Clap counter using 8051 microcontroller (AT89C51) Summary Description Circuit Diagram Code Components SummaryThis article explains the concept behind interfacing a sound sensor with the 8051 microcontroller (T8!C51"# This pro$ect increases the count by one e%ery time a sound is produced# &t wor's well with the sound of a clap# The number of claps is displayed on an (CD module# The circuit consists of four modules) namely) a sound sensor) an amplifying circuit) a control circuit and a display module# The code for interfacing the sound sensor with the *C+ is written in C language#Description The connections of different modules are shown in the circuit diagram# The data pins of the (CD are connected to port ,-) while the control pins (.S) ./0 1 23" are connected to pins 145 of port ,1of T8!C51) respecti%ely# The microcontroller recei%es sound pulses through the first pin of port ,0# condenser microphone is used to sense the sound produced by the clap# This mic is connected to a two stage transistor amplifier# The mic output is thus amplified to a suitable le%el so that it can be detected at the TT( logic#switching circuit made from a single transistor is also employed after the amplifier# The purpose of this circuit is to con%ert the analog signals into discrete digital signals) which are used as input for the *C+#The output of the amplifier is coupled with a transistor switch# 0hene%er a high %oltage output is recei%ed from the amplifier) it generates a pulse# The transistor switching circuitalso ensures that a high TT( logic is not recei%ed at the microcontroller due to noise signals#The pulse) from the switching circuit) is fed to the microcontroller) which is programmed to detect the pulses# 2%ery time a pulse in detected) the count %alue is increased by one#The output is displayed on a 16x- (CD screen# Thesensiti%ityofthesoundsensorcanbeincreasedbyimpro%ingthecircuit ofthe amplifying unit# n op4amp can be used to increase the sensiti%ity# Circuit DiagramCode// Program to count the number of clap#include#define port P1#define dataport P2//Data Port for LCD#define sec 1sbit rs ! port"#sbit r$ ! port"1#sbit e ! port"2#sbit sensor%input!P"#unsigned char str&'1(!)* *+* *+* *+* *+* *+* *+* *+* *+* *+* *,#-oid dela./unsigned int msec0 // 1ime dela. function)int i+2 #for/i!#i0)str&'i(!/num;103