Why Engineering Is Harder Than It Looks | Shop Talk #86

Why put a microcontroller in the trunk instead of simply tapping into the brake lights or turn signals?

In this episode of Shop Talk, Dave and Glen dig into the hidden trade-offs behind Dave’s Mark III RGB lighting project: reading outputs instead of inputs, handling hazard lights and reverse lights, burned-out bulbs, unexpected states, wiring, waterproofing, optocouplers, LEDs, ESP32s, schematics, Gerber files, and the difference between a quick solution and a robust one.

They also follow up on software optimization, AI-assisted programming, assembly-level code, compilers, C variable arguments, and whether modern hardware prices might finally make optimization matter again.

Plus: CAN bus projects, Knight Rider lights, a PDP-11 controller, time machines, Bunnyhugs, and other important engineering questions.

Questions from viewers on Dave’s Garage and Shop Talk.

00:00 - Hey I’m Dave…

00:34 - Why put the controller in the trunk?

03:05 - Why not just tap the brake and flasher circuits?

03:51 - Why avoid CAN and LIN bus projects?

05:36 - How does it handle burned-out bulbs?

06:52 - What happens with four-way flashers?

07:30 - Hazards and rapid turn-signal changes

08:07 - Hazards, reverse lights, and braking

09:21 - How does the strip behave in hazard mode?

10:21 - What happens if the controller reboots mid-drive?

11:09 - Will water collect behind the LED strip?

12:03 - Which LEDs did you use, and how are they mounted?

13:19 - How do the optocouplers protect factory wiring?

13:59 - Which LED strip and ESP32 should builders use?

15:34 - Can you share the schematic?

15:55 - How did you make the LED-system diagram?

16:23 - Are there certification rules for vehicle lighting?

18:33 - How did you route the wiring to the strip?

19:16 - Will you release the PCB design files?

19:56 - Will the controller board be available to buy?

20:45 - When does production start?

21:16 - Can AI optimize code at the assembly level?

21:53 - Did BBT support position-independent code?

23:01 - Do programmers use optional stops like CNC?

23:41 - Is programming becoming an AI-assisted profession?

24:29 - When did Microsoft start optimizing software?

25:52 - How are C variable arguments parsed?

26:37 - Why did programming languages become more human-readable?

28:22 - What is LNC 460?

28:42 - Why not use a PDP-11 as the controller?

29:40 - Why are rebuilt carburetors worse now?

30:40 - Why is there a case of oil in the trunk?

31:11 - Did this car come from an Alabama auction?

31:26 - How does the car handle unleaded fuel and synthetic oil?

32:16 - Why not add a Knight Rider light effect?

32:33 - Is “turn signaling” a Canadian thing?

32:53 - Could the emergency mode be triggered remotely?

33:24 - Why is the high-mounted brake light so low?

33:40 - Could brake-light brightness reflect braking force?

35:10 - Why not add an orange warning mode?

35:34 - Can Dave’s Garage make a Bunnyhug?

37:30 - End of show shenanigans

42:23 - The Friendly Coder…