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INTRODUCTION
This is a useful circuit for various purposes. In this circuit a counter is activated when a continuously supplied light is been blocked. It uses a counter IC CD 4033.An LDR enhances the counting process.
This circuit an be used for various applications such as to count products going over a belt, and for counting persons passed at a point etc
The project is done as a prototype and its Real one can display a three to ten digit numbers and can count unto thousands.
CIRCUIT EXPLANATION
The circuit is using an op-amp LM 311. The sensor circuit formed using LDR1 activates counter 4033.LDR1 has a resistance of 2.2 kilo-ohms in daylight, which drops below 50 ohms when light beam falls on it. (An LDR of nearly 2cm diameter has been used in this circuit.) Comparator LM311 (IC1) compares the level set at pin 3 (nearly 6V, set using a 47k pot) with the level at pin 2. When light is falling on LDR1, its voltage is above 1V and IC5 has a low output at its pin 1. When no light is falling on LDR1, its voltage drops below 1V and IC1 output at its pin 1 becomes high.
The output from the Op-amp is given as the clock for seven segment counter 4033.The counter count 1 for each high going pulse.The 4033 encodes the count to display number in seven segment display CE c5611
COMPONENT DETAILS
 LM 311
General Description
The LM111, LM211 and LM311 are voltage comparators that have input currents nearly a thousand times lower than devices like the LM106 or LM710. They are also designed to operate over a wider range of supply voltages: from standard ±15V op amp supplies down to the single 5V supply used for IC logic. Their output is compatible with RTL, DTL and TTL as well as MOS circuits. Further, they can drive lamps or relays, switching voltages up to 50V at currents as high as 50 mA.
Both the inputs and the outputs of the LM111, LM211 or the LM311 can be isolated from system ground, and the output can drive loads referred to ground, the positive supply or the negative supply. Offset balancing and strobe capability are provided and outputs can be wire OR’ed. Although slower than the LM106 and LM710 (200 ns response time vs. 40 ns) the devices are also much less prone to spurious oscillations. The LM111 has the same pin configuration as the LM106 and LM710. The LM211 is identical to the LM111, except that its performance is specified over a −25°C to +85°C temperature range instead of −55°C to +125°C. The LM311 has a temperature range of 0°C to +70°C.
Features
 Operates from single 5V supply
 Input current: 150 nA max. over temperature
 Offset current: 20 nA max. over temperature
 Differential input voltage range: ±30V
 Power consumption: 135 mW at ±15V
 IC 4033
CD4033BMS consists of a 5 stage Johnson decade counter and an output decoder which converts the Johnson code to a 7 segment decoded output for driving one stage in a numerical display.
This device is particularly advantageous in display applications where power dissipation low and/or low package count is important.
A high RESET signal clears the decade counter to its zero count. The counter is advanced one count at the positive clock signal transition if the CLOCK INHIBIT signal is low. Counter advancement via the clock line is inhibited when the CLOCK INHIBIT signal is high. The CLOCK INHIBIT signal can be used as a negative-edge clock if the clock line is held high. Antilock gating is provided on the JOHNSON counter, thus assuring proper counting sequence. The CARRY-OUT (Cout) signal completes one cycle every ten CLOCK INPUT cycles and is
used to clock the succeeding decade directly in a multi-decade counting chain. The seven decoded outputs (a, b, c, d, e, f, g) illuminate the proper segments in a seven segment display device used for representing the decimal numbers 0 to 9. The 7 segment outputs go high on selection.