Over 4 years since Larry Cotton’s “player marimba” was featured in Make and subsequently retrofitted for MIDI using MD24 MIDI decoders, the instrument is still going strong. Larry recently updated the drive circuitry, replacing the original relays with NPN Darlington transistors to drive the mallet solenoids. Video of the marimba in action can be found here and here.
My MIDI Marimba (which uses 2 of your MD-24′s) is 90% refurbed.
The MD24′s work perfectly, and are more than capable of triggering the TIP-120′s, a vast improvement over relays, etc.
I also added RCA plugs and jacks to the mallets, for easy servicing and assembly/disassembly.
The first pic shows early stages of the new wiring. The power supply’s pretty beefy for the solenoids, with adjustable output around 12V, and 5V for the MD24′s.
The second pic was taken just before all the wires were stuffed in and the plexiglass cover installed.
The third pic shows it all buttoned up. That’s an iRig Keys keyboard on the floor, and an ancient Gateway laptop running Cakewalk software. I’m also using an M-Audio Uno to deliver MIDI to the MD24′s.
The wonderful little iRig Keys allows the marimba to be recorded and played manually. Kids love it.
The picture below shows an initial test of the MD24 and TIP120 driving one of the marimba’s solenoids. Video here.
Chicago-based artist Alexander DeGraaf employs several UMR2 and MSA-T boards for his ongoing project Pastel Fractal. Alex uses MIDI control for robotics and live audience participation in addition to more traditional sequencing and synthesis functions.
I have three sampling keyboards into which I have installed UMRs: two Yamaha VSS-30s and one Casio SK-8. I use different samples on the keyboards for different compositions such as: my singing voice, a dog bark (sampled from SK-5), a TR-808 clap, a Doc Watson banjo riff, a Chet Atkins guitar riff, and some scatting sounds.
In my installation sculptures, I’ve used as many as two MSA-T MIDI Decoders to turn my MIDI note messages into voltage pulses for as many as fourteen small 24V solenoid motors. I’ve engineered these motors to reset immediately after being triggered, and I’ve connected them in various ways to percussive elements within the sculptures. In this way, I am able to MIDI-sequence robotic percussion strikes and sounds in sync with my compositions that are otherwise played by more conventional MIDI sound engines such as synthesizers, keyboards, and drum machines. The robotic percussive elements within the sculpture each provide a unique source from which sounds stimulate the inhabitant of the sculpture. I provide additional sound sources – besides robotic percussions and the main P.A. – by attaching small speakers to individual keyboards and drum machines so they may be hung around the sculpture or handed out to the inhabitants to pass and move about. Thus, inhabitants of the sculpture – also known as members of the audience – can contribute to the composition during a performance with these floating pieces of hardware by engaging buttons or keys within their reach.
John Erik King, the sole instrumentalist of Disappearing Cowboy, has created the “Minimalist Organic Tech” stage rig, an integrated system that includes guitar effects and amplification, bass, synthesis, vocal processing, and robot drums. Scripted MIDI messaging provides “scene” control, freeing King to simultaneously perform live guitar, bass, and synth.
ride cymbal, two actuators to account for the high volume of repetitive patterns typically played on cymbals.
toms, two actuators, again to account for quarter/sixteenth note repetition.
crash, one actuator with a very long throw to really smack the crash cymbal so it stands out.
bass, mute, and distortion control. (big muff)
guitar, Moog LP ladder filter into an eventide stereo digital delay. The stereo output then goes to two different amps with independent mutes.
synth, only one string goes to a Roland GR-30, which has its own mute as well.
has three outputs. Bass, guitar, and synth.
tuning E (bass string), E,B,E,B,E. (five other strings)
top three strings are attached to a modified Bigsby tremolo which creates a relative detune effect.
Because everything is controlled by MIDI, we can shift scenes and tempos for each song, or even in between songs. The vocal delays and guitar delays are in perfect sync with the tempo which the drums precisely adhere to. If the tempo is at 135, everything is locked at 135.
I originally controlled everything with a laptop, but found a karaoke device that plays back MIDI files to use instead.
All the different scenes and transitions are triggered automatically. And the entire set is set up like a playlist. We hit one button and the entire show plays without any foot controllers or input like that of any kind. It’s all automated, with the exception of playing the instrument, of course.
The rig employs two Highly Liquid MSA-P MIDI decoders to trigger drums, route audio signals, switch amplification channels and control effects. An MPA MIDI decoder is used to automate control of the Moog ladder filter.
Tim Laursen combined a power supply, drum machine, mixer, MSA-R MIDI decoder, Darlington drivers, and a collection of individually miked, solenoid-actuated drums. The result is “Double Rainbow”, a complete mobile robot drum system.