Hardware In The Loop - A proof of concept

Weekend project to see how far I can push a quick-and-dirty thrust vectoring loop: PC runs a 1 kHz 2D rocket sim, the ESP32 pretends to be the flight computer and outputs back a tilt command.

What you get

• PC side: physics step + serial link at 921600 baud.
• ESP32 side: proportional controller that nudges the rocket from -5 deg to +5 deg over ~30 seconds.
• Metrics are printed so you can watch the loop behave.

Fast setup

1. Plug in an ESP32 dev board.
2. Flash the firmware in src/main.cpp using PlatformIO.
3. Build the PC sim on Windows with scripts\build_pc.bat (uses cl.exe).
4. Run rocket_sim.exe; it should auto-find the board and start communicating.

How the link talks

• PC sends: I,seq,velocity,angle once per physics tick.
• ESP32 replies: A,tilt.
• Baud: 921600. If your cable/port flakes out, drop it in pc/src/rocket_sim.cpp and platformio.ini to match.

Quick notes

• Tested on random ESP32 dev kits with USB serial.
• If prints stutter, close other serial monitors or try a lower baud.
• The physics is intentionally lightweight so timing is the thing we measure, not frame rate.