Wiring Diagram

All distances mentioned before can vary, depending on infra-red transmitting and receiving LEDs used and are mostly affected by the color of the reflecting surface. Black surfaces lower greatly the device sensitivity. Obviously, you can use this circuit in other applications like liquids level detection, proximity devices etc.

Note:

    The infra-red Photo Diode D2, should be of the type incorporating an optical sunlight filter: these components appear in black plastic cases. Some of them resemble TO92 transistors: in this case, please note that the sensitive surface is the curved, not the flat one.
    Avoid sun or artificial light hitting directly D1 & D2.
    If your car has black bumpers, you can line-up the infra-red diodes with the (mostly white) license or number plate.
    It is wiser to place all the circuitry near the infra-red LEDs in a small box. The 3 signaling LEDs can be placed far from the main box at an height making them well visible by the car driver.
    The best setup is obtained bringing D2 nearer to D1 (without a reflecting object) until D5 illuminates; then moving it a bit until D5 is clearly off. Usually D1-D2 optimum distance lies in the range 1.5-3 cm.

TCS230 color sensor is a converter IC to the frequency of light colors. There are two main components of this IC makers, namely photodioda and current to frequency converters. Each color can be drawn from the basic colors. To light, color is the color of the basic constituent Red, Green and Blue, or better known as RGB (Red-Green-Blue).

Photodiode on IC TCS230 array arranged in a 8x8 configuration: 16 Photodiode for red menfilter, 16 Photodiode for the green filter, 16 Photodiode for the blue color filter, and unfiltered Photodiode 16. Photodiode groups which will be used can be arranged through the leg selector S2 and S3.

Photodiode will issue the amount of current is proportional to the level of the basic colors of light that happened. This current is then converted into a signal box with a frequency proportional to the amount of current. Output frequency can be scaled by adjusting the leg selector S0 and S1.

This circuit can sense eight colours, i.e. blue, green and red (primary colours); magenta, yellow and cyan (secondary colours); and black and white. The circuit is based on the fundamentals of optics and digital electronics. The object whose colour is required to be detected should be placed in front of the system.

Note:

    * Potmeters VR1, VR2 and VR3 may be used to adjust the sensitivity of the LDRs.
    * Common ends of the LDRs should be connected to positive supply.
    * Use good quality light filters.