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    RunCam WiFiLink over USB

    On 4G the RunCam WiFiLink v1 is your drone's camera, not its radio. With the USB firmware it plugs into the companion computer by one USB cable and shows up there as a network adapter, so the Ethernet lead and the USB-LAN adapter come off the airframe.

    Before

    RunCam WiFiLinkEthernetUSB-LAN adapterCompanion4G

    After

    RunCam WiFiLinkUSBCompanion4G
    Status: Beta. Our own SSC338Q drones stream over a USB link like this, but nobody has rewired a WiFiLink v1 yet. Write to us before you open yours and we will do the first one with you.

    Why the Wi-Fi board comes off

    The WiFiLink is two boards stacked: the camera board with the SigmaStar SSC338Q chip, and the Wi-Fi board with its RTL8812EU radio. The SSC338Q has one USB port, and on the WiFiLink it runs to the Wi-Fi board. On 4G the radio has nothing to do, so that board comes off and the USB lines go to the companion instead. The firmware then turns the port around: the camera stops being a USB host for the radio and becomes a USB device for the companion.

    What you need

    • A RunCam WiFiLink v1 (SSC338Q, IMX415), reachable over its Ethernet lead for the flash
    • A companion computer running Aircast, from What You Need
    • A USB cable to cut, with the plug that fits the companion
    • A soldering iron

    Set it up

    1

    Flash the USB firmware

    Do this first, while the camera still answers on Ethernet at 192.168.1.10. Download the firmware, an OpenIPC build for the SSC338Q with the USB network adapter turned on:

    openipc.ssc338q-nor-lite.tgz

    Copy it to the camera and install it. The password is 12345 unless you changed it. The -n flag clears the old FPV settings, and the camera reboots when it is done:

    scp -O openipc.ssc338q-nor-lite.tgz root@192.168.1.10:/tmp/
ssh root@192.168.1.10 sysupgrade -z -n --archive=/tmp/openipc.ssc338q-nor-lite.tgz

    Once it is back, check that the USB device side is there:

    ssh root@192.168.1.10 ls /sys/class/udc

    Success: it prints one controller name. Nothing printed means the old firmware is still on the camera.

    2

    Take the Wi-Fi board off and wire USB to the companion

    Before you separate the boards, see which one the 9-30 V power lead lands on: the camera board has to keep its power. The connector between the boards carries the camera's USB lines. We have not mapped its pins on a WiFiLink yet, so send us photos of both sides of the camera board and we will mark D+, D- and GND with you. Those three wires go to the cut USB cable.

    3

    Add the camera in Aircast

    Plug the cable into the companion and power the drone. The companion gets a new network port, usb0. In the app the drone serves, open Settings → Device → Cameras, open I know my camera's address and paste:

    rtsp://192.168.7.1:554/stream0

    For the port pick usb0, and under Port address & transport set This device's IP on the camera subnet to 192.168.7.2/24. Then press Set up & verify.

    Success: the camera's preview on the Cameras page shows the WiFiLink's picture.

    Stream settings for cellular are on OpenIPC over USB. A companion that does not run Aircast, like the first-generation Radxa Zero, sees the same RNDIS adapter: give usb0 the address 192.168.7.2/24 and pull the stream from that URL.

    Flash your card in about 5 minutes

    The Aircast Flasher downloads the image, sets Wi-Fi and hostname, and verifies the card.

    Download the Flasher