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Variometer for Paraglider Pilots

Consumer electronics Embedded hardware development Firmware development Sports equipment Wearable

A variometer is a device used by paraglider pilots at competitions. It informs the pilot of the rate of descent or climb. A variometer records data such as speed, altitude, and climb rate, and can send this data over Bluetooth or USB to a smartphone, a tablet, or an e-reader.

Request

One of the leading Swiss companies that produce products for paraglider pilots turned to Integra Sources to enhance their existing variometer.

Solution

We provided PCB design and ported the existing firmware from Arduino to the new hardware. The project is based on STM32F4 microcontroller. It runs on RTOS (Real Time Operating System) and uses the FatFS filesystem module to store data on the SD Card. We enhanced the algorithm for calculating the final results, taking into consideration the new hardware and the device’s physical characteristics.


Scope of work

  • Schematics design
  • PCB design
  • Generation files for the manufacturer
  • Hardware testing
  • Debugging
  • Firmware development

Technologies Used

  • STM32F4 series MCU with Cortex-M4 core was used in this project.
  • FreeRTOS was used for firmware development.
  • The firmware was implemented using C/C++.
  • Eclipse IDE with GCC and OpenOCD was used for firmware implementation.
  • SD-Card was used to store tracking data.
  • EAGLE CAD IDE was used for Schematics and PCB design.
  • For precision positioning, GPS, accelerometer, and gyroscope were used.

Result

The result of our work is a new version of the variometer. A paraglider pilot uses it during flights to ascertain that the correct flight level is being maintained. The variometer indicates the climb/sink rate using beeping tones without any time lag. It has a set of sensors including accelerometer, gyroscope, temperature, GPS, and barometer. It informs the pilot about altitude changes, tracks their position via GPS and stores detailed data about the flight on an SD card.

When the flight is over, a pilot can transfer the data using Bluetooth to their smartphone, tablet, or laptop. They can also analyze these data using special software. The data format we used for saving flight data is compatible with data formats used by software applications.

The variometer has a built-in solar cell but the battery can also be charged over the micro USB cable. It will run for 20 hours with a fully charged battery.

Pilots can also use the variometer as an IGC (International Gliding Commission) logger.

Battery life

20 hours

Average refresh rate

10 Hz

Measurement precision

90%