counters

[shadrackthox]

i want to count the number of persons entering/leaving a room and display the output on a 2x16 lcd display....i.e when one enters the room the counter is incremented and the opposite is true,..any help?

 

[donkey]

there are device that do this already. they work of 2 infared beams positioned accross the door about 30cm apart. if you walk one way they send a signel to count up, if you walk the other they send a signal to count down. they have some mis fires but generally work well. will try to see if I can find one for you