Communication Protocol

Protocol

The protocol has the following requirements:

• motor commands
• configuration commands for peripherals
• raw sensor data
• computed sensor data
• Peripheral control commands (Lights, claws, etc)
• semi-autonomous commands
• emergency alerts (leak in hull, pressure to high, overheating, etc.)

Format

Each packet will have have a header, and then the data.

Transmitted Packet
TCP
Neptune Header
Neptune data
TCP

Header

Field	Type	Purpose
Packet Type	unsigned byte	Essentially an enumeration for the types described above
Priority	unsigned byte	How quickly should the receiver be handling this
Sequence	unsigned byte	potentially necessary for order is we use udp instead of tcp

Control Packets

Speed Motor - set a specific motor to a speed and direction.

Field	Type	Purpose
Motor ID	unsigned byte	The specific motor to run
Direction	bool	true=forward false=reverse
Speed	float	The raw speed to set (0.0-1.0)
Duration	int	How many cycles to stay at the speed

Position Motor - move a motor to a specific position; most useful for servo's and steppers.

Field	Type	Purpose
Motor ID	unsigned byte	The motor to run
Degree	float	Amount of rotation, can be in degree's or Radians depending on motor config. Can be more than a full rotation for multiple rotations, and negative for reverse.
Speed	float	the raw speed to set (0.0-1.0)

Relay control - turn a peripheral on or off, such as lights, claws, and valves.

Field	Type	Purpose
Relay ID	unsigned byte
Enable	bool

Request Peripheral Status - requests a property from a peripheral, such as a motors speed, a lights status, or a sensor value.

Field	Type	Purpose
Peripheral type	unsigned byte	motor, light, servo, claw, limit switch
Peripheral ID	unsigned byte	which specific one
Property ID	unsigned byte	enabled, speed, position, triggered

Data Packets

Sensor data

Field	Type	Purpose
Sensor Type	int
Sensor ID	int
Data	char*

Computed Data

Field	Type	Purpose
Data Type	int
Data	char*

Peripheral Status

Field	Type	Purpose
Peripheral type	unsigned byte	motor, light, servo, claw, limit switch
Peripheral ID	unsigned byte
Property ID	unsigned byte	enabled, speed, position, triggered
Data	char*	responsibility of the other side to parse into a struct

Alerts

Field	Type	Purpose
Alert Type	int	Error, interrupt, hardware malfunction?
Threat Level	int	how serious is it?
Subsystem	int	Is it software, motors, main board, power?
ID	int	Specific part of the subsystem (motor ID, sensor ID, IC, etc)

Emulator

The device emulator will essentially be a c++ program that connects to the host application and sends and receives data via tcp over the device protocol. It will most likely not include camera functionality, but should be able to emulate all of the other functions. It could also potentially be used as a unit testing platform.