The Standby Horizon is a gyroscopic attitude indicator. It is also sometimes refered to as the artificial horizon. It is a precision flight instrument that informs the pilot of the aircraft orientation relative to Earth's horizon. It is a standby instrument that is used only in case when the horizon on the Primary Flight Display (PFD) fails. It has a caging knob that can be pulled by the flight crew to reinitialize the gyro, in order to level and center the horizon.
The Standby Horizon has been build as a stand alone application that can run on Microsoft Windows or on Linux (using Mono). It communicates with the A320 Simulator Software core over a LAN network.
By attaching a small screen to a Raspberry Pi and running the Standby Horizon application on it, a compact integrated module can be realized that can be fitted easily into any cockpit.
In the video below you see on the right hand side a remote screen login from a PC into a Raspberry Pi. On the left hand side you see a test application running on PC.
When the Standby Horizon application is launched on the Raspberry Pi using Mono, it automatically discovers the presence of the test application and subscribes to its data stream.