The DS18B20 digital thermometer provides 9-bit to 12-bit Celsius temperature measurements and has an alarm function with non-volatile user-programmable upper and lower trigger points.
DHT11 digital temperature and humidity sensor is a composite Sensor contains a calibrated digital signal output of the temperature and humidity. Today in this tutorial we will be using DHT11 sensor with STM32.
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.
LM35 is an integrated-circuit temperature device with an output voltage linearly proportional to the centigrade temperature. As LM35 is not calibrated in Kelvin, user does not require to subtract large constant voltage from the output to obtain convenient centigrade scaling.