Hull Controller API Reference

I2C Interface Specifications

• Slave Address: 0x08
• Communication Protocol: I2C

Command Structure

Each command consists of:

1. Command byte (identifying the action)
2. Data byte (parameter for the action)

Command Codes

Command	Hex Value	Description	Data Parameter	Response
CMD_TURRET_ROTATE	0x10	Controls turret rotation	0-200 (-100 to +100 speed, centered at 100)	None
CMD_TURRET_ELEVATE	0x11	Controls turret elevation	0-200 (-100 to +100 speed, centered at 100)	None
CMD_TRACKS_MOVE	0x20	Controls forward/backward movement	0-200 (-100 to +100 speed, centered at 100)	None
CMD_TRACKS_TURN	0x21	Controls left/right turning	0-200 (-100 to +100 turn rate, centered at 100)	None
CMD_LASER_TOGGLE	0x30	Controls laser targeting system	0=OFF, 1=ON	None
CMD_IR_TOGGLE	0x31	Controls IR emitter	0=OFF, 1=ON	None
CMD_CANNON_FIRE	0x32	Fires cannon	0-255 (max firing duration in ms)	None
CMD_FRONT_LIGHTS	0x40	Controls front lights	0=OFF, 1=ON, 2=BLINKING	None
CMD_REAR_LIGHTS	0x41	Controls rear lights	0=OFF, 1=ON, 2=BLINKING	None
CMD_TURRET_LIGHT	0x42	Controls turret light	0=OFF, 1=ON	None
CMD_GET_BATTERY	0xE0	Requests battery voltage	None	2 bytes (uint16_t millivolts)
CMD_GET_POSITION	0xE1	Requests position data	None	4 bytes (2x uint16_t coordinates)
CMD_GET_CANNON_STATUS	0xE2	Requests cannon ready status	None	1 byte (0=not ready, 1=ready)
CMD_GET_GPS	0xE3	Requests GPS coordinates	None	8 bytes (4x uint16_t GPS data)
CMD_GET_ALL_SENSORS	0xEF	Requests all sensor data	None	16 bytes (combined sensor data)
CMD_GET_STATUS	0xF0	Requests general status	None	1 byte (status bits)

Status Byte Structure (CMD_GET_STATUS response)

Bit	Description	Value
0	Cannon ready	0=not ready, 1=ready
1	Laser status	0=OFF, 1=ON
2	IR emitter status	0=OFF, 1=ON
3	Front lights status	0=OFF, 1=ON or BLINKING
4	Rear lights status	0=OFF, 1=ON or BLINKING
5-7	Reserved	Always 0

All Sensors Data Structure (CMD_GET_ALL_SENSORS response)

Bytes	Description	Type
0-1	Battery voltage	uint16_t (millivolts)
2-5	Position data	2x uint16_t (x, y coordinates)
6	Cannon status	uint8_t (0=not ready, 1=ready)
7	Front lights state	uint8_t (0=OFF, 1=ON, 2=BLINKING)
8	Rear lights state	uint8_t (0=OFF, 1=ON, 2=BLINKING)
9-15	Reserved	Always 0

Examples

Moving Forward at Half Speed

Command: 0x20
Data: 150 (100 + 50 = half speed forward)

Turning Right at 30% Rate

Command: 0x21
Data: 130 (100 + 30 = 30% right turn)

Firing Cannon with 200ms Safety Timeout

Command: 0x32
Data: 200 (200ms max firing duration)
Response: None, but subsequent CMD_GET_CANNON_STATUS will return 0 until cooldown period ends

Getting Battery Voltage

Command: 0xE0
Data: None
Response: Two bytes representing millivolts (e.g., 0x70, 0x12 = 0x1270 = 4720mV = 4.72V)