This project is multipurpose and used in many other projects. IC 4033 has been used in this project. With the help of this project you can very easily count and see up to 99 in this FND counter. This project is a novelty in the electronic world. LDR has been used in this project. When light falls on a LDR it changes its internal resistance (more or less) according to amount of light falling it.

TECHNICAL DESCRIPTION AND WORKING
The IC 4033 is decade counter and 7 segment Decoder. Working of this project is very simple. We get triangular pulse from pin no 1 of IC 4033, when light falls on the LDR. The pin no 5 carries output and pin no 15 is the reset pin. One no is increased on output display when positive going pulse is received on pin 1 of IC 4033. on getting second pulse on more no. is added. When 0 to 9 cycle is completed then 1 positive going pulse is received on pin 5. This positive going pulse increases 1 no on ICs tens. Like this it goes up to the no. 99. further increase of positive pulse gibe 00 on the display. If no. of IC 4033 is made 3 in the project, then display of no will be 999. the reset pin if not used in the circuit.

http://ziddudownload/5388059/PCM.doc.html