We, three 10th graders in a German high school, would like to build a goal line technology system as a project with the Arduino, like in football. For it we would like to supervise the goal line with movement sensors (light barriers). If the ball crosses the goal line, a LED should shine and concern a music.
We put the question to ourselves what exact sensor would be relevant for us, because we do not know a lot about sensors yet so properly.
Please, help us, so that we can put into action our project.
Well that was talking about a robot acting as a goal keeper, this is talking about real world sensors.
For it we would like to supervise the goal line with movement sensors (light barriers). If the ball crosses the goal line, a LED should shine and concern a music.
You have to have a system that distinguishes the ball from a player, that is the big problem.
The second big problem is that you have to detect when the ball has completely crossed the line, so any single sensor on the line will not be able to distinguish between the state of the ball being in play and in the goal.
You can consider a sensor in the ball, but the only practical solution is the one currently used concerning video triangulation and motion prediction.
We, three 10th graders in a German high school, would like to build a goal line technology system
Given the events of the world cup back in 2010, I would have thought that Germans would be keen not to have workable goal line technology, or are you thinking about 1966?
Yeah we are still thinking on 1966 but you are right with 2010 too
With our project it plays no role whether to the example the goalkeeper reaches behind the line. That is why we do not need to follow the first problem.
The second problem is more relevant and this question we have already positioned ourselves. We would like to build light barriers behind the goal line, then these should give a signal. Do you have an idea which light barriers we could use for it?
You could put a lidar in the corners of the goal.
The laser would detect a constant pattern of distances, indicating an empty goal.
The pattern is a shifted/ transformed rectangle, but constant up to some noise level.
If the bal is going into the goal the pattern the lidar sees is disrupted.
The new pattern holds information about the size of the object (keeper, player, ball, shoe, bottle ...)
Another idea could be to add reflecting foil a the inside of the poles.
put one laser under a angle so it bounces upwards (angle should be chosen that a ball cannot pass though)
at the top you place a detector that sees the laser light.
if interrupted you have detected something.
As this is an on-off you cannot say if it was the ball or something else.
Spotting the difference between a ball going in and a spinning ball partially crossing a line and bouncing out.
If you put sensors on the post then it only has crossed the line when it blocks the sensor and then no longer blocks it.
The simplest way it to put a laser / detector pair on opposite posts at a spacing of a half ball diameter, but while it is simple it will be difficult to fabricate and align and more importantly keep being aligned.
If the bal is going into the goal the pattern the lidar sees is disrupted.
The new pattern holds information about the size of the object (keeper, player, ball, shoe, bottle ...)
That is one of those theoretical solutions that in the end would probably not work. It is basically an image recognition problem which is bad enough but in the frequency domain which in my opinion would make it a PhD project and one that would probably fail anyway.
