Basic altimeter/variometer that fuses accelerometer and barometric sensor data to minimize response lag.
1.STM32F103C8T6 microcontroller 2.MAX21105 accelerometer+gyroscope 3.MS5611 barometric pressure sensor 4.Salvaged 80x48 lcd front display from old motorola clamshell phone
I am using a homebrew imu breakout board with MAX21105+MS5611+HMC5883L. The magnetometer is not required for the vario functionality. Using it gives you absolute yaw (compass heading) information.
I salvaged a tiny 80x48 pixel LCD display from an old Motorola clamshell phone and used this for altitude/climbrate display. It has an I2C interface.
I used separate breakout boards for the micro-controller and the sensors that I'd designed earlier. So there is no PCB layout for the unified schematic. The battery is a salvaged 3.7V 500mAH lipoly battery. Also added a USB to lipoly charger board.
Ubuntu 18.04LTS, gcc-arm toolchain, openocd, stlink v2 clone for flashing. STM32CubeMx for generating the low level hardware driver files and headers, and startup code.
1.OpenOCD does not sync with this particular micro-controller unless the reset button is pushed. No such issue with GD32F103RCT6 (which is a cheap clone of the STM32F103RCT6). Go figure. 2.Uart serial printf with floats does not work.