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• Electronic Signs and Signals
Figure 1: Application of sensor in smartphones[2]
As shown in figure 1, the APDS-9003 sensors can be used as Ambient Light Detection sensor. They are responsible for dimming the light with respect to the surroundings light. They are also responsible to black out the screen during a call. This helps to save the power of the device and increase the life of the screen and power source.
Relative Spectral Response vs Wavelength
Figure 12: Relative Spectral Response Vs wavelength[1]
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Light sources consists of ac noise frequencies. For example a flourescent light consists of about 100Hz ac noise frequency. A low pass filter is required to be added in the circuit parallel with the load resistor to decrease the ripple.
Figure 23: Electronic configuration for APDS-9003[1]
As shown in figure 23, The 3V Vcc is supplied to the sensor in pin 1 and pins 2 to 5 are not connected. Pin 6 is the output pin. When a light source strikes the sensor it produces photo current. The current through load resistor creates the analog voltage output. The capacitor in parallel with the RL filters the noise and the filtered signal is converted to digital format in our electronic devices using A/D converter or a microcontroller.
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- APDS-9003, Avago Technologies datasheet
URL: http://www.avagotech.com/docs/AV01-0238EN [Online], Last Accessed: 10.4.2014 - Mobile phones- much more than just telephones, Avago Technologies
URL: http://www.sekorm.com/Ectm/19789 [Online], Last Accessed: 10.4.2014
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