Distance measurement using InfraRed sensor with ADC0804 & 8051 microcontroller (AT89C51)

Infrared sensors find numerous applications in electronic systems. Commonly used as obstacle detector, their output is used in digital form (high & low logic) by employing a comparator. This topic explains a way to use the sensor’s output in its original analog form. Thus, along with detecting an obstacle, its exact distance can also be obtained. This is achieved by processing the output of IR sensor through an ADC0804 (analog to digital converter). The ADC is calibrated to get almost accurate distance measurement.

The measured distance is also displayed on an LCD screen. The ADC0804 and LCD are interfaced with 8051 microcontroller (AT89C51) to perform these operations. The major drawback of IR based sensors is their capability of detecting short distances.



This project mainly consists of three units: a sensor unit, an ADC component and the LCD module.
The IR receiver detects the IR radiations transmitted by an IR LED. The output voltage level of this IR sensor depends upon the intensity of IR rays received by the receiver. The intensity, in turn, depends on the distance between the sensor module and the obstacle. When the distance between IR pair and obstacle is lesser, more IR radiations fall on the receiver, and vice versa. The receiver along with a resistor forms a voltage divider whose output is supplied as the input for ADC0804.


To download the code for this project click on below button

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