Thursday, December 9, 2010

Simple Color Sensor

Make a color sensor? We can make a color sensor sederhana.Cukup loh use Super Bright LED and LDR (Light Dependent Resistor) or can be replaced with photodioda / phototransistor. Value constraints LDR / photodioda / phototransistor is dependent on the intensity of light on its surface. The greater the intensity of light about it, the LDR resistance is getting smaller and applies also vice versa. So, with the working principle is quite "unique" this component can be utilized as an object color detection. Because of the intensity of light emitted from the LED Superbright and pemantulnya color different for each color, the value of the barrier was also varied. Strand color detection is quite simple, ie, by utilizing strand voltage divider as shown below.
LDR diagram
  If the dipake Photodioda, installation reversed (which get Anode GND). From the above scheme, the output voltage Vo can be calculated using the formula:
Voltage Divider

so, will depend on the size of the voltage Vo provided Vcc (typically 5V hell), so that the output ranges from 0 - Vcc according to the amount of light intensity on the sensor. For the sequel, Vo pin can be processed by using the microcontroller, namely with an ADC facility. Oiya, the value of R1 is the most ideal is stengah of the sensor resistance when in a dark environment (not subject to light). Or can be calculated by:

R1 calculation

Rt = resistance resistors when subjected to bright light
Resistor Rg = resistance when dark


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