guitar, but [Erix] ended up with much more: a complete six-voice AVR wavetable synthesis song machine that’ll run on an ATMega328 — for instance, on an Arduino Uno.

If you’re an AVR coder, or interested in direct-digital synthesis or PWM audio output, you should have a look at his code (zip file). If you’d just like to use the chip to make some tunes, have a gander at the video below the break.

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An Introduction To Individually Addressable LED Matrices

April 26, 2015 by Brian Benchoff 8 Comments

The most fascinating project you can build is something with a bunch of blinky hypnotic LEDs, and the easiest way to build this is with a bunch of individually addressable RGB LEDs. [Ole] has a great introduction to driving RGB LED matrices using only five data pins on a microcontroller.

The one thing that is most often forgotten in a project involving gigantic matrices of RGB LEDs is how to mount them. The enclosure for these LEDs should probably be light and non-conductive. If you’re really clever, each individual LED should be in a light-proof box with a translucent cover on it. [Ole] isn’t doing that here; this matrix is just a bit of wood with some WS2812s glued down to it.

To drive the LEDs, [Ole] is using an Arduino. Even though the WS2812s are individually addressable and only one data pin is needed, [Ole] is using five individual data lines for this matrix. It works okay, and the entire setup can be changed at some point in the future. It’s still a great introduction to individually addressable LED matrices.

If you’d like to see what can be done with a whole bunch of individually addressable LEDs, here’s the FLED that will probably be at our LA meetup in two weeks. There are some crazy engineering challenges and several pounds of solder in the FLED. For the writeup on that, here you go.

ASCII Art With Pure Data And A Typewriter

April 21, 2015 by Brian Benchoff 19 Comments

[vtol] is quickly becoming our favorite technological artist. Just a few weeks ago he graced us with a Game Boy Camera gun, complete with the classic Game Boy printer. Now, he’s somehow managed to create even lower resolution images with a modified typewriter that produces ASCII art images.

As with everything dealing with typewriters, machine selection is key. [vtol] is using a Brother SX-4000 typewriter for this build, a neat little daisy wheel machine that’s somehow still being made today. The typewriter is controlled by an Arduino Mega that captures an image from a camera, converts it to ASCII art with Pure Data and MAX/MSP, then slowly (and loudly) prints it on a piece of paper one character at a time.

The ASCII art typewriter was recently shown at the 101 Festival where a number of people stood in front of a camera and slowly watched a portrait assemble itself out of individual characters. Check out the video of the exhibit below.

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Switch Mains Power With An ESP8266

April 19, 2015 by Bryan Cockfield 93 Comments

Before we begin, we must begin with an obligatory disclaimer: handling mains voltage can be very dangerous. Do not do so unless you are qualified! You could burn your house down. (Without the lemons.) That being said, [TJ] has created an interesting dev board for controlling mains voltage over WiFi with the now-ubiquitous ESP8266 module. At only 50mm x 25mm, it is easily small enough to fit inside a junction box!

Called the MPSMv2, the core of the project is the ESP8266 module. The dev board itself can support anything with GPIO pins, whether it’s an Arudino, Raspberry Pi, or anything else with those features. Flashing the NodeMCU firmware is pretty much all that needs to be done in order to get the device up and running, and once you get the device connected to your WiFi you’ll be able to control whatever appliances you want.

The device uses a triac to do the switching, and is optically isolated from mains. Be sure to check out the video after the break to see the device in action. All in all, this could be a great way to get started with home automation, or maybe just do something simple like build a timer for your floor lamp. Anything is possible!

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Play Robotic Bongos Using Your Household Plants

April 16, 2015 by Theodora Fabio 2 Comments

[Kirk Kaiser] isn’t afraid to admit his latest project a bit strange, being a plant-controlled set of robotic bongos. We don’t find it odd at all. This is the kind of thing we love to see. His project’s origins began a month ago after taking a class at NYC Resistor about creating music from robotic instruments. Inspired to make his own, [Kirk] repurposed a neighbor’s old wooden dish rack to serve as a mount for solenoids that, when triggered, strike a couple of plastic cowbells or bongo drums.

A Raspberry Pi was originally used to interface the solenoids with a computer or MIDI keyboard, but after frying it, he went with a Teensy LC instead and never looked back. Taking advantage of the Teensy’s MIDI features, [Kirk] programmed a specific note to trigger each solenoid. When he realized that the Teensy also had capacitive touch sensors, he decided to get his plants in on the fun in a MaKey MaKey kind of way. Each plant is connected to the Teensy’s touchRead pins by stranded wire; the other end is stripped, covered with copper tape, and placed into the soil. When a plant’s capacitance surpasses a threshold, the respective MIDI note – and solenoid – is triggered. [Kirk] quickly discovered that hard-coding threshold values was not the best idea. Looking for large changes was a better method, as the capacitance was dramatically affected when the plant’s soil dried up. As [Kirk] stood back and admired his work, he realized there was one thing missing – lights! He hooked up an Arduino with a DMX shield and some LEDs that light up whenever a plant is touched.

We do feel a disclaimer is at hand for anyone interested in using this botanical technique: thorny varieties are ill-advised, unless you want to play a prank and make a cactus the only way to turn the bongos off!

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Arduino Vs. Arduino: The Reseller’s Conundrum

April 15, 2015 by Brian Benchoff 64 Comments

Over the last few months, the internal struggles between the various founders of Arduino have come to a head. This began last November when Arduino SRL (the Italian version of an LLC) sued Arduino LLC for trademark infringement in Massachusetts District court. To assuage the hearts and minds of the maker community, Arduino SRL said they were the real Arduino by virtue of being the first ones to manufacture Arduino boards. A fork of the Arduino IDE by Arduino SRL – simply an update to the version number – was a ploy to further cement their position as the true developers of Arduino.

This is a mess, but not just for two organizations fighting over a trademark. If you’re selling Arduinos in your web store, which Arduino do you side with?

[Nate] from Sparkfun is answering that question with a non-answer.

Currently, Arduino SRL is the only source of Arduino Unos. Sparkfun will continue to buy Unos from SRL, but they’re not necessarily siding with Arduino SRL; people demand blue Arduinos with Italy silkscreened on the board, and Sparkfun is more than happy to supply these.

There are, however, questions about the future of Arduino hardware. The Arduino software stack will surely be around in a year, but anyone that will be purchasing thousands of little blue boards over the next year is understandably nervous.

This isn’t the first time Sparkfun has faced a challenge in Arduino supply. In 2012, when the Arduino Uno R3 was released, all the documentation for their very popular Inventor’s Kit was obsoleted overnight. In response to these supply chain problems, Sparkfun created the RedBoard.

Sparkfun has always offered to pay royalties on the RedBoard to Arduino LLC, just as they do with the Arduino Pro and Pro Mini. Effectively, Sparkfun is on the fence, with offers to manufacture the Arduino Zero, Uno, Mega, and Due coming from the LLC.

The reason for this is consumers. If someone wants an Arduino SRL-manufactured board, they’ll buy it. If, however, a customer wants to support Arduino LLC, that option is on the table as well.

It’s not a pretty position to be in, but it does show how someone can support one Arduino over another. In a year or two, there will only be one Arduino, but until then, if you have a preference, at least Sparkfun is giving you a choice.

Credit to Sparkfun for the great Spy vs. Spy image. Why don’t you sell googly eyes?