sensor help?

[karlos]

Hey,

I'm currently doing an ONC engineers course in electrical engineering and I'm looking for some advice about sensors.

For my project I am designing a low budget goal line technology system and part of my product design specification process (I don't have to build the product as part of my course work) requires me to identify three methods in which a goal line system could work, and then select one for my final design.

So, for my first design I'm looking into using RF sensors in the ball.

But for my other two ideas I was wondering if anyone knows of a sensor that reacts to a specific colour, should I set the football as this specific colour. And finally how could I use an IR sensor to work in my system.

A point in the right direction would be greatly appreciated. I am a complete novice when it comes to electronics.

 

[hevans1944]

The cheapest way to sense when a soccer ball crosses the entrance plane of the goal cage would be to photograph the goal in real time with one or more video camera(s) having a sufficiently high frame rate. Then use real-time digital image processing of sequential frames to determine when the ball crosses the goal line. This is not a new idea, but until recently the computing "horsepower" to accomplish goal-detection in real time, rather than post-processing the data, has not been readily available at the consumer level.

If video real-time detection of goals appears attractive to you, read this paper to get started down that road. All you need is some inexpensive video cameras, a modern personal gaming computer, and a little software. Well... a LOT of software, actually, but you did say you didn't need to build it, just describe it.

The problem you are trying to solve is not trivial, even with multiple TV cameras to ensure the goal shot is detected and not obscured by people on the playing field. Other approaches, such as visible or IR "light ladders" criss-crossing the goal line, with spaces between rungs narrow enough to guarantee the beam is interrupted by a passing ball, are not exactly cheap and they can be cumbersome to erect and align. The problems associated with a sensor and/or transducer embedded in the soccer ball are many. The most obvious is how to detect when the sensor actually crosses the goal line. And how do you install the sensor assembly in the soccer ball, and change (or re-charge) its battery without affecting the balance and weight distribution of the ball? How is this approach inexpensive compared to a few video cameras with wi-fi links and a laptop PC?

Perhaps the most practical solution is to station an observer at each goal. If the observer sees a goal occur, they press a wireless key-fob button to signal the event, alert officials on the field, and illuminate a big light and perhaps a horn. Then officials can confirm or deny the opinion of the observer with an instant TV replay, just like we do here in America with our football games. I would bet, given the response time of human reflexes, that the video processing solution will not only give "instant" results but provide :"backup" proof of its decision. You can eventually eliminate the human observers completely. Put that in your pipe and smoke on it FIFA.

 

[davenn]

The most obvious is how to detect when the sensor actually crosses the goal line. And how do you install the sensor assembly in the soccer ball, and change (or re-charge) its battery without affecting the balance and weight distribution of the ball?

Just an RFID tag ... no batteries needed

RFID would be my choice of detection for this sort of application

 

[hevans1944]

Just an RFID tag ... no batteries needed

RFID would be my choice of detection for this sort of application

How do you use an RFID tag to determine that the ball crosses the goal line? Put the interrogating transceiver at the back of the cage? Could work if there were never any false positives. Maybe embed the transceiver antenna in the cage framework? RFID is worth a try.