You can win this Bingo Machine by stacking balls of the same color in a linear arrangement.For that reason, you need a sensing mechanism that can automatically detect the color of stacked balls.This section introduces how to identify color balls at low cost.

• A color sensor is used for identifying colors.
• To identify colors, the color sensor uses LED light sources in three colors (red, blue, green) for its projection elements. It distinguishes colors based on the light reflection rate of each color by emitting these three colors to a target object.
• To be able to identify subtle color differences, you need relatively expensive sensor/amplifier systems.
• A color sensor distinguishes colors by the following criteria: "Base color match: ON" or "Base color match: OFF." In order to distinguish yellow, black, and white balls, you need three sets of expensive color sensor/amplifier systems.
• The Bingo Machine adeptly utilizes fiber sensors emitting homogeneous light so that the balls in three different colors can be identified at low cost.
• In [Photo 1], two fiber sensors are installed for color ball identification.As you can see, the color of the optical fiber cables is different for the two fiber sensors.
• We chose a fiber sensor that uses red LED as the light source (wavelength of 680 nm) along with another fiber sensor that uses blue LED as the light source (wavelength of 470 nm).When you use these LEDs of two different wavelengths to distinguish three different color balls, choose the appropriate sensitivity setting in order to produce light reflection that can distinguish yellow, black, and white color balls.In this way, all you need is two sets of economical sensor/amplifier systems.
• As you see in this example, you can adopt economical sensor/amplifier systems if you understand and take advantage of the sensing principle to create the sensing function required for an automation device.