Show Notes
In Shop Talk #89, Dave and Glen dig into viewer questions about CAN bus: the hidden computer network inside modern cars.
This week starts with the scarier version of the question: can the network inside your car be hacked? Viewers asked about CAN bus theft, headlight attacks, OBD dongles flooding the bus, modern security protections, and whether CAN bus has reached the point where it needs to be replaced.
From there, Dave explains how CAN works: CAN High and CAN Low, why vehicles can have multiple CAN networks, diagnostic buses, single-wire CAN, message priority, arbitration, identifiers, buffering, clocks, bit stuffing, and what happens when controllers misbehave.
We also get into practical projects and tools: ESP32 CAN bus setups, OBD-II, PIDs, sniffing vehicle traffic, reverse-engineering messages, reading unknown addresses, and whether Dave might do a follow-up project showing how to add a real feature using CAN.
Later in the episode, we branch into related networks and viewer requests, including FlexRay, Modbus, ARCNET, automotive Ethernet, Amiga, Turbo Pascal, NightDriver, AI-generated diagrams, and the difference between recreational and medical CAN bus.
Questions discussed include: • Can CAN bus be replaced? • Can thieves hack CAN through headlights? • Can an OBD dongle flood the bus? • How is modern CAN bus secured? • What are CAN High and CAN Low? • Do cars have multiple CAN buses? • Should critical systems be separated? • How does CAN arbitration work? • Who provides the CAN clock? • Is bit stuffing Manchester encoding? • How do you listen to CAN with an ESP32? • How do PIDs work? • Can you reverse-engineer unknown CAN messages? • What is FlexRay? • Was ARCNET like CAN bus? • Why was Turbo Pascal so fast? • Should Dave do a NightDriver architecture walkthrough?
Shop Talk is the weekly Q&A show from Dave’s Attic, where Dave Plummer and Glen Hodges discuss viewer questions, engineering stories, retro computing, Windows internals, software history, hardware, cars, and whatever else the comments drag into the shop.
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