Noisey chips

Preamble

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

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ADSR waveform generator

Preamble

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

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

Preamble

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.

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555 Noisemusick kit

Preamble

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.

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