Body Controller

Arduino firmware for the R2-D2 body expander. Controls servo-driven doors and utility arms, LED panel animations, audio/vocalizer integration, and battery monitoring — all coordinated over I2C and serial.

Hardware

• Microcontroller: Arduino Pro Mini (16MHz, ATmega328P)
• Servos (6): Left door, right door, top utility arm, bottom utility arm, CBI door, data panel door
• LED Drivers: 2× MAX7219/MAX7221 chips (SPI) driving the Charge Bay Interface (CBI) and Data Panel displays
• Audio: HCR Vocalizer (external Teensy 4.1 + Audio Shield) via serial
• Power: 24V system with analog voltage divider on A3 for battery monitoring
• Switches: CBI on/off (pin 8), Data Panel on/off (pin 9), Volt Meter on/off (pin 14)
• Communication: I2C (address 9) + hardware serial at 9600 baud

Project Structure

src/
  CMB_Body_Expander_1_7.ino   Main firmware
  config.h                     Pin assignments, servo positions/speeds, timing constants
lib/
  VarSpeedServo/               Variable-speed async servo control
  LedControl/                  MAX7219/MAX7221 LED matrix driver
  HumanCyborgRelationsAPI/     HCR Vocalizer audio + emotion API

Building

This project uses PlatformIO. Target board is pro16MHzatmega328.

pio run          # build
pio run -t upload  # upload to board

Serial Command Interface

Commands are sent over serial in the format BD:COMMAND\n at 9600 baud.

Command	Description
RESET	Close all doors/arms, reset vocalizer
OPENALL	Open all doors and utility arms
DOORS	Toggle all four doors
UARMS	Toggle both utility arms
TOPARM / BOTARM	Toggle individual utility arms
LDOOR / RDOOR	Toggle left/right front doors
CBIDOOR / DATADOOR	Toggle CBI / Data Panel doors
CBIDATADOOR	Toggle CBI and Data Panel doors together
LEIA	Play Leia message with full body sequence
VADER	Play Imperial March sequence
THEME	Play Star Wars theme sequence
CANTINA	Play Cantina Band sequence
SCREAM	Dramatic scream sequence (servos + lights + audio)
HELLO	Play hello audio
HAPPY / HAPPY2	Happy emotion (moderate / strong)
SAD / SAD2	Sad emotion
MAD / MAD2	Mad emotion
SCARED / SCARED2	Scared emotion
OVERLOAD	Overload sequence
VOL	Cycle volume (High → Low → Mute)

Configuration

All tunable parameters are in src/config.h:

• Servo pin assignments and open/close positions (in microseconds)
• Servo movement speeds (0–255)
• LED animation timing constants
• Battery voltage thresholds (green/yellow/red)
• I2C address and peer device addresses
• HCR Vocalizer volume levels per channel
• Conditional compile flags: DEBUG, TEST, LEGACY, monitorVCC, BLUELEDTRACKGRAPH