Since Cameron Hoerig is an engineering student at the University of Cincinnati, the idea of building a typical beer pong table was out of the question. "I'm an electrical engineering student, so I should have a table that stands out," says Hoerig.
He built an interactive table. On either end of the table - where the cups stand - there are 10 LED rings composed of eight LEDs each. In the middle of each ring there's a photocell. The Ping-Pong ball triggers the sensors and the gadget's software rotates the LEDs, giving the illusion of a light spinning around the cup.
It's impossible to read the documentation but I'm responding to your problem with inconsistent linearity of photocells. Yes, photocells are imprecise and non-linear. Much of the voltage appears across the limiting resistor. Consider putting a transistor as a constant current source in series with photocells, eliminating the resistor. The voltage across the transistor will be a consistent two diode drops. That way, all the voltage change appears across the photocell. I hope I have understood your problem.
At the Design News webinar on June 27, learn all about aluminum extrusion: designing the right shape so it costs the least, is simplest to manufacture, and best fits the application's structural requirements.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This radio show will show what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.