entrance counter (89c51)

I want to make a human counter for exit and entrance for a house using sensors and 89c51 microcontroller, which type of sensors i would use? and i want to operate a bulb using this, the logic is that when nobody is in the house the bulb turns off and when some body enters it turns on..
can somebody help please??
I want a circuit diagram for this.?

If you want a circuit diagram you shold draw one. Draw it on paper and scan it, or download the free tools from expresspcb or linear technology. Make some effort and you'll find a more recpetive audience.

The more you plead, whine, and beg the less sympathy you'll get.

My idea, you should you Range Sensor such as GP2Y0A21YK/ GP2Y0D21YK to detect the object combine with Timer/Count modules in 8051. If output from the sensors is Analog should convert it using ADC. For my work I use ADS7841 and p89v51. It is a long story, please see
https://mcu-programming.blogspot.com/2006/09/adc-interfacing.html

hey, im making an intruder alarm for which i need sensors at door and window so that when they are opened sensor send signal to microcontroller. Which sensor should i use?? can anyone please giv names of commercially available sensors too....

for this perpose u may use pir sensor. which detect any movement.

thanks