EFIS Integration

Connecting OnSpeed to your EFIS (Electronic Flight Instrument System) significantly improves system performance. The EFIS provides calibrated IAS, OAT, attitude data, and more — data that OnSpeed uses for better AOA computation and density corrections.

Why Connect Your EFIS?

With EFIS	Without EFIS
Calibrated IAS from pitot system	IAS from OnSpeed's own pitot sensor (still works, but less precise)
OAT from EFIS probe	Requires DS18B20 sensor, or no temperature correction
Attitude from EFIS AHRS	Uses OnSpeed's internal IMU only
Altitude from EFIS	Computed from static pressure sensor
Fuel, RPM, MAP data logged	Not available

OnSpeed works without an EFIS — but the calibration and accuracy are better with one.

Supported EFIS Types

EFIS	Protocol	Status
Dynon SkyView / HDX	Text serial (!1 ADAHRS + !3 EMS)	Fully supported — most common
Dynon D10/D100	Text serial	Supported
Garmin G5	Text serial	Supported
Garmin G3X / G3X Touch	Text serial	Supported
MGL iEFIS / Odyssey	Binary (iLink protocol)	Supported
VectorNav VN-300	Binary (127-byte packets)	Supported — research/reference use
No EFIS (Standalone)	—	Works, with limitations

Common Serial Settings

All EFIS types use the same serial settings on the OnSpeed side:

• Baud rate: 115200
• Data bits: 8
• Parity: None
• Stop bits: 1
• Flow control: None

The EFIS must be configured to output serial data at 115200 baud. This is not always the default — check your EFIS manual and the specific integration page.

Wiring

Connect your EFIS serial TX (transmit) output to the OnSpeed RX (receive) input:

• OnSpeed RX pin: GPIO 11 (through ADM3202 RS-232 level shifter on the PCB)
• OnSpeed TX pin: GPIO 46 (not connected — OnSpeed only receives from the EFIS)

TX to RX — not TX to TX

Serial connections are crossed. Connect the EFIS transmit pin to the OnSpeed receive pin. This is the most common wiring mistake.

Configuration

After wiring, set the EFIS type in the OnSpeed web interface:

1. Connect to OnSpeed WiFi (OnSpeed / angleofattack)
2. Navigate to the configuration page
3. Set EFIS Type to match your hardware
4. Save and reboot

EFIS type must match your hardware

Setting the wrong EFIS type means OnSpeed will try to parse serial data in the wrong format. You'll get no EFIS data or — worse — garbled data. Always verify the EFIS type matches what you've wired.

Verifying EFIS Data

After configuration, verify data is flowing:

1. Use the SENSORS console command (via USB serial) — EFIS fields should show non-zero values
2. Check the web interface live view — EFIS IAS, OAT, and attitude should display
3. In the log files, check the efisAge column — this should show small values (< 1000 ms). Large values mean data isn't arriving.