Add quadrotor flight control demo project

user/tasks/examples/quadrotor.c

@@ -0,0 +1,68 @@
+#include <fcntl.h>
+#include <math.h>
+#include <stdio.h>
+#include <task.h>
+#include <tenok.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "madgwick_filter.h"
+
+#define deg_to_rad(angle) (angle * M_PI / 180.0)
+#define rad_to_deg(radian) (radian * 180.0 / M_PI)
+
+madgwick_t madgwick_ahrs;
+
+void quat_to_euler(float *q, float *rpy)
+{
+    rpy[0] = atan2(2.0 * (q[0] * q[1] + q[2] * q[3]),
+                   1.0 - 2.0 * (q[1] * q[1] + q[2] * q[2]));
+    rpy[1] = asin(2.0 * (q[0] * q[2] - q[3] * q[1]));
+    rpy[2] = atan2(2.0 * (q[0] * q[3] + q[1] * q[2]),
+                   1.0 - 2.0 * (q[2] * q[2] + q[3] * q[3]));
+
+    rpy[0] = rad_to_deg(rpy[0]);
+    rpy[1] = rad_to_deg(rpy[1]);
+    rpy[2] = rad_to_deg(rpy[2]);
+}
+
+void flight_control_task(void)
+{
+    setprogname("flight control");
+
+    madgwick_init(&madgwick_ahrs, 400, 0.13);
+
+    int accel_fd = open("/dev/accel0", 0);
+    int gyro_fd = open("/dev/gyro0", 0);
+
+    if (accel_fd || gyro_fd) {
+        printf("failed to open the IMU.\n\r");
+        exit(1);
+    }
+
+    float rpy[3];
+    float accel[3], gravity[3];
+    float gyro[3], gyro_rad[3];
+
+    while (1) {
+        /* Read accelerometer */
+        read(accel_fd, accel, sizeof(float[3]));
+        gravity[0] = -accel[0];
+        gravity[1] = -accel[1];
+        gravity[2] = -accel[2];
+
+        /* Read gyroscope */
+        read(gyro_fd, gyro, sizeof(float[3]));
+        gyro_rad[0] = deg_to_rad(gyro[0]);
+        gyro_rad[1] = deg_to_rad(gyro[1]);
+        gyro_rad[2] = deg_to_rad(gyro[2]);
+
+        /* Run orientation estimation */
+        madgwick_imu_ahrs(&madgwick_ahrs, gravity, gyro_rad);
+        quat_to_euler(madgwick_ahrs.q, rpy);
+
+        usleep(2500);
+    }
+}
+
+HOOK_USER_TASK(flight_control_task, 3 /*THREAD_PRIORITY_MAX*/, 2048);

user/tasks/tasks.mk

@@ -11,6 +11,10 @@ SRC += $(PROJ_ROOT)/user/tasks/shell_task.c
 #SRC += $(PROJ_ROOT)/user/tasks/debug_task.c # Run `scripts/download-examples.sh` first
 SRC += $(PROJ_ROOT)/user/tasks/mavlink_task.c
 
+# Demo projects
+SRC += $(PROJ_ROOT)/user/tasks/examples/quadrotor.c
+
+# Examples
 #SRC += $(PROJ_ROOT)/user/tasks/examples/fifo-ex.c
 #SRC += $(PROJ_ROOT)/user/tasks/examples/mqueue-ex.c
 #SRC += $(PROJ_ROOT)/user/tasks/examples/semaphore.c