All posts by Dann Green


SimSam 1.0

Unveiled at the beginner’s class at Handmade Music Austin #4, the SimSam (Simple Sampler) is a single-chip “sample-rate cruncher” that’s glitchy as all-get-out but only costs about $8-$12 in parts. It’s an effect with an input and output jack; and it’s a noise-maker since a jumper shorts the output back into the input when nothing is plugged into the input jack. We built 28 SimSams in a couple hours at the workshop.

Update: SimSam 2.0

SimSam 2.0 is an improved version that runs the same code as v1.0 (thus has the same functionality), but adds a Reset button. This button is on the left. The other two buttons are the same as SimSam v1.0. Also, on the PCB v2.0 there is a spot for a fourth button underneath the middle button. This is not used and only for testing/hacking your own firmware. Really, it will do nothing (except possibly damage the chip) if you install a button here, so don’t think about it. The code uses it as an output, low when the code is initializing and high when it’s running.
Continue reading SimSam

Handmade Music Austin #3

YouTube via EA78751
“Video from Handmade Music Austin #3, Dec. 20th 2009. At this workshop 13 people built the free project, Mini Space Rockers. After that we witnessed live electroacoustic sound by Lustigovi. And then 19 people built the upper division project, Andromeda Mk-4 Analog Bass Drum. And last there was an open jam with DIY bassline and drum machines from this workshop series, plus acid lines from a MIDIbox SID.”

Andromeda Space Rockers interactive jam

4ms Pedals and Eric Archer teamed up to present an interactive bass&beats installation at the Hope Center last night in Austin, TX. There were four stations around a table, each station had three Andromeda MK analog drum machines and one Autoanomous Bassline Generator. Each station also had four LEDacle bendy-light tentacles courtesy of Bleeplabs, which you could  shine on the photocells to sweep the filter sounds. Each device kept in time with an IR beam, and a MIDI clock ran between each board to bridge Nathan Wooster’s MIDI-IR Sync devices. It was packed!!

We’ll break it out again at the next Handmade Music Austin event Dec. 20 at the Salvage Vanguard Theater…. Maybe some more events too?

Autonomous Bassline kit

I finally finished the ABG kit! The boards are here and we’re ready to roll for the Nov 14 workshop at Handmade Music Austin…

You can purchase the kit, the PCB, or a programmed AVR chip here
Basic Demo:

What it does with default settings:

IR Sync Demo:

Handmade Music Austin

Church of the Friendly Ghost presents

Handmade Music Austin

A series of DIY electronic music workshops, with expert instructors from Bleep Labs, 4ms Pedals, and Eric Archer.


In a friendly workshop setting, we’ll present a newly-designed series of miniature electronic instruments, called Andromeda Space Rockers. No bigger than a credit card, these projects are designed for DIY’ers like you. They can be built in a couple of hours to make a working drum machine, bass generator, or micro-synthesizer. These fun little instruments love to jam together, and they do it by forming a wireless network to keep the rhythm! They react to the environment as well… for example, the drum machines‘ filter, pitch, and envelope are controlled with light-reactive photocells.

Each workshop will feature a different instrument.
The full series of kits will be available online as well (to be announced soon).


Basic classes are offered for beginners free of charge, where you can learn to solder and build an easy music project that will prepare you for Andromeda Space Rock.

Or you can skip straight to the ‘Upper Division’ and build one of the Andromeda Space Rockers instruments. Soldering equipment will be provided. To participate in the Upper Division classes you should be familiar with assembling printed circuit boards. An understanding of electronics theory is not required; just patience, hand-eye coordination, and enthusiasm for DIY music.


Of course, there will be an open jam / performance once the instruments are built. We encourage you to bring some pedals and a small amp to plug in your new synth or drum machine and participate in an exciting musical experiment. Huh? Since the Andromeda Space Rockers communicate with each other using infrared wireless, they keep the rhythm automatically – the space will be filled with synchronized sound as you tweak the tones and control the arrangement. The network supports an unlimited number of instruments; we are building a musical organism that reacts to its environment, part human and part machine, and containing the love built into it by your own hands.

Performances are FREE to attend.


All workshops are on Sundays.

4PM – 5:30 Beginner’s Workshop
6PM – 8 Upper Division instrument building class
8:30 – ? Open Jam and featured performance



October 18
November 15 (coincides with East Austin Studio Tour)
December 20


January 17
February 28
March 14
April 18


Salvage Vanguard Theatre
2803 Manor Rd
Austin, TX


Beginner’s Workshop is free. Upper Division registration is $45 and includes materials. We’re accepting workshop preregistration for Oct 18th and Nov 15th. The first 2 workshops are filling up quickly!


More RBG Button Matrix (version 1)… 24 bit color!

I finally got around to assembling one of the pcb’s I had printed up for this project, and it works!

The circuit is just an STP16 chip sinking current on 16 common cathode RBG LEDs, and three transistors selecting whether red, green, or blue is active. The 16 buttons are tied to the STP16 pins as well, and all the other sides of the buttons are tied together and run out to the header. An AVR ATtiny84 connects over the header. The AVR “brain-board” is nothing more than the AVR chip itself, plus a button I use to change modes, and an 6-pin ISP header and resistor used for re-programming the chip. Seeing as the parts count could be exactly one 14-pin chip, future version of the board should probably have the option of putting that chip on the board directly.

This approach is unique because it uses one STP16 chip to sink the LED current (like the Peggy 2) and also uses that same chip to produce the scanning that reads the buttons. Thus only 7 pins are needed on a single microcontroller to control a very long string of boards: 3 pins for the three colors, 1 pin for reading the buttons, and 3 pins for shifting bits into the STP16. This is much simpler and equally powerful approach as Sparkfun’s SPI boards, which uses an 18-pin current sink chip, and two 16-pin shift register chips, as well as 13 pins on the IC. I have yet to test how many boards can be controlled by a single microcontroller, so we’ve yet to see how my approach really measures up…

Full color (24-bit, which is 8-bit per “channel”) is possible, as seen in the video. However it’s fairly processor intensive and there’s not many free clock cycles. I’m using a software PWM, so using hardware PWM would speed things up of course.

Autonomous Bassline Generator

This is the first draft of an Autonomous Bassline Generator. The melodies are generated by a mathematical algorithm using the value of the Melody control as a seed. So it’s deterministic, not random.

An ATtiny44/84 chip generates Pulse-Width Modulated waves, into an analog resonant band-pass filter, whose frequency is modulated by a photocell. The ATtiny also is flashing an LED to the envelope of the notes, so you can either point the photocell at this LED to get cool old-skool analogue filter sounds, or point it at light/darkness in the room to control it manually. There’s Tap Tempo, as well as IR send/receive for syncing up to other devices!

Continue reading Autonomous Bassline Generator