https://github.com/aleh/noisechip
Turns an ATtiny85 into a "noise chip" suitable for an analogue drum machine such as LDB-1.
https://github.com/aleh/noisechip
analog attiny85 drum-machine noise-generator
Last synced: 2 months ago
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Turns an ATtiny85 into a "noise chip" suitable for an analogue drum machine such as LDB-1.
- Host: GitHub
- URL: https://github.com/aleh/noisechip
- Owner: aleh
- License: mit
- Created: 2018-04-08T12:35:47.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2022-04-27T19:56:44.000Z (over 3 years ago)
- Last Synced: 2025-05-07T05:30:33.806Z (5 months ago)
- Topics: analog, attiny85, drum-machine, noise-generator
- Language: C++
- Homepage:
- Size: 5.86 KB
- Stars: 21
- Watchers: 1
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# NoiseChip
Turns an ATtiny85 into a "noise chip" suitable for an analogue drum machine such as
[LDB-1](http://mickeydelp.com/blog/anatomy-of-a-drum-machine).
One of the pins outputs digital "white" noise using a linear feedback shift register,
4 other pins output different square waves out of tune with each other.
The noise is used by the snare drum, clap and hi-hat modules, while sqaure waves are
used to add a bit of metallic tembre for the hi-hat.
Note that the frequencies of the square waves are not described in the article,
but there is a reference to a schematics of Boss DR-110 where each of these square
wave modules is made using 2 inverters with a 4.7nF capacitor being charged via
82K, 120K, 330K, and 220K resistors. My crude calculation shows that the corresponding
frequencies are: 1049Hz, 717Hz, 261Hz, 392Hz.
Measuring the actual frequncies out of the ATtiny85 you get the following (hat tip to @zumdar):
- Pin 0: 960 Hz
- Pin 1: 673.5 Hz
- Pin 2: 248 Hz
- Pin 4: 369 Hz
- Pin 5: Noise