sergo101 / stm32f103_max21105_ms5611_vario

Basic altimeter/variometer that fuses accelerometer and barometric sensor data to minimize response lag.

STM32F103 altimeter/variometer with LCD display

Features

Basic altimeter/variometer that fuses accelerometer and barometric sensor data to minimize response lag.

Hardware

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.

Software development environment

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.

Issues

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.