Main Features

• Centralize configuration file in fat32 partition. Use a single configuration file to configure almost everything you need. The configuration file path is /config/gs.conf and linked to /etc/gs.conf. The partition mount to /config is fat32 format, configuration file can be accessed and edited directly on Windows PC. See configuration part for detial.
• Default wfb key file in fat32 partition. /config/gs.key and linked to /etc/gs.key.
• Button support. There are 8 buttons in plan, they are up, down, left, right, middle and quick 1, 2, 3 buttons.
• Keyboard support. Map keyboard key UP, DOWN, LEFT, RIGHT, 1, 2, 3 to button up, down, left, right, quick 1, 2, 3.
• LED support. Currently support video record LED (Red) and power LED (Green). The green and red LED turn on after the SBC is powered on. Red LED turn off after the system is startup completed. The red LED will blink when video record is turn on. The green LED will blink when OTG mode is switched to device.
• Multiple types of network support. Support WiFi, Ethernet and USB Net, See Network Configuration for details.
• Optional video player. Support pixelpilot, fpvue, gstreamer as Video player. Gstreamer not support OSD.
• Multiple USB OTG gadget functions. Support adbd and CDC NCM, CDC ACM and MASS supported in plan. Use a data cable to connect the computer and the SBC OTG port, adb device and an additional NCM network card will appear on the computer. NCM can auto get ip address with DHCP.
• Temperature monitoring and active cooling. Support monitoring RK3566 and RTL8812EU temperature and automatically adjust PWM fan speed according to temperature.
• Multiple WiFi card drivers. Currently supports RTL8812AU, RTL8812EU, RTL8812BU, RTL8812CU, RTL8814AU, RTL8731BU.
• USB WiFi card hot plug. Support multiple USB WiFi cards with Hotplugging.
• Three wifibroadcast working modes. standalone mode is the native mode with the best compatibility, but hot-plugging USB WiFi card will briefly interrupted the stream. aggregator mode will run wfb_rx aggregator on boot, and run wfb_rx forwarder for each USB WiFi card, hot-plugging USB WiFi card will not interrupt the stram and can receive streams from other external devices through the network like an openwrt router, but may add a little delay (<1ms?). cluster mode.
• Share config and videos with smb. Anonymous access with root permissions is enabled by default, which allows you to easily modify configurations, obtain and delete record files. Enter \192.168.x.x (SBC IP address) in the Windows Explorer address bar to access.
• Auto extend root partition and rootfs. The root partition and rootfs will automatically expand to the size specified in gs.conf->rootfs_reserved_space on initial startup.
• exfat partition for video recordings. Automatically create an exfat partition using all remaining space during initial startup. The partition will be mounted to /home/radxa/Videos for storing video recordings, can get the record files through smb or insert the TF card into the computer.
• Sequentially increasing video file names. SBC has incorrect time without Internet, The gstreamer record video files name sequentially starting from 1000.mkv, Finally video files will be like this: 1000.mkv, 1001.mkv, etc. PixelPilot record file name use template since this commit, Finally video files will be like record_%Y-%m-%d_%H-%M-%S.mp4.
• send stream over USB tethering and Ethernet. Video and telemetry stream can send to other device over USB tethering or Ethernet, witch can be played with Android QGroundControl,PixelPilot etc. Notice: share stream using multicast by default, not working with windows QGroundControl.
• Forward SBC port to IPC over wfb tun. Forward SBC port 2222/8080 to IPC port 22/80 over wfb tun.
• WFB channel scan.
• Version in /etc/gs-release.
• Auto build with github action.

Configuration [ gs.conf for details ]

1. Button Configuration

There are some built-in functions that can bind to button behaviors.

• Buttons
  • Q1, Q2, Q3, CU, CD, CL, CR. (PIN configured in the GPIO section.)
• Button behaviors
  • single press
  • long press (Pressing for more than 2 seconds)
• Button functions
  • change_wifi_mode: change wifi mode between station and hotspot.(Radxa zero 3W)
  • change_otg_mode: change usb otg port between host and device.
  • scan_wfb_channel: search wifi channel used by drone.
  • toggle_record: start or stop record.
  • cleanup_record_files: cleanup record files in order of file names until remaining space(MB) of record partition is large than rec_dir_freespace_min settings.
    CAUTION: Second long press in 60 seconds after first long press will delete all record files.
  • apply_conf: check and apply configuration in gs.conf.
  • shutdown_gs: shutdown ground station.
  • reboot_gs: reboot ground station.
• Default button behavior function
  • Q1
    • single press: toggle_record
    • long press: cleanup_record_files
    • second long press: delete all record files(second long press in 60 seconds after first long press).
  • Q2
    • single press: scan_wfb_channel
    • long press: change_otg_mode
  • Q3
    • single press: null
    • long press: change_wifi_mode
  • KEY_Q
    • single press: null
    • long press: Stop monitoring and use the keyboard as normal. Reseat the keyboard to using as buttons.
  • KEY_S
    • single press: null
    • long press: shutdown_gs
  • KEY_R
    • single press: null
    • long press: reboot_gs

2. GPIO Configuration

Default buttons and LEDs PIN number.

• Quick button PIN
  • BTN_Q1_PIN='32'
  • BTN_Q2_PIN='38'
  • BTN_Q3_PIN='40'
• Custom button PIN
  • BTN_CU_PIN='18'
  • BTN_CD_PIN='16'
  • BTN_CL_PIN='13'
  • BTN_CR_PIN='11'
• LED PIN
  • RED_LED_PIN='22'
  • GREEN_LED_PIN='15'
  • BLUE_LED_PIN='12'

3. Network Configuration

• WiFi: wlan0
  • station mode: Default connect to an open WiFi named OpenIPC if not configured.
  • hotspot mode: Default SSID is SBC-GS with password 12345678, IP is 192.168.4.1/24
• Bridge: br0 Default DHCP client with static IP 192.168.1.20/24, 10.0.36.254/24
• Ethernet: eth0 Default slave of br0.
• USB tethering: usb0 Default slave of br0.
• USB gadget ncm: radxa0 Default DHCP server with static IP 192.168.2.20/24

4. Video Configuration

• video_on_boot: used to control showing video or terminal console after startup. Default is yes. Set it to no will boot into the terminal and only recommended for development and debugging.
• osd_config_file: pixelpilot's osd config file. Default is /config/pixelpilot_osd.json. Use /config/pixelpilot_osd_simple.json for less osd elements when using msposd.
• screen_mode: used to set the screen resolution and refresh rate. e.g. 1920x1080@60. Default is blank and will auto detect by pixelpilot or SBC. Recommended set it manually only when preferred screen mode is not the best.
• CAUTION: Resolution is limited to 1920x1080 by radxa, can changed by setting max_resolution_4k to yes in System Configuration section.

5. Record Configuration

• REC_Dir: the record storage location. Default is /home/radxa/Videos.
• rec_dir_freespace_min: the minimum remaining space before recording. When press the record button, if remaining space is lower than this value, it will prompt that there is insufficient space and the recording will not start. Default is 1000MB.
• REC_FPS: Record video fps and must same video fps set on drone. Default is 60.
• CAUTION: OSD will not be recorded.

6. Wifibroadcast Configuration

7. System Configuration

Recommended GPIO Functions

Purpose#1	Recommended Function#1	Pin#1	Pin#2	Recommended Function#2	Purpose#2
+3.3V	+3.3V	1	2	+5.0V	+5.0V
telemetry	UART3_RX_M0	3	4	+5.0V	+5.0V
telemetry	UART3_TX_M0	5	6	GND	GND
PWM_FAN	PWM14_M0	7	8	UART2_TX_M0	DEBUG
GND	GND	9	10	UART2_RX_M0	DEBUG
BTN_R	GPIO3_A1	11	12	GPIO3_A3	BTN_L
BTN_U	GPIO3_A2	13	14	GND	GND
BTN_D	GPIO3_B0	15	16	PWM8_M0 / UART4_RX_M1	AAT_SERVO
+3.3V	+3.3V	17	18	PWM9_M0 / UART4_TX_M1	AAT_SERVO
SPI_SCREEN	SPI3_MOSI_M1 / PWM15_IR_M1	19	20	GND	GND
SPI_SCREEN	SPI3_MISO_M1 / UART9_TX_M1	21	22	GPIO3_C1	SPI_SCREEN
SPI_SCREEN	SPI3_CLK_M1 / PWM14_M1	23	24	SPI3_CS0_M1 / UART9_RX_M1	SPI_SCREEN
GND	GND	25	26	NC	NC
COMPASS / USB D+	I2C4_SDA_M0 / USB D+	27	28	I2C4_SCL_M0 / USB D-	COMPASS / USB D-
SPI_SCREEN	GPIO3_B3	29	30	GND	GND
BTN_Q1	GPIO3_B4	31	32	UART5_TX_M1	GPS
GPS	UART5_RX_M1	33	34	GND	GND
BTN_Q2	GPIO3_A4	35	36	GPIO3_A7	RECORD_RED_LED
BTN_Q3	GPIO1_A4	37	38	GPIO3_A6	PWR_GREEN_LED
GND	GND	39	40	GPIO3_A5	RC_BLUE_LED

8. Cooling Configuration

Files and Services

• build files: script files for build images
• workflows files: Auto build images using github action
• gs files:
  1. Configuration file /config/gs.conf
  2. wfb key file /config/gs.key
  3. script files /home/radxa/gs/[button.sh, channel-scan.sh, fan.sh, gs-init.sh, gs.sh, stream.sh, wfb.sh]
  4. udev rule files /etc/udev/rules.d/[98-gadget.rules, 99-wfb.rules]
• Services:
  1. gs.service
  2. stream.service (temporary unit)
  3. button.service (temporary unit)
  4. fan.service (temporary unit)
  5. unnamed temporary services started for each USB WiFi card in wfb aggregator mode

GS Directory Tree
/
├── boot
│   └── dtbo
│       ├── rk3566-dwc3-otg-role-switch.dtbo
│       └── rk3566-hdmi-max-resolution-4k.dtbo.disabled
├── config
│   ├── custom-sample.conf
│   ├── gs.conf
│   ├── gs.key
│   ├── pixelpilot_osd.json
│   └── pixelpilot_osd_simple.json
├── etc
│   ├── gs.conf -> /config/gs.conf
│   ├── gs.key -> /config/gs.key
│   ├── gs-release
│   ├── iptables
│   │   └── rules.v4
│   ├── network
│   │   └── interfaces.d
│   │       └── radxa0
│   ├── NetworkManager
│   │   ├── conf.d
│   │   │   └── 00-gs-unmanaged.conf
│   │   └── system-connections
│   │       ├── hotspot.nmconnection
│   │       └── wlan0.nmconnection
│   ├── samba
│   │   └── smb.conf
│   ├── systemd
│   │   ├── network
│   │   │   ├── br0.netdev
│   │   │   ├── br0.network
│   │   │   ├── dummy0.netdev
│   │   │   ├── dummy0.network
│   │   │   ├── eth0.network
│   │   │   └── usb0.network
│   │   └── system
│   │       ├── gs-init.service
│   │       ├── gs.service
│   │       └── multi-user.target.wants
│   │           ├── gs-ini.service -> /etc/systemd/system/gs-ini.service
│   │           └── gs.service -> /etc/systemd/system/gs.service
│   └── udev
│       └── rules.d
│           ├── 98-gadget.rules
│           ├── 99-kbd.rules
│           └── 99-wfb.rules
├── gs
│   ├── button-kbd.py
│   ├── button.sh
│   ├── channel-scan.sh
│   ├── fan.sh
│   ├── gs-applyconf.sh
│   ├── gs-init.sh
│   ├── gs.sh
│   ├── rk3566-dwc3-otg-role-switch.dts
│   ├── rk3566-hdmi-max-resolution-4k.dts
│   ├── stream.sh
│   └── wfb.sh
└── Videos

Hardware

Designed for and tested on Radxa Zero 3W/3E only.

• Buttons: All buttons must connect to 3.3V.
• LEDs:
  1. GPIO work in Push-Pull mode. GPIO->Resistor->LED->GND
  2. GPIO work in Open-Drain mode.

  3V3->Resistor--->LED->GND
                │  
               GPIO
  

Troubleshooting

1. Access to SBC console. Default username/password is radxa/radxa and root/root
   • ssh over network with wireless(hotspot/station), ethernet or usb gadget ncm.
   • serial console with usb uart.
   • terminal console with keyboard.
   • adb with usb otg.
2. Check gs service logs
   • systemctl status gs
   • journalctl -u gs

TODO

• Automatically select the video storage location according to the priority of external storage > TF card > emmc
• Adaptive-Link support
• improver support
• Change the built-in LED to a normal GPIO LED
• Screenshots
• Record video playback
• Unify variable names

Known issues