ValleyBall

ValleyBall was an idea made by my older cousin because his daughter plays volleyball. I was tasked to see if I could make a proof of concept for the product. Only knowing so little about engineering at the time and only ever tinkering with Arduino’s up until this point, I set out to see if it was already made online.

The objective of this project was to help my niece keep count of how many times she bounces the ball off of the wall during her ‘setter’ drills. I had to take into consideration multiple variables like point(s) of contact, minimum force required, maximum force required, packaging the electronics into the build, what electronics to use, etc. Obviously there’s a lot of thought that goes into making/building anything, so threw all those worries to the side and started programming a simple hardware button.

Multiple Contact Point Issue

The original sensor I made was essentially a button made out of 3 inch cardboard squares with aluminum on one side of each one, and every time they touched it would complete the circuit, adding "1" to the counter.

This is when I ran into my first issue, "multiple contact points". Every time I would touch the aluminum pieces together the counter rapidly count anywhere from 1-10. After a good 30 minutes of figuring out it was a hardware issue, I quickly took to amazon to look for buttons. Fortunately for me, I'm into keyboards and thought of using the spare keyboard switches I had as buttons! (Actually worked out after I figured out how to wire them in parallel)

Asynchronous Issue

I definitely got some gray hairs from this, because the issue now is that I had multiple keyboard switches acting as buttons to keep count of the ball pressing against the plate. Now every time EACH button was pressed it would be counted at the same time. For example, if the ball only bounced off of the target plate once and the plate pressed down on all 5 swtiches, the count would be 5 instead of 1.

Thank the heavens for having friends because my Google searches and forum diving were not helping. My friend Denielle told me what the issue could be and turned out the key word "asynchronous" was all that I was missing. I learned that all my code was lacking was a debounce delay. Debouncing makes sure that only a single signal is accounted for, for a single opening/closing of a circuit.

After a decent amount of testing, I was able to close in on an optimal debounce delay of 50 milli-seconds. This was enough time for the ball to press one to all of the switches, bounce away, and for the switches to bounce back before they were pressed another time.

Conclusion

Unfortunately, by the time I finished making a prototype out of cardboard, hot glued PCBs, and keyboard switches. My cousin had lost interest in the project. Seeing how my motivation was based on how interested he was, I decided to drop the project.

Hopefully one day I can come back to this, because I felt as if this was my first real taste of engineering, and this is where my curiosity started to take root.