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3.2.3 Infrared Tracing
3.2.3.1 Introduction of Infrared Tracing Sensor
After infrared obstacle avoidance, let us learn the infrared tracing, their nature of work is the same,
using basically the same module, just in different ways, to achieve different functions.
we study, we have to pay attention to the color of the line we trace (the black line or white line), if your floor
is black, you should trace the white line (pasting white line on the floor); if it is white, then you should trace
the black line (pasting black line on the floor); you just need to make a distinct difference between the track
and the ground environment.
In the "Hummer-Bot" car, we use the TCRT5000 sensor as tracing module, which consists of an
infrared emitting diode and an NPN infrared photoelectric transistor. The physical map is shown in
Fig.3.2.16.
3.2.3.2 Working Principle
In the above, we talked about two patterns of tracing-the white line and the black line. In fact, either the
black line or the white line, we usually adopt the infrared detection method.
Infrared detection method means that different objects with different colors have the different infrared
reflection characteristics. The car launches the infrared to the ground continually during driving process, the
infrared receiving tube will be in a shutdown state and the output of the module is low level when the
emitted infrared is not reflected or the reflected infrared is not strong enough, and indicating diode will be
off; when the diffuse reflection occurred on a white floor, the intense reflected infrared will be received by
the receiving tube on the car, the photosensitive triode will be saturated, the output end of the module is high
level and the indicating diode will light.
Figure .3.2.16 Physical Map of the Module
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In this section when
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