User manual

Robotics experiment with PIC microcontroller l 71
Line tracking or following is a popular activity in any Robotics activity. The purpose
of this activity is to learn about how to interface analog sensor. In Robo-PICA robot kit, it
comes with a pair of Infrared reflector sensor for this activity. Add senses to the Robo-PICA
so that it can detect and move following the line, by using the IR Reflector Sensor. Two IR
Reflector Sensors will be installed at the bottom of the Robo-PICA so that it can detect
both white and black lines.
6.1 ZX-03 Infrared Reflector
The heart of this sensor is TCRT5000 reflective object sensor. It is designed for close
proximity infrared (IR) detection. There’s an infrared diode behind its transparent blue
window and an infrared transistor behind its black window. When the infrared emitted by
the diode reflects off a surface and returns to the black window, it strikes the infrared
transistor’s base, causing it to conduct current. The more infrared incident on the transistor’s
base, the more current it conducts.
When used as an analog sensor, the ZX-03 can detect shades of gray on paper
and distances over a short range if the light in the room remains constant.
The suitable distance from sensor to line or floor is during 3 to 8 mm. The output
voltage is during 0.1 to 4.8V and digital value from10-bit A/D converter is 20 to 1,000.
Thus, ZX-03 will suitable to apply to line tracking sensor.
Figure 6-1 : ZX-03 Infrared Reflector information
10k
TCRT5000
510
+V
GND
OUT
Infrared Reflector
Signal connector
Chapter 6
Line following mission