August 2016 7
David Byrne also gets into mechanical sound creation with his “Playing The Building” installation. An old organ is equiped with electronics and pneumatics so that the organ-keys can be used to control motors, solenoids and pneumatic parts.
On Musical Robots and Robotic Musicians: Gil Weinberg at TEDxPeachtree 2012
The HiHat machine is part of the Drum Robot MR-808. It took some experiments until I figured out how this can be crafted into a high-performance working instrument: A HiHat is normally used in any track and plays most of the time!
This robotic HiHat is based on a normal drummers hihat, with two cymbals and parts of the hihat-stand. It also contains two solenoids (electro magnets), one for opening and closing the cymbals, on for the actual beating of the cymbal.
The force needed to open the HiHat is quite high, as it has to work against the force that closes the HiHat. The solenoid used here comes from a car engine starter. They have the most powerful solenoids, are reasonably cheap, easy to get at any car junk jard (or eBay) and operate at 12V. Perfect for low budget robotics!
The disadvantage is, that they consume roughly between 30 and 50A. Un-technically spoken: This is very much! I use server power supplies which can supply a current up tp 50A@ 12V.
I started with a standard HiHat machine (the full hardware Hihat Stand) and cut the lower part off. One thing you have to consider: a HiHat is default-OPEN, meaning that the spring inside keeps the cymbals separated when no pressure is applied. Only if the drummer steps on the foot-part, the HiHat closes. Replacing the drummers-foot with a solenoid (yeeha!) would mean that you would have a constantly powered solenoid, in this case about 35A, for most of the time (closed HiHat).
As we don’t want to fry eggs with the robot (solenoids can get quite hot) its recommended to reverse this mechanics, meaning that the HiHat is default-closed, and the solenoid is only powered when you want an open HiHat. I then removed the spring and let the gravity do the closing of the cymbals. Afterward I attached a fan inside the HiHat machine as the solenoid gets really hot for off-beat disco music. The huge car solenoid is only for the opening and closing of the hihat.
The actually beater is another solenoid which just hammers directly on the lower cymbal. It is used for both closed and open HiHat.
Josh also build the keys himself. Whoho!
The operational principle is that when stepper motors are back-driven, they induce a pseudo-sinusoidal alternating current. If this signal is amplified and connected to a speaker, you can listen to it as sound. The pitch of the sound is determined by the frequency of the wave, which depends on how fast the motor is back-driven. Higher speed will be a higher note. I thought this sound was interesting, so I wanted to make an instrument that used this mechanism to make music. This is an experimental instrument I built that uses back-driven stepper motors to synthesize sound.There are 49 stepper motors, one for each note in my four octave instrument. At rest, each motor floats above one of 49 disks, which increase in size exponentially as the notes ascend in pitch. The disks spin together, driven by a single speed-controlled DC motor. When a key is pressed, the corresponding stepper motor is engaged with the corresponding disk in the disk stack, and the disk back-drives the stepper motor.
Wooden Organ Built Around Stepper Motors to Create a Unique Synthesized Sound
I’m a big fan of Simplify 3D. Its a commercial software but its worth every 149$ that it costs. If you digging deeper into 3D-Printing you can take your pre-processing to the next level. I had the issue, that when printing a model with solid infill (100%) and 0.1mm layer height on an Makerbot Replicator 2 the base would show gaps in between the extrusion lines.
As the model should be water tight I made a simply test – blowing through the model. It was not watertight, you could blow “through” the wall. Holding it against the light you could also see that there were gaps in between the extrusion lines.
One thing with Simplify 3D is that you have a lot of parameters, which also interact from time to time and sometimes its unclear what change bring the solution.
I fiddled with a lot of parameters, including extrusion width, gap fill or infill extrusion width. What helped was to tweak the parameter “Extrusion multiplier” to 1.10 (formally 0.8). Like this I can make really solid model with out gaps of holes between the extrusion lines.
German artists and craftsman build this amazing mechanical sequencer whoch has one (!) constantly running rotary unit as a actor.
Watch this 20 minute documentary (german only) about his amazing and friendly hardware hacker:
This university project led by Charles Matthews works on the connection of classic traditional serial composition – in this case gamelan music – and robotic Gamelan instruments. The actuators are driven electronically. Charles also developed a software called “Pipilan” which was written in Max/MSP. With this he controls the gamelan Gongs. From our understanding the software is an intelligent system which lets users interact with the robotic instruments by entering single set of notes. These are than merged into a constant gamela-music like flow.
The Augmented Gamelan project was set up to explore the combination of gamelan and electroacoustic music, with a focus on the way the instruments are traditionally played. The sound of this percussion ensemble from Indonesia is broken down, extended and warped through custom software and speakers placed amongst – and sometimes attached to – the instruments. The repertoire is based on traditional material and may be played in a wide range configurations to adapt to the space and context of performance. Many pieces also use traditional vocals including macapat (Javanese sung poetry).