Software
For the software, I aim for the most robust, low-noise evaluation of the sensor data possible. At its core is a Kalman filter that fuses all 10 sensor data streams and calculates a precise vario tone. Added to that is an efficient interrupt-controlled sampling routine and a modular code structure so that future extensions such as GPS logging, FLARM or a display remain easy to integrate.
For simple configuration, all settings can be made using the LiftAir app.
- Firmware updates
- Adjust tone profile
- Change Bluetooth protocol
- Calibration
- and much more.
Hardware
At the core of the hardware are a highly precise barometric pressure sensor, accelerometer, tilt sensor and magnetic sensor. A low-power microcontroller handles the sensor fusion calculations. In addition, there is a Bluetooth module, GPS receiver, solar and a battery for long runtime. The speaker is a piezo buzzer, small, compact and loud. Intuitive control with just one button.
If the battery should still run out, it can be fully charged via USB-C in just 30 minutes.
Housing
The enclosure is incredibly important for good sound. To keep costs low and remain as flexible as possible, I decided to manufacture the enclosures with a 3D printer. ASA-CF should withstand all outdoor conditions.
Later, I would like to switch to injection molding or even milled from ALU.
