Arduino photogate shield

So I set out to make my own photogate with Arduino and got some success. I then tried to make my design more robust for students. The breadboard version is not safe enough or convenient for labs. I decided to make a printed circuit board so there won’t be any loose wires that would be pulled out or even short the board. Also I want to stack the board on top of the Arduino, as a shield. I made this design back during the summer of 2010. This is a basic design with connections to photogates via stereo audio cables, a few buttons and an LCD connector for future development.

This is the assembled picture:

Here I powered it on with an LCD to display some information:

This is the schematic diagram:

This is the PCB design:

I will add more detail of the design and testing results in a later post. Time to grade papers.