How to use the Siyi HM30 air end

I. Principle

The HM30 is built on Siyi Technology's proprietary wireless HD video transmission technology, integrating remote control, data, and image links into one system. It features adaptive frequency band capabilities, allowing it to switch to the least interfered operating frequency band.

1.1 Component Description

1.1.1 Ground End

Ground End Interface Definition:

Ground End Data Flow:

1.1.2 Air End

Air End Interface Definition:

Air End Data Flow:

1.3.1 OLED Screen Display Function Definition

1.2 Indicator Description

1.2.1 Ground End

1.2.2 Air End

1.3 Pre-Use Instructions

1.3.1 Ground End Power On and Off

Power On: When powered off, briefly press the power button. The OLED screen will display "Press again to power on". Immediately press and hold the power button for about two seconds to power on the ground end.
Power Off: When powered on, briefly press the power button. The OLED screen will display "press again to power off". Immediately press and hold the power button for about two seconds to power off the ground end.
Charging: When used with external NP-F550/750/950 series rechargeable batteries, the HM30 ground end supports charging in the powered-off state using the factory-provided PD fast charger.
Usage Steps:
1. Use a Type-C fast charging cable to connect the HM30 ground end to the PD fast charger.
2. If the charging indicator light shows a constant red light, it indicates that charging is in progress.
3. When the charging indicator light changes to a constant green light, it indicates that charging is complete.

1.3.2 Installation Methods

Installation Method for Ground End Standard Omnidirectional Antenna:
1. The antenna SMA connector must be tightened securely;
2. The antenna should be installed vertically upward relative to the ground end control panel, keeping the flat side of the antenna always facing the aircraft. Antennas should not be stacked or crossed. Please refer to the following diagram:

Installation Method for Ground End Panel Range Extender Antenna:

1. The antenna SMA connector must be tightened securely;
   2. The panel antenna is a directional antenna with directionality. During flight, ensure the ground end panel antenna always faces the aircraft;
   3. When using Siyi's original range extender antenna, the short side of the panel antenna housing must be parallel to the ground, and the long side must be perpendicular to the ground end control panel to achieve the maximum communication distance;
   Installation Method for Air End Standard Omnidirectional Antenna:
2. The antenna SMA connector must be tightened securely;
   2. On multirotor drones, the air end standard omnidirectional antenna should be installed vertically downward relative to the aircraft body. On fixed-wing aircraft, the antenna can be installed vertically upward relative to the aircraft body. During flight, try to keep the flat side of the antenna facing the ground end;
   3. Antenna feeder routing should be kept away from ESCs, motors, and other equipment with high power current and severe electromagnetic interference;
   4. The 300mm long feeder included with the air end should not be crossed. The antenna body, feeder, and SMA connector should avoid direct contact with metal and carbon fiber components, maintaining at least a 10mm spacing;
   5. The two antennas on the air end should be placed together, with a minimum spacing of 50mm. During flight, avoid obstacles blocking communication between the aircraft and the ground end;
   6. At the connection points of the air end antenna feeder and its connectors, do not pull forcefully or bend excessively, as this may damage the antenna. When adjusting antenna angle or position, try to only bend the middle section of the feeder.

II. Equipment Preparation

1) Flight Controller: This tutorial is applicable to any of the following flight controllers: SpeedyBee F405 WING APP / SpeedyBee F405 WING MINI / CoreWing F405 WING V2.
2) Peripheral: Siyi HM30

III. Specific Operations

Important

The following tutorial uses the SpeedyBee F405 WING MINI as an example

1) Connect the SBUS port of the HM30 air end to the SBUS input pins of the flight controller board.
2) Connect the UART serial port of the HM30 air end to serial port 4 of the flight controller board.

Important

Note: Generally, only connect TX, RX, and GND, not 5V. The TX and RX of the serial port need to be cross-connected.

Connection Diagram:

Precautions

1. Before use, be sure to check the supply voltage of both the ground end and air end.
2. When ending use, power off the air end first, then power off the ground end.
3. Before setting parameters on the ground end, be sure to power off the engines and motors to prevent accidents.
4. Before use, be sure to pre-set the loss of control protection function on the ground end or in the ground control station software.
5. Before use, power on the ground end first and keep the throttle at the lowest position, then supply power to the air end.
6. During installation, avoid installing the air end too close to the GPS module to prevent interference. It is recommended to maintain a distance of more than 20cm between the air end and the GPS module.

Important

For more information, please refer to the HM30 Full HD Digital Video Transmitter User Manual: https://www.siyi.biz/siyi_file/HM30/HM30%20v1.3.pdf