Digital IR Theremin

Digital IR Theremin

This Digital IR Theremin creates tones based on the distance of an object from its IR sensor. There’s no microcontroller here, since the project is part of an Introduction to Digital Electronics course. Instead, it uses a handful of comparators, transistors, AND gates, and a 555 timer to make noise.

The comparators are connected to create window comparators. This configuration will output a digital 1 if the input is between two reference voltages, and 0 if it is not. Using this, the analog output of the IR range sensor can be converted to digital values.

The 555 timer takes care of creating the output waveform. A specific resistor is switched in to the timer’s RC circuit depending on which window comparator is active. This allows for a different tone to be played depending on the distance from the IR sensor.

The result is a square wave, which has a frequency dependant on how close an object is to the IR sensor. By selecting the right resistances for each distance, the theremin can be tuned to play a specific scale.

This is a neat project for people looking to learn digital electronics, and the write up does a great job of explaining the theory. After the break, check out a video of the theremin generating some tones.

Continue reading “Digital IR Theremin”

Theremin takes the touch out of multitouch

Multitouch builds are all the rage now, so it’s not surprising someone would come up with a multi-touchless interface sooner or later. [Hanspeter] did just that; his Multi-touchless ribbon controller, a.k.a. Polymagnetophonic Theremin is multi-touch without the touch.

[Hanspeter]’s touchless ribbon controller uses an array of 24 Hall effect sensors that activate whenever a magnet mounted on a thimble is placed near a build. These sensors go to an ARM-equipped Maple Mini to record multitouch events and send them out over Ethernet.

Even though [Hanspeter] is only using his “multi-touchless ribbon sensor” as a theremin, there’s no reason why it couldn’t be put to other uses. It’s entirely possible to place several of these magnetic sensors in an array and build a real Minority Report interface where the user interacts with a computer without touching anything.

After the break is a video demo showing off how much control [Hanspeter] can get with the thimble/magnet setup. There’s also a few demo songs made with SuperCollider showing off a trio of sitar/Moog/harpsichord synths.

Continue reading “Theremin takes the touch out of multitouch”

iPhone wielding guitar adds tip of your finger or tip the instrument control

[Rob Morris] has been hard at working improving his guitar augmentation techniques. Here he’s demonstrating the use of an iPhone to control the effects while he plays. This builds on the work he shared a few years ago where he strapped a Wii remote to the body of his ax.

Just like the Wii remote, the iPhone includes an accelerometer. As you would expect the best parts of the older hack made it into this one, but the inclusion of the touch screen adds a lot more. In the clip after the break he starts by showing off the screen controlling a whammy bar functionality. But we really love the octave offset feature that comes next. This kind of sound manipulation simply can’t be done using a purely physical method (like the whammy bar can). But he’s not done yet. The demo finishes with a Theremin feature. You’ll notice he plucks a string but no sound comes out until he starts touching the screen. This turns it into an entirely different type of instrument.

The only info we have about putting this together is the list of packages he’s using:  TouchOSC, Max/Msp, and GuitarRig

Continue reading “iPhone wielding guitar adds tip of your finger or tip the instrument control”

Quick and easy Arduino-powered theremin

[Martin] sent in a great guide to a simple Arduino based theremin. It’s a very small build – just a single common IC and some passive components – and easy enough to build in an afternoon.

The theremin is based on a simple LC oscillator built around a 7400 quad NAND gate IC, a wire antenna, and a few caps and resistors. When a hand moves closer to the antenna, the frequency of the oscillator increases; when a hand moves away, the frequency decreases. On the software side, the oscillator is connected to the internal hardware counter of the Arduino. Every time there’s a change in the voltage output by the oscillator (all the time, varying slightly with the distance from a hand to the antenna), the counter increases by one. This counter is tallied up over 1/10th of a second, and the distance from the instrumentalist to the theremin can be determined. From there, it’s just outputting a frequency to a speaker.

All the code, schematics, and board layouts are available on [Martin]’s guide, and most of our readers probably have the parts to build this lying around their workbench. You can check out a video of [Martin]’s theremin in action on his guide.

Mini IR theremin

[Chris] at PyroElectro sent in a great 8-part write-up of a miniature infrared theremin.

The theremin is based on a PIC microcontroller and an infrared distance sensor.  The build log goes through the theory of operations for the IR sensor and tone generation. [Chris] definitely does a great job showing the math that went into the design.

Although this project isn’t a true theremin because it operates on light like a few other projects we’ve covered in the past, it’s easier to play because of the hard-coded notes. The build does show some promise though – he could likely expand it to use more accurate ultrasonic sensors or use, “two proximity sensors, one for treble and one for bass like an accordion.”

The theremin is usually played with both hands providing a continuous pitch and volume. This project features hard-coded, discrete notes, so we’re wondering about the possibility of implementing MIDI on this IR theremin. The original MIDIbox was based on the same microcontroller as this project, so it’s definitely a possibility.

Check out the video of the theremin in action below.

Continue reading “Mini IR theremin”

Humanoid robot listens to music, plays along on his Theremin


Researcher and YouTube user [mspetitegeek] along with her lab mate [Tatsuhiko Itohara] have been fortunate enough to spend some time working with the HRP-2 humanoid robot from Kawada Industries. Their research has seemingly been focused on using the robot to create real-time interactions with humans for entertainment purposes, at the very least.

The program they created allows the HRP-2 to listen and watch its human counterpart while he plays the guitar in order to recognize a beat pattern. Once the robot catches on, it plays along on his Theremin, matching both notes and rhythm perfectly. Since the human operator is clearly playing at a fairly relaxed pace, we are curious to see a demonstration where the robot required to match a snappier tune – it could be quite interesting.

In the meantime, we’re content to just sit back and enjoy the Mogwai-esque tones of the HRP-2 rocking the Theremin.

Keep reading to see a short video of the HRP-2 in action.

Continue reading “Humanoid robot listens to music, plays along on his Theremin”

Synapse turns your Kinect into a Dubstep theremin


[Ryan Challinor] is part of a group constructing a display for this year’s Burning Man festival that includes the Kinect, Ableton Live, and Quartz Composer. As the programming guru of the project, he was tasked with creating a method for his partners to utilize all three products via an easy to use interface.

His application is called Synapse and was inspired by videos he saw online of people controlling individual Dubstep beats or sound effects with the Kinect. Synapse allows you to map multiple effects to each limb, sending joint positions, hit events, and image depth data to both Ableton and Quartz Composer via OSC. The user interface looks fairly easy to work with, enabling musicians and artists to create awesome audio/visual displays using their bodies as instruments, in a very short period of time.

Check out the pair of videos below to see a brief walkthrough of the software interface as well as a quick video demonstration of what Synapse is capable of.

[via KinectHacks]

Continue reading “Synapse turns your Kinect into a Dubstep theremin”