photoresistor + entrance gate(count people)

hi,i would like to have something like a photoresistor (or photo cell) on entrance gates to count those passing through. i have so many gates,how do i connect so many sensors to one computer? can i recieve such signals from rj45(ethernet) ? regards

westfw10 years ago
You get to run a balancing act between the cost of the equipment at each gate, and the cost of running wire to each gate. You can certainly run info over ethernet using some sort of equipment at each ethernet connection point (ie, if you have a PC already there, that could do it based on a simpler HW interface to the actual sensor. Alternately, wireless "sensor networks" like zigbee are aimed at supporting this sort of application. In any case, if you're not buying someone's packaged solution, you'd have to write a substantial amount of software.