مرکز منطقه ای اطلاع رساني علوم و فناوري

Abstract :

A light sent by the LED reflects back after impact on a target. The radiant power of reflected light is turned into voltage by a photodiode near the LED. The photo detector voltage is inversely proportional to the square of the distance which LED’s light had traveled. In this study, this voltage has been turned into a voltage which is proportional to the distance at the output of the distance meter circuit using the logarithmic and antilogarithmic amplifiers. The circuits which have been designed in this study are analog circuits and these circuits consist of passive elements, transistors, operational amplifiers, 555 timer and a sample and hold integrated circuit. In this study, LED is used in pulsed high current operation to increase LED radiant power and to measure long distance. At the same time, the background noise which is produced by the other light sources in the medium has been reduced by using of the LED in pulsed high current operation mode.