122-28176 Parallax Inc, 122-28176 Datasheet - Page 94

• Manufacturer Part Number: 122-28176
• Description: GUIDE STUDENT PROCESS CONTROL
• Manufacturer: Parallax Inc

Specifications of 122-28176

• Accessory Type: Manual
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Propeller Education (PE) Kit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

Some examples of optical sensors include:
This chapter uses a close-range IR optical sensor to demonstrate operation and signal
conditioning. The sensor is used as part of sequential processes for detection and event
input.
ACTIVITY #1: CONNECTING AND TESTING THE OPTO-REFLECTIVE
SWITCH
The QRB1114 shown in Figure 4-1 is an opto-reflective switch. The actual switching
circuit is a phototransistor. Light hitting the transistor causes a current flow in the base-
emitter, which in turn causes an amplified current flow in the collector-emitter. The
package also contains an infrared LED to use as a light source (emitter). The LED emits
infrared light (IR) not visible to the human eye, and the phototransistor is most sensitive
to this wavelength of light.
In this figure, (E) is the emitter of the phototransistor, and (C) is the collector. (A) stands
for the anode of the IR LED, and (K) marks the cathode.
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Using a light beam to detect presence of an object or person at a moderate
distance (several feet).
Using an emitter and detector pair for very close detection, such as motion of
your mouse, the passing of paper in a printer, or the opening of a printer cover.
Using reflected light to measure the rotation of a shaft.
Using light to transmit data at a reasonably close range (TV remote) or perhaps a
very long range (fiber-optic telecommunications).
Figure 4-1
Opto-Reflective
Switch