The process is pretty straight forward. We will set the data pin as input and count the number of times it goes high and low in 1 second and that will be the input frequency. I am using NE555 to generate different frequencies and DSO138 to compare the results to.
The ADXL345 is a complete 3-axis acceleration measurement system with a selectable measurement range of ±2 g, ±4 g, ±8 g, or ±16 g. It measures both dynamic acceleration resulting from motion or shock and static acceleration, such as gravity, which allows the device to be used as a tilt sensor. In this tutorial we are going to interface ADXL345 with STM32.
This oled display uses the I2C protocol to communicate to the microcontroller. So here you need only 2 pins i.e. SDA and SCL from the microcontroller and..
inorder to initialise the sensor, we hae to pull the data line LOW for around 500 us (microseconds) and pull it HIGH for around 20-40 us. After this DHT22 will pull the line low for 80us and than high for 80us.