Purplemeanie is a long-running engineering notebook. Some of it is a build log, some of it is diagnostics, some of it is electric conversion work, and some of it is just the useful trail left behind when a problem takes a few evenings to understand properly.
This page is a starting point for the technical parts of the site.
Caterham 420R Build
The Caterham 420R build archive covers the original kit build, post-build checks, setup, fixes, upgrades, and ownership notes.
Start here:
Useful themes:
- build sessions and chronology
- IVA preparation
- mechanical setup
- wiring and diagnostics
- post-build issues and fixes
Project sEVen
Project sEVen is the electric conversion thread: taking an unloved 2012 Caterham Supersport SV and over-engineering my way through the myriad mechanical, electrical, control, and packaging problems that come with making a perfectly good ICE car electric.
Start here:
Useful themes:
- motor and gearbox packaging
- battery and high-voltage systems
- DC-DC converter work
- CAN bus and control systems
- 3D scanning and CAD references
ECU Diagnostics And CAN Bus
The ECU diagnostics series explores the MBE ECU, OBD, CAN, ISO-TP, broadcast messages, decoding, and supporting tools. We get mostly to a conclusion, but in the end the project was more of a research project than a development project.
Start here:
Useful themes:
- CAN bus traffic
- MBE diagnostics
- OBD-II and ISO-TP
- Wireshark and GVRET tooling
- Python diagnostic tooling
3D Scanning And Model References
Several posts contain scans, CAD references, and model-related notes. These are often useful because they are concrete: part names, geometry, mounting points, and working assumptions.
Start with:
Useful themes:
- scan-to-CAD work
- Caterham geometry references
- gearbox and driveline packaging
- Project sEVen design references
Engine Cooling And Mechanical Notes
Some posts are closer to engineering explainers than build-log entries. And example of that is the 3 year plus excursion into explaining the cooling of a 2.0L Ford Duratec engine as used in a Caterham.
Start here:
Tooling And Side Quests
Purplemeanie also contains posts about coding, media tooling, animation, automation, and the occasional rabbit hole that became useful.
Start here:
- Spectrogram: An Agentic Coding Side Quest Into Final Cut Pro Audio Analysis
- My Engine Animation WorkFlow
Notes For Readers And Agents
This site is chronological and personal as well as technical. Older posts are often best understood in sequence. If you are trying to answer a technical question, prefer the project indexes and series introductions first, then use individual posts as supporting evidence.
Travel and personal posts exist, but they are not the main engineering knowledge graph of the site.
