This page provides information to add a custom payload to the H520.
Hardware integration involves retrofitting and securing the custom payload onto the top plate of the gimbal, which includes the airframe connectors for the serial communication to the autopilot and power/ground. The hardware components required are:
- H520 airframe
- Custom payload (robotic arm, cameras, etc.)
The pinout diagram can be found below.
VCC is the output from the drone battery (15.2V normal, 17.4V max) with a max current of 1.5A, for a total of 22W power.
Software integration involves processing the MAVLink messages received on the serial line from the H520 flight controller (FC), which is based on PX4. The FC supports most of the core MAVLink commands including camera triggering and gimbal control. Since the Wifi module is integrated into Yuneec payloads, there is no easy way to send custom data or telemetry to the ground control station (DataPilot or Mobile SDK), without significant engineering work to rebuild the data link.
You can interface to the pins and receive MAVLink messages. The serial communication is 8N1 at 500,000 baud rate.
- Refer MAVLink headers from MAVLink.
- Information about MAVLink commands supported can be found in Supported-MAVLink-Messages and MAVLink-Specs
- To trigger the camera, the camera needs to listen for the command: MAV_CMD_IMAGE_START_CAPTURE
- To orient the gimbal, use this command: MAV_CMD_DO_MOUNT_CONTROL
To bind RC, you either need to send the bind command with param1 = 1, param2 = 0. Or alternatively, you can flip the H520 upside down. If it is in bind mode, the LEDs will flash yellow.
Yuneec payloads such as the E90 and E50 cameras have the Wi-fi module built-in. If your payload does not include a Wi-fi AP with MAVLink forwarding, then you will not be able to connect to a ground station. You can opt to use this Wi-fi module for a complete data link, but your custom payload will need to be triggered by an external system.
> 1. On each camera trigger, I will get the MAV_CMD_IMAGE_START_CAPTURE message.
Correct, you trigger when you receive this message and you can check the params in the MAVLink docs. Also, you're only supposed to respond to commands addressed to MAV_COMP_ID_CAMERA (100).
You are supposed to acknowledge commands using COMMAND_ACK.
> 2. What about CAMERA_IMAGE_CAPTURED, when I get this message from H520?
You, as a camera, are supposed to send this when an image has been captured for proper status reporting.