CAIBI project benchmark: Control Surface MIDI
Prompt version 1.0

Help me build Control Surface MIDI using the existing creator project at https://github.com/tttapa/Control-Surface. This is a CAIBI benchmark adaptation of the project build brief, not a claim about how the creator used AI.

Project context:
- Use the eight-potentiometer Leonardo/74HC4051 Getting Started route: https://tttapa.github.io/Control-Surface/Doxygen/d5/d7d/md_pages_Getting-Started.html. Keep the specified eight-potentiometer circuit and board as the baseline.
- Eight physical potentiometers connected through a multiplexer to a USB MIDI-capable board, controlling parameters in host music software.
- Build context: Arduino Leonardo with headers as the fixed reference board for this route; Eight potentiometers and one 74HC4051 analog multiplexer; Breadboard or soldered wiring, USB data cable and a compatible host; A separately designed enclosure, knobs and fixings for a permanent build.
- Fabrication scope: The maintained tutorial defines an electrical prototype, not a universal enclosure or cutting list. Measure your chosen pots, knobs, board and connectors before creating a dimensioned panel. The project benchmark uses this prototype as its starting point; an enclosure remains a design task.
- AI role: AI can generate mappings and explain the library, help design a panel and diagnose compilation errors. Board transport support, electrical connections and usable control feel remain physical checks.
- Known limitation: The library supports several boards and transports, but those combinations are not interchangeable. No physical build or universal enclosure has been validated by CAIBI.

Read the source first. Use its published design, files, dimensions and parts as the baseline; do not redesign it unless a missing detail requires a clearly labelled proposal. If you cannot access a source or verify a revision, say so.

Provide one practical build package:
1. Design and files: explain the source design, link the original editable files, and identify missing files or modifications.
2. Parts and fabrication: give quantities, exact variants and compatibility, plus a cutting or printing list where applicable. Preserve source dimensions; flag anything unconfirmed.
3. UK and US purchasing: direct product links, checked dates, stock, pack sizes, taxes, delivery and regional costs. Mark unverifiable details as unknown; do not invent links, prices or availability.
4. Assembly: an ordered guide covering fabrication, fitting, wiring or software as applicable, setup, checks and troubleshooting.
5. Cost and time: separate parts, fabrication, delivery, hands-on time and machine time, with assumptions and exclusions.
6. Function and ease: a test plan for the project's stated purpose, likely difficulties, required skills and any corrections or limitations.

Keep source facts, your proposals and items needing physical verification distinct. An estimate is not a measured build result. Do not claim to have built or tested hardware. Include failed attempts and omissions. If a section does not apply, say why.

Use the source as accessed during this run and record its revision or access date. The prompt is fixed; the linked source can change.