Developer juricabi has built StickTime Pi, an open-source project that turns a Raspberry Pi 4 into a "virtual quad". The Pi runs the StickTime FPV simulator and pushes the picture through a 5.8 GHz video transmitter (VTX) wired to its AV jack, so the game shows up in the same analog goggles you use for real flights. You fly it with your own radio over the ExpressLRS/Crossfire WiFi joystick, with no PC and no cable to the radio, at 60 fps and about 25 ms from stick to VTX.
How the picture gets into your goggles
The trick is the Pi 4's 3.5 mm TRRS jack, whose sleeve carries composite video. Wire it to the VTX's video pad (the audio pad can take the game sound too), share a ground, and the Pi becomes a flying camera as far as your goggles are concerned. Composite runs in NTSC or PAL as progressive 240p/288p by default, rendered at twice the lines and scaled down so thin lines and text stay sharp. HDMI works too, for HDMI goggles or any screen.
Native code, no desktop
The simulator itself runs unchanged. StickTime was originally written as an EdgeTX Lua tool that runs on the radio, so StickTime Pi is a native C host that implements the EdgeTX Lua API with Lua 5.3. It draws into RGB565 buffers and shows them with DRM/KMS page flips, with no X, Wayland or browser in the way, and reads the sticks just before each frame. The whole thing is one static aarch64 binary, so an update is a single file.
A neat extra: one wire from GPIO4 through a 1 kΩ resistor to the VTX's SmartAudio or Tramp pad lets the Pi set band, channel, power and pit mode, just like a flight controller. It works out which protocol the VTX uses by itself. The maker warns the Pi's pins are 3.3 V only, so measure the pad first.
Try it
A flashable SD image, a web page at sticktime.local for WiFi, stick mapping, video and VTX settings, and a 3D-printed case for the Pi, VTX and a 40 mm fan are all on GitHub under GPL-2.0. A Pi 3 also works at about half the CPU speed. One safety note from the maker: your radio keeps transmitting while you fly the sim, so take the props off your real quad or unplug its battery.
Image credit: juricabi, from the StickTime Pi GitHub repository, cropped and resized.
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