Re: Help needed for circuit design

[snooddle]

Re: Help needed for circuit design

Hi, I'm doing a project on a in/out counter using infra-red detectors used in hospitals.

My project needs to be able to detect anyone going into the room and out of the room and plus/minus from the display accordingly. It mus also be able to differentiate between person, wheelchair and hospital bed. Each entry of wheelchair will be considered as 2 persons and each entry of a hospital bed is considered 3 persons. Anyway to do this kind of circuit?Can anyone pls tell me where to get this kind of circuit design or have any suggestions on how to improve my project? Thx........

Pls help.... thx thx....

 

[aryajur]

Re: Help needed for circuit design

Long time back I made a circuit which could add/subtract the number of people going in/out, in a digital display. But it did not have facilities to detect beds and wheelchairs. To detect a bed, I guess you can add some sensors on the top and bottom of the doorway since a bed will take a longer time to paas and will be wider thus the top to bottom sensors will be interrupted for a long time in a wide range. Wheel chair is tricky. One way to detect it would be to have pressure sensors right at the door frame. Because a person walking would rarely stand at the door frame with both his feet on the pressure sensors, while a wheel chair will always cross that line, and thus go over the sensors and thus be detected. A bed will do this 2 times, so maybe you won't need the top bottom sensors.
So I guess the whole system can be made by using infrared sensors for people and pressure sensors for beds and wheel chairs.

 

[snooddle]

Re: Help needed for circuit design

Yup, your point is noted. but the problem is that the door that we are introducing this system is very wide so we do not know exactly which part of the door that the wheelchair will pass by. so we cannot determine where to place the pressure sensor. and the durability of the pressure sensor is questionable. in addition, we have a tight budget. we need to try to keep the cost to the minimum.
Anyway thx for you help. do you have the diagram of the circuit? is it ok for you to email that to me?
email: luv_xian09@yahoo.com.sg

 

[aryajur]

Re: Help needed for circuit design

Right now I don't have time to draw the circuit, I don't have it drawn already with me at present. The hint is use 2 light beams and determine their order of interruption to determine the direction of movement of a person.
Also if a door is really wide then it will be difficult to ensure people enter in a single file, and if they don't, this type of circuit won't work. If you do ensure single file, I think you have to have a strips of pressure sensors, to cover major length of the bottom of the door frame, each strip length less than the width of the wheelchair wheels.