FireWatchTower_2axis/host

Host Application

C++ application running on the LattePanda's Linux side. Handles camera acquisition, serial communication with the Arduino firmware, and MQTT-based remote control.

Dependencies

Library	Purpose
Vimba SDK	Camera control (Allied Vision / FLIR)
Eclipse Paho MQTT C/C++	MQTT client for telemetry and remote commands
OpenCV 4	Image processing and codecs
libjxl	JPEG XL image encoding
Boost	Program options, ASIO (serial), Spirit (parsing), threading

Install system packages (Debian/Ubuntu):

sudo apt install libboost-all-dev libopencv-dev libjxl-dev libpaho-mqttpp3-dev libpaho-mqtt3-dev

Vimba SDK must be installed separately from Allied Vision.

Build

mkdir build && cd build
cmake ..
make -j$(nproc)

Usage

./FireWatchTower_2axis [options]

Options:
  -h, --help          Produce help message
  -i, --init [bool]   Run gimbal endstop initialization sequence
  -s, --start [bool]  Auto-start camera acquisition on launch

Example:

./FireWatchTower_2axis --init true --start true

Serial Communication

The host communicates with the Arduino firmware over /dev/ttyACM0 at 115200 baud.

Incoming Telemetry

The firmware periodically sends motor status lines prefixed with $, semicolon-delimited:

$Xenc;Xerr;sgt_val;sgt_stat;is_moving;control_status;hdg;deviation_warn;humid;temp;fan_pwm

Parsed into motor_info struct in Serial.h.

Outgoing Commands

Single-character commands sent via serial.sendCommand():

• r — Reset motor parameters and power on
• e — Reset SGT (step goal threshold)
• q — Run endstop homing sequence
• y — Load heading calibration from EEPROM
• ud80 — Set auto-scan step length
• p — Step yaw to next position (trigger after stop)
• kd<heading> — Set target heading (guided mode)

MQTT Integration

Connects to broker at 172.16.42.1 (hardcoded; modify MQTT.cpp to change). Subscribes to two control topics and publishes status/camera events.

Subscribed Topics

Topic	Payload	Effect
GGS/FWT/<name>/ControlCode	0 or 1	Switch control mode: 0=free scan, 1=guided heading
GGS/FWT/<name>/target_HDG	Float string	Target yaw heading for guided mode

Published Topics

Topic	Payload	Description
GGS/FWT/<name>/StatusCode	Integer	Current control mode
GGS/FWT/<name>/CamEvent/RGB	—	Camera event notifications

Interactive Commands (stdin)

While running, the host accepts commands on stdin parsed by Boost.Spirit:

Command	Description
start	Start camera acquisition
stop	Stop camera acquisition
set camera <option> <value>	Set camera parameter via Vimba
set fps <value>	Change image rate (images/sec)
set motorctl <command>	Send raw command to firmware
debug	Toggle motor controller info output
exit	Shut down

Source Files

File	Purpose
FWT_host.cpp	Main entry point, CLI parsing, main loop
Camera.h / Camera.cpp	Vimba camera handler, image queue, JPEG XL encoding
MQTT.h / MQTT.cpp	Paho MQTT client wrapper, callback handling
Serial.h	Boost.ASIО serial port, telemetry parser
Parser.h	Boost.Spirit stdin command parser
timing.h	Timer utility class
Log.h	Logging utilities
JPEG_XL.h	JPEG XL encoding wrapper