https://github.com/noracodes/fives

555 timer module for VCVRack
https://github.com/noracodes/fives

Last synced: over 1 year ago
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555 timer module for VCVRack

• Host: GitHub
• URL: https://github.com/noracodes/fives
• Owner: NoraCodes
• Created: 2020-04-20T03:20:47.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2020-05-02T19:19:03.000Z (about 6 years ago)
• Last Synced: 2025-03-30T16:46:28.498Z (over 1 year ago)
• Language: C++
• Size: 463 KB
• Stars: 8
• Watchers: 4
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
# Fives

## VCVRack modules by NoraCodes

**Fives** is a collection of modules based on the specified physical operation of the

world's most popular integrated circuit: the **LM555 multimode timer**.

![The Fives Astable and Fives Astable C next to each other.](res/lineup.png)

### Why 555?

The 555 isn't generally used as an oscillator in modular instruments because, while it can

easily run in astable mode and generate a clean square wave with a variable duty cycle,

varying the frequency without changing the duty cycle requires a variable

capacitor, which are expensive and hard to integrate.

There is, of course, no such limitation in the world of VCVRack; variable caps are free and

never break down, and voltage-controlled variable capacitors are just as easy.

So, Fives provides modules that closely model what a real 555-based module would look like

as well as modules that apply the power of CV and impossibly accurate and fast variable

capacitors to the same mathematical model.

### Fives Astable

Fives Astable is a low-frequency oscillator and clock generator based on a

physical model of the LM555 timer chip in an astable configuration.

It has two knobs - ON and OFF - which control the high and low time of the oscillator,

and a RESET input which, when above 5 volts, kills the output.

![Two Fives Astable modules, one resetting the other.](res/astable-sample.png)

The total period of oscillation is the on time plus the off time; there is no single

frequency control. It can oscillate as quickly as 9 Hz and as slowly as 0.1Hz

(once every 10 seconds) with a duty cycle around 66%.

The UNI/BI toggle transposes the waveform from 0v to 10v (default) to -5v to 5v (BI mode).

### Fives Astable C

The Fives Astable C is a voltage-controlled audio-rate oscillator which extends the slimmer,

simpler Fives Astable with a variable capacitor and CV inputs for the ON, OFF, and PERIOD inputs.

The added PERIOD variable capacitor allows the Fives Astable C to oscillate as quickly as 2.6 kHz

or as slowly as 26 Hz, with a duty cycle as low as 56.5%.

It is tuned to take 1V/Oct input on the PERIOD input by default, with all parameter knobs at 33.3%.

Modifying any of the parameters will detune the module, but that can be fun too.

![A Fives Astable C and a Fives Astable, showing the use of the PERIOD parameter.](res/astable-c-sample.png)

CV applied to the inputs are scaled by the knob parameters.