Modular Drum Machine Creates Random Rhythms

July 9, 2016 by Bryan Cockfield 6 Comments

Don’t worry, the rhythms themselves aren’t random! That would hardly make for a useful drum machine. [kbob]’s creation does have the ability to randomly generate functional rhythms, though, and it’s all done on a breadboard.

The core of this tiny drum machine is two Teensy dev boards. One is an FM synth tuned to sound like drums, and the other is a random rhythm generator with several controls. The algorithms are from Mutable Instruments’ open source Eurorack modules. The entire thing fits on a breadboard with JIGMOD modules for the user interface. The machine runs on lithium batteries in the form of USB cell phone chargers. The battery holders were designed in Fusion 360 and 3D printed.

The function of the drum machine is pretty interesting as well. There are a set of triggers tied to the buttons on the machine. When a button is pressed, the drum machine plays that sound at the appropriate time, ensuring there are no offbeat beats. The potentiometers are polled once every millisecond and the program updates the output as required. There’s also a “grid” of rhythms that are controlled with two other knobs (one to map the X coordinate and the other for the Y) and a “chaos” button which adds an element of randomness to this mapping.

The modular nature of this project would make this a great instrument to add to one’s musical repertoire.It’s easily customizable, and could fit in with any of a number of other synthesizer instruments.

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Organize That Messy Prototype

September 20, 2015 by Rud Merriam 35 Comments

You’re working away busily at your project. A pcb here cabled to a breadboard in the middle, and over there some motors and other devices. It should work but it doesn’t. Time to hook-up the multimeter but the test point is on the other side. As things are moved around to reach the point, the magic smoke escapes from a critical component. Should have put those pliers away.

Workbenches are always messy. [Ryan Clark] may have an idea that can help. His Jigmod system — currently running a kickstarter campaign — uses ~~an acrylic~~ a polycarbonate sheet with a grid of mounting holes to keep prototyping hardware in place. If you need to move the prototype around there is no strain on the wiring and no way to set a circuit down on that pair of pliers. The positioning of everything is your decision.

[Ryan] is also providing breakout type boards for connectors like USB and Ethernet, switches, battery holders, and other typical components. This is one place where the system really shines. A lot of these interface connectors tend to be breadboard-unfriendly and the terminal blocks these modules offer solves those issues. When you need to demonstrate your project it’s easy to transport since everything is attached to the plate. No more disconnecting cables, especially jumper wires, and hoping you get them all hooked back the right way at the destination.

With so many dev boards out there we really enjoy seeing jigs that can hold them along with a breadboard. This Stickvise-inspired 3D printed jig sticks out in our minds as a favorite. Do you have your own system of organizing your prototype builds? We’d love to hear about it in the comments!