02_request_datastream.ino

void request_datastream() {
  //Request Data from Pixhawk
  uint8_t _system_id = 255;       // id of computer which is sending the command (ground control software has id of 255)
  uint8_t _component_id = 2;      // seems like it can be any # except the number of what Pixhawk sys_id is
  uint8_t _target_system = 1;     // Id # of Pixhawk (should be 1)
  uint8_t _target_component = 0;  // Target component, 0 = all (seems to work with 0 or 1)
  uint8_t _req_stream_id = MAV_DATA_STREAM_ALL;
  uint16_t _req_message_rate = 0x01;  //number of times per second to request the data in hex
  uint8_t _start_stop = 1;            // 1 = start, 0 = stop

  // Initialize the required buffers
  mavlink_message_t msg;
  uint8_t buf[MAVLINK_MAX_PACKET_LEN];

  // Pack the message
  mavlink_msg_request_data_stream_pack(_system_id, _component_id, &msg, _target_system, _target_component, _req_stream_id, _req_message_rate, _start_stop);
  uint16_t len = mavlink_msg_to_send_buffer(buf, &msg);  // Send the message (.write sends as bytes)

  Serial1.write(buf, len);  //Write data to serial port
}