How to's

Setting up the OSD

1. configure general OSD and telemetry parameters in wifibroadcast-1.txt (both on TX and RX)

• Set OSD=Y in wifibroadcast-1.txt (already enabled by default)

• Set the Pi's serial port baudrate to the same baudrate as the serial telemetry data stream coming from the flight control. E.g. OSD_BAUDRATE=57600 if your flightcontrol sends it's telemetry data using 57600 baud.

• For the onboard Pi serial port leave default OSD_SERIALPORT=/dev/serial0, if using an external USB2Serial adapter, set OSD_SERIALPORT=/dev/ttyUSB0

• If you want to connect your flight control to the TX Pi, leave TELEMETRY_INPUT=tx, if you have some other means of transmitting the telemetry to the ground (e.g. an LRS with telemetry downlink) choose TELEMETRY_INPUT=rx to receive the telemetry stream on the ground Pi serial port.

• In case you want to use the OSD included in the Android FP_VR app, also choose the appropriate UDP port to which the telemetry stream will be forwarded by setting e.g. OSD_UDP_PORT=5002 (See in the FPV_VR settings which port is the right one for your telemetry protocol).

2. Configure telemetry protocol and OSD options in osdconfig.txt (only on the RX)

• Remove the "//" characters in front of the #OSD_RSSI and #OSD_RSSI_DETAILED options to enable an RSSI and packets display for the OSD data in the upper right side of the screen. This way, you can see easily check if data is being received. E.g.: #define OSD_RSSI and #define OSD_RSSI_DETAILED

• Choose the telemetry protocol used, Frsky is default, other options supported are Mavlink, Lightweight telemetry (LTM), NMEA GPS. E.g.: #define FRSKY

• Choose graphical OSD options you would like to have enabled in osdconfig.txt. Should be self-explanatory.

• Chose an appropriate update interval for the OSD. 50ms = 20 updates per seconds should be okay for most, if you don't use the artificial horizon or other features that require a high update rate to be smooth, you can increase it. If you feel the OSD is not smooth enough, try decreasing it. Do not go below 20ms. E.g. #define UPDATE_INTERVAL 30

Generally, try to configure your flight control so that it does not send out unnecessary large amounts of data to keep the packet rate as low as possible.

Depending on the amount of data your flight control sends, you may want to increase OSD_BLOCKLENGTH=64 to something larger like 256 to reduce the amount of telemetry packets. Compare the amount of packets of the video stream (on the upper left side) to the amount of packets of the telemetry stream (upper right) to get an idea. The number of OSD packets should not be more than 10% of the number of video packets.

3. Wiring

• Connect the serial port TX pin of your flight control to the serial port RX pin on the Raspberry. WARNING: The Pi uses 3.3V logic level on the serial ports, make sure your flight control also uses 3.3V. 5V might destroy the Pi serial port! (See https://pinout.xyz/ for pinout)

• Power the system up, you should see the received packets counter for telemetry data in the upper right corner increasing. If it stays at zero, there is no telemetry being transmitted/received, re-check wiring, baudrate and flight control settings in that case.

Using configuration profiles

To quickly change settings on the field, eight different configuration profiles selectable via GPIO pins are supported. This way, DIP switches, 3-way switches or jumpers can be used to change configuration, similar to analog gear.

3 GPIO pins give 8 possible combinations, from wifibroadcast-1.txt to wifibroadcast-8.txt. Just copy over the existing configfile with a new number and make desired changes (e.g. frequency, or camera settings) there. If you want to have a means to know which profile is selected on the TX, you can use the raspivid annotation parameters under EXTRAPARAMS to let raspivid insert the profile number or whatever text you would like into the video stream. On the RX there is currently no display which profile has been loaded.

The GPIO pins are being checked during boot-up, to select a different configuration, simply change the DIP-switch (and power-off and on again if the system was already running during the DIP switch change).

Wiring:

GPIO7 | GPIO24 | GPIO23 | wifibroadcast-#.txt
0 0 0 1
0 0 1 2
0 1 0 3
0 1 1 4
1 0 0 5
1 0 1 6
1 1 0 7
1 1 1 8
. 0 = GPIO pin left open
1 = GPIO pin connected to GND