A 3-axis accelerometer and 3-axis gyroscope that measure the vehicle's acceleration, roll, pitch, and yaw.
A 3-axis accelerometer and 3-axis gyroscope that measure the vehicle's acceleration, roll, pitch, and yaw.
A pressure sensor that measures the vehicle's altitude.
### Processor and Memory
| 32-bit ARM Cortex-M4 Processor | A high-performance processor that runs the autopilot software. |
| 2MB Flash Memory | Stores the autopilot software and configuration data. |
| 128KB RAM | Provides fast access to data and programs. |
### Communication Interfaces
A serial communication interface for connecting to serial devices, such as GPS modules and telemetry radios.
| I2C | A two-wire interface for connecting to I2C devices, such as sensors and peripherals. |
A four-wire interface for connecting to SPI devices, such as flash memory and sensors.
Six analog input channels for connecting to analog sensors, such as voltage and current sensors.
### Motor Control
| 8 PWM Output Channels | Supports up to 8 motors or servos, with 4096 steps of resolution. |
Automatically mixes motor outputs for complex vehicle configurations, such as quadcopters and hexacopters.
### Safety Features
Automatically takes control of the vehicle if the autopilot system fails or loses communication with the transmitter.
Uses redundant sensors to ensure reliable operation in case of sensor failure.
### Operating Modes
The flight controller follows the pilot's inputs from the transmitter.
The flight controller stabilizes the vehicle's roll, pitch, and yaw, but allows for aerobatic maneuvers.
The flight controller maintains the vehicle's position and orientation.
The flight controller maintains the vehicle's altitude and position.
The flight controller orbits around a fixed point.
### Power Management
5V to 12V DC input voltage range.
Typically 100mA to 200mA, depending on the system configuration.
### Dimensions and Weight
36mm x 36mm x 10mm (1.42in x 1.42in x 0.39in).
Approximately 20 grams (0.71 oz).
Conclusion
The APM 2.8 Flight Controller with In-Built Compass is a powerful and feature-rich autopilot system designed for UAV and robotics applications. Its compact size, low power consumption, and high-performance processing make it an ideal choice for a wide range of applications, from small quadcopters to large industrial robots.
APM 2.8 Flight Controller with In-Built Compass DocumentationOverviewThe APM 2.8 Flight Controller with In-Built Compass is a popular open-source autopilot system designed for unmanned aerial vehicles (UAVs), drones, and model aircraft. This component is part of the ArduPilot project and features a built-in compass, which provides accurate orientation and navigation data. The APM 2.8 is a reliable and flexible flight controller suitable for a wide range of applications, from beginner quadcopters to advanced autonomous systems.Technical SpecificationsMicrocontroller: ATMEGA328P
Operating Frequency: 16 MHz
Input Voltage: 5V to 12V
Current Consumption: 50mA (typical)
Compass: Built-in, 3-axis magnetometer (HMC5883L)
Interfaces: I2C, SPI, UART, USB
Size: 36mm x 36mm x 10mmCode Examples### Example 1: Basic Drone Flight Control using APM 2.8This example demonstrates how to use the APM 2.8 Flight Controller to control a basic drone flight. The code is written in C++ and utilizes the ArduPilot libraries.```c
#include <AP_Common.h>
#include <AP_Motors.h>
#include <AP_InertialSensor.h>AP_Motors motors;
AP_InertialSensor ins;void setup() {
// Initialize motors and inertial sensor
motors.init();
ins.init();
// Set flight mode to STABILIZE
set_flight_mode(FLIGHT_MODE_STABILIZE);
}void loop() {
// Read inertial sensor data
ins.read();
// Stabilize the drone
stabilize();
// Update motor outputs
motors.update();
// Delay for 10ms
delay(10);
}void stabilize() {
// Calculate roll and pitch angles
float roll = ins.get_roll();
float pitch = ins.get_pitch();
// Calculate motor outputs based on roll and pitch
int mot1 = constrain(roll 100 + pitch 50, -1000, 1000);
int mot2 = constrain(-roll 100 + pitch 50, -1000, 1000);
int mot3 = constrain(-roll 100 - pitch 50, -1000, 1000);
int mot4 = constrain(roll 100 - pitch 50, -1000, 1000);
// Set motor outputs
motors.set_output(mot1, mot2, mot3, mot4);
}
```### Example 2: Compass-based Navigation using APM 2.8This example demonstrates how to use the built-in compass on the APM 2.8 Flight Controller to navigate a drone. The code is written in C++ and utilizes the ArduPilot libraries.```c
#include <AP_Common.h>
#include <AP_Compass.h>AP_Compass compass;void setup() {
// Initialize compass
compass.init();
// Set navigation mode to COMPASS
set_navigation_mode(NAVIGATION_MODE_COMPASS);
}void loop() {
// Read compass data
compass.read();
// Get current heading
float heading = compass.get_heading();
// Set desired heading
float target_heading = 45.0; // 45 degrees
// Calculate error between current and target heading
float error = heading - target_heading;
// Calculate motor outputs based on error
int mot1 = constrain(error 50, -1000, 1000);
int mot2 = constrain(-error 50, -1000, 1000);
int mot3 = constrain(error 50, -1000, 1000);
int mot4 = constrain(-error 50, -1000, 1000);
// Set motor outputs
motors.set_output(mot1, mot2, mot3, mot4);
// Delay for 10ms
delay(10);
}
```### Example 3: GPS-guided Waypoint Navigation using APM 2.8This example demonstrates how to use the APM 2.8 Flight Controller with GPS and compass data to navigate a drone to a series of waypoints. The code is written in C++ and utilizes the ArduPilot libraries.```c
#include <AP_Common.h>
#include <AP_GPS.h>
#include <AP_Compass.h>AP_GPS gps;
AP_Compass compass;// Define waypoints
const float waypoints[][2] = {{37.7749, -122.4194}, {37.7858, -122.4364}, {37.7963, -122.4573}};void setup() {
// Initialize GPS and compass
gps.init();
compass.init();
// Set navigation mode to GPS
set_navigation_mode(NAVIGATION_MODE_GPS);
}void loop() {
// Read GPS and compass data
gps.read();
compass.read();
// Get current location and heading
float lat = gps.get_latitude();
float lon = gps.get_longitude();
float heading = compass.get_heading();
// Calculate distance to next waypoint
float distance = distance_to_waypoint(lat, lon, waypoints[0][0], waypoints[0][1]);
// If distance is less than 10 meters, move to next waypoint
if (distance < 10.0) {
waypoints++;
}
// Calculate motor outputs based on distance and heading
int mot1 = constrain(distance 50 + heading 20, -1000, 1000);
int mot2 = constrain(-distance 50 + heading 20, -1000, 1000);
int mot3 = constrain(distance 50 - heading 20, -1000, 1000);
int mot4 = constrain(-distance 50 - heading 20, -1000, 1000);
// Set motor outputs
motors.set_output(mot1, mot2, mot3, mot4);
// Delay for 10ms
delay(10);
}float distance_to_waypoint(float lat1, float lon1, float lat2, float lon2) {
// Calculate distance between two points on the surface of the Earth
// Using Haversine formula
float dlat = radians(lat2 - lat1);
float dlon = radians(lon2 - lon1);
float a = sin(dlat/2) sin(dlat/2) + cos(radians(lat1)) cos(radians(lat2)) sin(dlon/2) sin(dlon/2);
float c = 2 atan2(sqrt(a), sqrt(1-a));
float distance = EARTH_RADIUS c;
return distance;
}
```These examples demonstrate the basic functionality of the APM 2.8 Flight Controller with In-Built Compass. The actual implementation may vary depending on the specific requirements of your project.