Open source
PedalScope is a measurement instrument, and an instrument is only worth trusting if it can be checked. Three things make that possible, and all three are published under open licences: the plans for the Reference Box, a fixture whose distortion was computed before it was built, and the Breakout Box that sits in the measurement loop beside it; the methods documents, which describe every measurement and ship with code that reproduces it; and the measurement libraries, real devices measured under stated conditions. They all live in one public repository, PhaseDog/pedalscope-open-source. The app itself is not open source.
Hardware
Build plans for the project's two bench fixtures, each with its schematics, build plan, bill of materials, photos and a revision-stamped ZIP, under the CERN Open Hardware Licence, permissive variant (CERN-OHL-P-2.0).
- The Reference Box — six small circuits whose distortion was computed from resistor arithmetic and Fourier theory before the box was built. The published Reference Box library was measured with it.
- The Breakout Box — a small passive box for the measurement loop: a probe point, a 10 kΩ series source on demand, and a straight pass-through for null runs.
The methods documents
Two documents, built from the app's own measurement code on every change and never edited by hand, served at /methods/:
| Technical reference | methods.pdf — for a reader who wants the method itself: for each measurement, the stimulus, the analysis step by step, every parameter with its value, and a parity check against an independent reimplementation. |
|---|---|
| Explained | explained.pdf — the plain-language companion, chapter for chapter, for a reader who plays and wants to know what the charts mean. |
| In the repository | methods/ — the LaTeX sources, the Python reimplementation of every method, the figures with the values they plot, and the manifest every quoted number comes from. |
| Licences | The code is MIT; the documents, figures and generated material are CC BY 4.0. |
What runs on its own: in a fresh checkout the generated fragments and every figure but one regenerate byte-identical to what is committed, and both PDFs build from the committed inputs alone. The parity tests cannot run there — they call the private Swift tool that runs the app's own analysis beside the Python's — and are published as the record of what is asserted and at what tolerance.
The measurement libraries
Real devices, measured under stated conditions and exported from the shipping build exactly as measured, free to download and open in PedalScope. The index, with the arithmetic each set was checked against, is the Library page. Each set is CC BY 4.0.
The PedalScope name and mark are not part of any of these grants. Building the box, reproducing a method or redistributing a library does not make the result a PedalScope product, and none of the licences above conveys a right to the name.