sensors...need some help

[JGS93GT]

for my senior design we are basically making a garage door opener, but its for a huge hydraulic door and we are using a PIC to control it and I need to get some sensors for it.
The door is huge that when it swings open it can flip trucks that are parked up against the door and can push away snow up to 3 feet in front of the door.

What would you guys recommend to use for being able to detect if something is in front of the door??? The proximity sensors may not work because we can't have a ton of them on the front of the door. To close it I was thinking of a standard laser/photo beam that goes across so if it is broke when closing the door will stop(its on alot of residential doors today)

Any help would be greatly appreciated!!!

Thanks

 

[kinjalgp]

Yes you are right, you can put a Laser Beam Interrupt detector circuit in front of your door at a particular distance so if any object is within that limit, the door won't open.

 

[JGS93GT]

hey, thanks for replying.......I'm pretty aware of a sensor for the closing part of the door, but what comes to mind when opening the door???
Maybe a vibration sensor???

My problem is getting a sensor to place on the door so that when it opens and hits something, it will stop.

Any suggestions would be great!!
thanks

 

[Sebi]

Most of moving doors have for security a rubber-tube with differential pressure sensor. The tube is fully closed, but contains a small hole for tempereature balancing.If something suddenly pressed the rubber, the pressure increased inside and the pressure sensor can stopped the door.

 

[kinjalgp]

Sebi has a good idea. It can be practically put to work!