Measuring_distance

The ultrasonic sensors measure distance by using ultrasonic waves. The sensor head emits an ultrasonic wave and receives the wave reflected from the target. Ultrasonic sensors measuring the time between the emission and reception. The distance can be calculated with the formula L = ½ * t * C (t=time, C=sonic speed). And, to calculate velocity use the formula V = 331.4+0.606T+0.0124H (T=temperature, H= humidity). The humidity and temperature DHT11 sensor is a composite sensor that contains a calibrated digital signal output of temperature and humidity. DHT11sensor is able to measure temperature 0 to 50 Celsius and relative humidity levels of 20 to 80%. In this exercise, the color of the led will change and the buzzer will sound if it is within a certain distance. And, the temperature, humidity, and distance from the object will display on lcd(16x2).