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.
The Beam Store from Suitable Technologies is managed by remote workers from places as diverse as New York and Sydney, Australia. Employees attend to store visitors through Beam Smart Presence Systems (SPSs) from the company. The systems combine mobility and video conferencing and allow people to communicate directly from a remote location via a screen as well as move around as if they are actually in the room.
An MIT research team has invented what they see as a solution to the need for biodegradable 3D-printable materials made from something besides petroleum-based sources: a water-based robotic additive extrusion method that makes objects from biodegradable hydrogel composites.
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