After watching The Gigatron TTL Computer without a Microprocessor, I got to thinking about building an Apple I (or II). After a quick search I found the Wikipedia entry for the Replica 1 (see this Apple 1 kit page), and from there the Apple II section of ReactiveMicro’s site, and the apple-ii-rev-0 board.
Then I came across loads of retro teardowns from EEVblog…
Continue reading Retro!
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 (specifically ATmega48P/88P/168P/328P but the code should compile for most Arduinos).
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
Sound generators based on CD40106 Hex Inverter Schmitt triggers…
Continue reading CD40106 Synths and Oscillators
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)
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 (rather than an astable followed by a monostable, which is what the APC is).
It is also available as an iOS app, source code is available on github:Noisemusick.
Continue reading 555 Noisemusick kit
This blog started life as a section within the blog Banging noises…, until it grew too big. It deals with oscillators.
Of particular interest are Voltage Controlled Oscillators (VCO), that can be controlled by a sequencer, or other external source, for sound wave generation, of variable frequency.
Continue reading Swingers