terminal-oscilloscope

A terminal-based oscilloscope with CRT phosphor physics, written in Nim using illwill.

Features

• CRT boot/shutdown animations — phosphor ramp, beam sweep, vertical collapse, dot fade
• Y-T and X-Y modes — time-domain waveform or Lissajous figures
• Phosphor persistence — beam bloom, decay trails, intensity-based shading
• Half-block rendering — 2x vertical resolution using Unicode ▀▄█ characters
• Live audio capture — visualises system audio via ffmpeg/PulseAudio monitor
• Demo mode — built-in synthesised waveforms when no audio source is available

Install

Requires Nim 2.x.

git clone https://github.com/rolandnsharp/terminal-oscilloscope.git
cd terminal-oscilloscope
nimble build
./osc

Controls

Key	Action
m	Toggle Y-T / X-Y mode
+ / -	Increase / decrease gain (amplitude)
] / [	Zoom in / out time axis
g	Cycle grid: full → crosshair → off
space	Freeze display
d	Cycle demo frequency presets
q	Quit (with CRT shutdown effect)

Audio

Captures system audio automatically using ffmpeg with the PulseAudio/PipeWire monitor of your default output sink. Falls back to parec if available, or a built-in demo signal.

No extra packages needed — just ffmpeg (pre-installed on most Linux systems).

Credits

CRT turn-on/off animations inspired by AetherTune.