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Mounting the Controller Box

The OnSpeed controller needs a secure mounting location in your aircraft. The box contains sensitive pressure sensors and an IMU, so mounting quality directly affects measurement accuracy.

Location Requirements

Choose a location that provides:

  • Rigid mounting — the IMU measures accelerations. Any vibration or flex in the mount introduces noise. Mount to structure, not fabric or thin sheet metal.
  • Access to pneumatic lines — the controller connects to your pitot, AOA, and static systems. Shorter lines mean faster response.
  • Access to USB port — for firmware updates and serial console debugging.
  • Reasonable temperature — avoid mounting near the engine, exhaust, or heating ducts. The electronics are rated for typical cockpit/cabin temperatures.
  • Wire routing — power, audio, EFIS serial, and flap sensor wires all need to reach the controller.

Common Locations

  • Behind the instrument panel — convenient for wire routing, but can be hard to access
  • Under the seat — easy access, but longer pneumatic and audio runs
  • In a side console — good balance of access and routing distance
  • On the baggage shelf — easy access, but may need longer lines

Physical Mounting

Secure the enclosure using screws, nutplates, or Dual Lock (3M) depending on your aircraft's structure. The enclosure has mounting holes/tabs for this purpose.

Use Dual Lock or rigid fasteners — not regular Velcro

The controller contains an IMU that measures accelerations. Regular hook-and-loop (Velcro) does not hold the box rigid enough and introduces vibration noise that degrades sensor accuracy. Use 3M Dual Lock, the extreme-strength interlocking fastener, or mechanical fasteners (screws/nutplates). Do not hang the controller by its wires or tubing.

Orientation Configuration

The controller can be mounted in any orientation — upright, inverted, on its side, etc. The firmware compensates for mounting orientation using two configuration settings:

  • PORTS_ORIENTATION — Which direction do the pressure ports face? (FORWARD, AFT, LEFT, RIGHT)
  • BOX_TOP_ORIENTATION — Which direction does the top of the box point? (UP, DOWN, LEFT, RIGHT)

These must be set correctly during First-Time Setup. If they're wrong, pitch and roll readings will be incorrect, and your AOA tones won't work.

How to Determine Orientation

  1. Mount the box in its final position
  2. Stand behind the aircraft looking forward
  3. Note which direction the pressure port fittings face — that's your PORTS_ORIENTATION
  4. Note which direction the top of the PCB/enclosure faces — that's your BOX_TOP_ORIENTATION

Verifying Orientation

After configuration, use the SENSORS console command or the web interface sensor page to verify:

  • With the aircraft level on the ground, you should see approximately 1G on the Z-axis (vertical)
  • Pitch should read near 0° (or your aircraft's typical ground attitude)
  • Roll should read near 0°

If the readings are wrong, your orientation settings need adjustment. See Troubleshooting.