Noisey chips


Following on from Banging noises…, I attempted to recreate the Noise Chip (U4) depicted in the LDB-1 schematic, from the article Anatomy of a drum machine. The noise chip creates both a white noise signal as well as four tuned square waves at different (unknown) frequencies. I have attempted to contact the author for more details but have not had a reply as yet.

It is using either PIC (which is likely seeing as the author states a preference for the PIC microcontrollers), or an ATtiny.  I will attempt to use a ATtiny/ATmega microcontroller.

Note that parts of this are a work in progress.

Note: The phase-correct 50% trick is possible with Timer0 on an ATtiny85, but it is not clear if it is possible with Timer1 (although Timer0 does have two channels). Atmel AVR ATtiny comparison chart

Continue reading Noisey chips


ADSR waveform generator


Too rushed for an amusing title…

Here are a number of ADSR circuits, taken from the fantastic Yusynth website (which I came across after reading StackExchange – Building a synthesizer with no prior experience) – in particular the Archives page.

The circuits are described within PDFs, and I drew up the corresponding schematic and board files in EagleCAD.

The EagleCAD files available on github, although seeing as Micro$oft have just acquired Github, they may not be there for very long… Five minutes later – #movingtogitlab!

The EagleCAD files available on Gitlab: Testkins/ADSR-Waveform-generator

Continue reading ADSR waveform generator

Messrs. Schmitt, Trigger and APC (and other stories)


Just for the hell of it, I wondered if it was possible to substitute the 555 timers in an Atari Punk Console (APC) with some other component, or components.

After seeing some Schmitt-trigger inverters (CD40106) used in oscillator circuits, see Swingers, I thought that I would come up with an alternative design.

Continue reading Messrs. Schmitt, Trigger and APC (and other stories)

555 Noisemusick kit


A friend of mine sent me details of the 555 Noisemusick kit, which, while it looks like an Atari Punk Console (APC) – see Atari Punx… -it is essentially two astable multivibrators, with the first providing a CV input to the second, and with additional IR sensors and touch pads.

It is also available as an iOS app, source code is available on github:Noisemusick.

Continue reading 555 Noisemusick kit