Sensors and fusion
- Pressure sensing
- Two independent barometers
- Measured improvement
- 26% cleaner pressure input in a stationary one-minute test
- Motion sensing
- Low-noise 6-axis IMU
- Processing rate
- 100 Hz sensor fusion

A change in pressure reveals movement in the air.
Give your next climb a listen.
Sound preview · Your Duo’s tones are fully customisable.
Clear audio feedback helps you follow the lift and focus on your flight.
A compact variometer.
For a pleasant flying experience.
Fine-tune Duo’s tone curve in the FlySys app, and enjoy your flight.
Explore the FlySys appYour settings stay on Duo. Enjoy standalone audio without keeping your phone connected.
Fly by sound. Standalone climb & sink audio.
Make it yours. Customisable tone curves.
Stay connected. Live flight data on your phone.
Sensor architecture
Duo measures pressure with two independent barometers and combines their averaged signal with low-noise motion data at 100 Hz. Explore the same recorded movement processed by the two barometers, the complete FlySys Duo sensor fusion, and a simulated conventional pressure-only variometer.
This ten-second capture lets you see and hear the difference between the final FlySys Duo signal, its two barometers, and a simulated conventional pressure-only variometer. Every view uses the same recorded movement, making noise and response delay directly comparable.
FlySys Duo combines both barometers and then fuses their pressure signal with IMU data. The classic response remains visible in grey so its additional delay can be compared directly.
Duo Baro 1
+0.40 m/s
Duo Baro 2
-1.62 m/s
Duo combined
-0.61 m/s
IMU-fused
-0.20 m/s
Classic Baro
+2.34 m/s
Classic average
+0.22 m/s
Battery autonomy
Choose where your vario tones play, turn Bluetooth streaming on or off, and adjust the data rate, LED brightness and volume to see how each setup affects estimated flight time. The calculation uses the current 1500 mAh battery.
Choose where tones play
Estimated autonomy
2 days 8 hours
Estimated with a full 1500 mAh battery
Bluetooth live data
Duo operates independently without Bluetooth streaming.
Higher rates update the phone more frequently and reduce autonomy.
20 samples/s
Estimates use measured Duo consumption and approximate sound/LED additions. Actual autonomy varies with flight conditions, temperature, battery age and usable capacity.
Technical specifications