A Robotic 808 Drum Machine

If you spent the 1980s hanging out at your local record store, and you don’t have a hankering for spandex and bouffant rock-god hairstyles, the chances are you’ll have more than a few pieces of electronic music from the period in your collection. The proliferation of electronica during that era came through the arrival of relatively inexpensive mass-market digital polyphonic instruments, edging out the sounds of monophonic analog synthesisers for a subsequent generation to rediscover in a later decade. Individual instrument models became icons and entered the musical vernacular of the day, the Ensoniq Mirage sampling synthesiser, the Yamaha DX7 FM synthesiser, or the Roland TR-808 drum machine.

It is the Roland TR-808 that inspired today’s subject, the MR-808 robotic drum machine, from [Moritz Simon Geist]. A percussion sequencer featuring real instruments all built into a cabinet styled to resemble a huge Roland 808. Originally built as a performance instrument, but since reinvented as a piece of installation artwork that visitors can program for themselves.

Block diagram of the MR-808
Block diagram of the MR-808

There is a comprehensive description of the machine’s design and build on the creator’s website, as well as a more high-level introduction. A significant amount of effort was put in to creating mechanical instruments as close as possible to the Roland sounds, with each instrument being operated by solenoids driven by a MIDI-controlled Arduino Mega. A second Arduino, this time an Uno, controls lighting that follows the instruments.

The interactive part of the installation comes from a sequencer front-end running in a web browser on a Nexus 7 tablet, this appears to be served from a Raspberry Pi which supplies MIDI to the MR-808.

The results can be seen in the video below the break, and judging by the reaction of the audience the machine is rather popular.

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Upgrading Old Synths To OLED

Roland’s Alpha Juno 2 is an analog, polyphonic synth made in the mid-80s. While it isn’t as capable as the massive synths made around that time, it was very influential synth for the techno scenes of the late 80s and early 90s.

[Jeroen] is lucky enough to have one of these synths, but like all equipment of this era, it’s showing its age. He wanted to replace the character LCD in his Alpha Juno 2 with an OLED display. The original character LCD was compatible with the Hitachi HD44780 protocol, and still today OLEDs can speak this format. What should have been an easy mod turned into editing hex values on the EEPROM, but he still got it to work.

While the original character LCD could display one line of 16 characters, the ROM in the synth didn’t know this. Instead, the display was organized as a 2×8 display in software, with line one starting at address 0h, and line two starting at 40h. For a drop-in replacement, [Jeroen] would need a display the characters organized in this weird 2×8 format. None exist, but he does have a hex editor and an EEPROM burner.

With the Alpha Juno’s firmware in hand thanks to someone who does a few firmware hacks to this synth, [Jeroen] had everything he needed. All that was left to do was going through the code and replace all the references to the second line of the character LCD.

After burning and installing the new ROM, the OLED display was a drop-in replacement. That meant getting rid of the whiney EL backlight in the original display, and making everything nice and glowy for a few nights on a dark stage.

Turning your CNC into a Vinyl Cutter

This may seem like a no-brainer, but it’s actually pretty easy to modify your CNC machine to hold a vinyl cutter blade in order to do stencils or even cut out vinyl logos!

[Jouni] designed a holder for a standard Roland vinyl/sticker cutter blade (replacement with 5 blades is about $10 on eBay). It’s made to fit his specific CNC which uses a 65mm spindle, with a 49mm mounting ring — but the file could be easily modified to suit others.

Simply clamp your plastic or vinyl onto a flat piece of wood, and get stenciling! [Jouni’s] included his .STL file on his site in case anyone wants to try it out. While he’s designed it for 3D printing, you could probably CNC mill it as well — which would kinda make more sense…

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Digitally Controlled Circuit Bending

Circuit bending doesn’t get a lot of respect around some parts of the Internet we frequent, but there is certainly an artistry to it. Case in point is the most incredible circuit bending we’ve ever seen. Yes, it’s soldering wires to seemingly random points on a PCB, but these bend points are digitally controlled, allowing a drum machine to transform between bent crunchiness and a classic 1980s drum machine with just a few presses of a touch screen controller.

All circuit bending must begin with an interesting piece of equipment and for this project, [Charles], the creator of this masterpiece of circuit bending, is using a Roland TR-626, a slightly more modern version of the TR-606, the percussive counterpart of the infamous TB-303. The circuit is bent in the classical fashion – tying signals on the PCB to ground, VCC, or other signals on the board. [Charles] then out does everyone else by connecting these wires to 384 analog switches controlled by an Arduino Mega. Also on the Arduino is a touch screen, and with a slick UI, this old drum machine can be bent digitally, no vast array of toggle switches required.

[Charles] has put up a few videos going over the construction, capabilities, and sound of this touch screen, circuit bent drum machine. It’s an amazing piece of work, and something that raises the bar for every circuit bending mod from this point on.

Thanks [oxygen_addiction] and [Kroaton] for sending this one in.

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Roland 808 synced to MIDI

Reading this week’s ATtiny-themed builds, [Thomas] was reminded one of his coolest builds. His midi808 project used an ATtiny2313 to sync a vintage Roland 808 drum machine to his Logic workstation.

Even though MIDI had been around for a few years when 808s were being made, the CPU in the 808 isn’t exactly up to the task of handling MIDI. Instead, the 808 used an interface known as DIN Sync that was designed to keep 808s, 707s, and 303s in time with each other. MIDI to DIN Sync boxes do did exist, but even the auxiliary equipment to use an 808 is getting hard to find.

The build takes a MIDI signal and passes it through an opto-isolator per the MIDI spec. The microcontroller reads the MIDI signal and passes it out through the DIN Sync port. The DIN Sync protocol is only 24 pulses per quarter note output with TTL voltages, and the project code is easy enough to follow. It’s a nice build for one of the greatest drum machines ever made. Listen to a track [Thomas] made with his new setup after the break.

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Javascript drum machine


[Cameron Adams] recently appeared on a panel about JavaScript libraries. He represented the hard working coder that still wrote everything from scratch. He wanted to make something mindblowing for the audience. He ended up creating the JS-909 drum machine entirely in javascript without relying on libraries or flash. While he makes no claims of compatibility, it certainly is a nice bit of kit.

[via Waxy]

TB-303 teardown

Flickr member and owner of awesome stuff [Firegroove] brought us a teardown of a Roland TR-909 drum machine before, and now he brings us a new photoset of a TB-303 synth teardown. The machines comprise two thirds of the holy trinity of 80’s electronic music machines, so look after the break for more photos.

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