Week two consisted of brainstorming different ways a ball could be sensed on a line. The biggest restriction I have for the sensors I use is that they must be thin. This is for the safety of the players.

My original thought for sensing force is force sensitive resistors. The flat FSRs available are generally cheap and accurate. But, they come in many different shapes and sizes. Below are the ones I considered. 

 

The main issue with the force sensors is the amount I would need to use for a whole volleyball court with no dead zones. With the amount I would need to cover the court also comes with an issue of the amount of inputs this would create for the system. This week Professor Buma and I decided to limit the prototype to a 6 foot line instead of a 30 foot end line as I previously wanted at the end of spring term. This decision was made mostly because of cost as well as the amount of time I have for this project!

Another option considered is the capacitive tactile sensors. There are some on the market but most are elevated off of a surface, therefore I could not consider them. But, they are easy to make! 

Basically it is two metal sheets with a dielectric layer in between. This idea was set aside due to accuracy issues and the fact that the signal takes a while to read without certain electronics. This site was very useful in making this decision:

http://www.pressureprofile.com/blog/2014/7/31/three-disadvantages-of-capacitive-tactile-sensors