The MD24 is undergoing a major hardware revision. The new design features conventional MIDI I/O, USB-MIDI I/O, and higher-efficiency voltage regulation. Photos and discussion can be found at Twitter and Facebook.
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.
Highly Liquid Forum user Jim U recently completed a MIDI conversion of a Galanti Praeludium II organ console for use with Hauptwerk virtual organ software. Three MIDI CPU units generate MIDI output from manuals, stops and pedals. Four MD24 units drive various LED indicators on the console. Additional project discussion can be found at The Organ Forum.
Our favorite 3 ton, 65 horsepower, 4 cylinder, 620 gallon, 100 PSI sound module returns for a collection of Christmas carols. “The world’s loudest mobile musical instrument” uses MSA-T and MD24 MIDI decoders for valve solenoid control. More information can be found at the Horn & Whistle Discussion Forums, HL forum, and previous blog entries.
Bob Harris of Charlottesville, Virginia used two MD24 MIDI decoders and an array of 24-volt solenoids to automate the operation of the pedals on his Flentrop tracker pipe organ. Cakewalk Music Creator sequences the pedals while the human operator concentrates on the manuals, aided by an MD24-controlled LED metronome.
Requests for information about retrofitting the Boss DR-110 drum machine are increasingly common. Several Highly Liquid customers have successfully completed a MIDI retrofit using an MSA-P or MD24 MIDI decoder. Here are two forum threads with links to several projects:
Special thanks to all of the users who take the time to document their projects–the information is invaluable to the DIY community.
As always, please join the forums for technical support and project consultation.