IR Blinders?
 

I've just started putting together the IR sensor assembly for my teams robot and I have no idea how much of a blinder system I will need. Unfortuntly my team does not have two 7.2v batteries yet so that has made it a little hard to test the sensor assembly. Also, I was planning on using only two IR sensors, one for the left side, one for the right side of the robot. All the IR systems I've heard of so far use 4 IR receivers. What is the reason for this?

Re: IR Blinders?
 

Many of your questions have been answered by Kevin Watson at http://kevin.org/frc/
In particular check out his FAQ.

You can run everything from a single EDU controller to test with code posted here http://www.chiefdelphi.com/forums/showthread.php?t=24200

You need blinders tightly sealed against light from any direction but the front and one side using Kevin's method. The IR sensor sees equally well in all directions, including directly behind it. A bald sensor will only tell you there ia a beacon in the room somewhere.

The trouble with using a single IR sensor is that it's either on the beacon or not on the beacon. You'd have to put it in a gun barrel. When you lose the beacon you don't know which direction (left or right) to search for it in.
You might be able to implement a constantly scanning search where you keep a servo in constant motion back-and-forth, i.e., "not seeing" the beacon to "seeing" the beacon, to "not seeing", then back again. The servo position value or range of values at each hit of "seeing" could be integrated to provide a useable bearing.

The way Kevin's method works is two IR sensors are setup side-by-side on a servo and the servo is moved to search for the beacon's direction. The IR sensors are arranged so that one sees only to the front and left side, while it's companion sees only to the front and the right side.
When the beacon is to the left only the left sensor sees it and the tracker tells the servo to swivel left until both sensors can see the beacon. Whereupon, both sensors are pointed directly at the beacon and you know what direction it is.

You could also use only one double IR sensor assembly to give you a reliable bearing (direction), but not a triangulated distance to the beacon.
Or vice-versa there is a way to use a single assembly to triangulate a distance, but not to provide a reliable bearing (or not fast at any rate).

Re: IR Blinders?
 

The other thing you must watch out for in your "gun barrel" blinders is to make sure they are in no way reflective. IR, being light, loves to bounce. Use a dull surface to cover your sensors.

Sparks