Introduction

So for third term in Maker Time we had to do a Blue Sky project. If you don’t know what that is then here is a brief description. A Blue Sky project is basically just an inquiry project but our PLP teachers like to call it something different. We had to base our project around solving a problem. My problem was the fact that umpires are never perfect. So I tried to make an Automated Strike Zone to relieve the pressure of calling balls and strikes from the umpire.

This is my post about the problem I wanted to solve and some information about umpire accuracy.

Pitch Form

Before we can start work on our projects we have to write a pitch form to out teachers and hopefully get it approved. I was lucky, my first pitch form got approved.

You can view my full pitch form here.

Research

To get started on my project I did some research about how I could build the strike zone. I pretty quickly decide to use Raspberry Pi and figured that I could use some sort of lights that would detect when the ball when through the right area. My early ideas were to use LEDs, Infra-red or maybe lasers and detect the light using photo cell sensors.

Once the Raspberry Pi arrived I need to start learning how to use it. My Dad and I spent a couple of weekends with him teaching me the basics of Linux, and GPIO programming. We did some sample programs that controlled LEDs so I could learn about how this worked.

This blog post describes this stage in more detail.

Building Prototype

It was finally time to make the first prototype. We cut a square out of a cardboard box and put a white LED on one side, and a photo cell on the other. For the ball I had a small bouncy ball. The system would call a strike if the ball passed through the horizontal light beam as detected by the photocell. This wasn’t too hard to get working, so then the next step was to add a vertical sensor and try to detect dark on more than one sensor at a time. This made the programming quite a lot harder – and I needed my Dad to help me with this part.

Designing the Strike Zone

After building the prototypes it was time to start thinking of ideas for the frame. The two main frame ideas we had were to use wood, and to use PVC Pipes. We chose to use the PVC Pipes because firstly I wanted to make sure that I could get the frame to school for the exhibition. Also, when putting the sensors and lasers on you want them to be adjustable. With wood you would drill a hole and stick in the sensor but if it was off by a tiny bit you could never align them. The PVC Pipes were just a safer option to give me more flexibility.

You can read more about the design process here.

Building the Strike Zone

To wire everything up I had to learn how to solder. If you don’t know soldering is where you use a soldering iron to stick two pieces of wire/metal together. To connect the batteries to the lasers meant soldering wire to and from the breadboard. To keep the wires safe we added some insulation. They were little tubes of rubber that you put over the top of the soldering and open wires. When you heat them up with a hairdryer or something like that it shrinks to the metal.

This post shows some of the work involved in soldering the circuits.

Programming and Testing

To make my machine work it needs to be programmed. I programmed it in Python. It has 5 horizontal sensors and 5 vertical sensors, across from each sensor is a laser. The laser shines light onto each sensor. When a ball goes through one or more of the lasers the sensor will no longer receive light. In the code when a sensor goes dark it checks to see if the other side of sensors also went dark. If the ball hits one horizontal and one vertical it was in the strike zone.

Once everything was wired up and the program was ready it was time to start testing. It was a bit of a shock when I got the battery attached to the lasers and discovered how hard it was to line them up with the sensors. The other major problem was that during testing I figured out that it doesn’t work with a baseball. A thrown baseball travels through too fast and the ball is a bit small. This means that the sensors don’t detect a strike most of the time. I tried using a soccer ball, but still found that the ball was often moving too fast to be detected. Eventually I came up with the idea of using a beach ball. A beach ball is really big and doesn’t pick up much speed so it worked perfectly with the zone. The beach ball was also less likely to break the frame if someone hit it with a bad throw.

Exhibition

At the exhibition setting up my strike zone took quite a long time. Even when we set it up it would easily un-align if the frame got hit. It was frustrating trying to get it set up and then keep it stable.

The exhibition was a lot of fun and both the UIC (Umpire In Chief) and the President of Mount Seymour Little League came to see my project. My project was very popular while it was working – I had a line up at one point! But about half the exhibition time it was unaligned so it wouldn’t work.

I also prepared a Power Point slideshow which I had running in kiosk-mode during the exhibition. This showed the steps that were involved in creating my project.

Conclusion

I am really happy with the way this project turned out even though it didn’t work perfectly. It I had more time, then I am sure I could improve the system. When I started the project I imagined taking it to the park to practice my pitching – but the machine I have right now wouldn’t be stable enough, and wouldn’t see my fast pitches.

The big things I would change if I did the project again, would be to find a better way to build a more solid frame and a system to attach the lasers that was both adjustable and more stable. I would also try and experiment with the sensors and the programming to see if I could make the system more sensitive so that it could detect a real baseball pitch.

I learned a ton of different things during this project (there is a list in the power point). I also learned that creating a reliable automated umpire is very difficult and that we should probably not fire the human umps just yet.

In this Blue Sky I went out of my comfort zone to take on a difficult project that involved a huge amount of work, so I’m happy that it was at least partially successful and that my friends and family had fun with it at the exhibition.