Saleng Tracker

The Saleng – Tracker module is a compact reflective infrared sensor module designed for detecting the presence or absence of an IR reflective surface (e.g. light or dark line) in front of its optical elements. The module uses the TCRT5000 IR pair while its output is fed to a Schmitt triggered gate producing reliable digital output. It has a Digital Output pin labeled DO and another with an inverted output signal labeled ~DO. DO is high when a reflective surface (e.g. white surface) comes within range and thereby reflecting back the emitter’s IR beam back to the IR receiver on the board. DO is low when no reflective surface (e.g. dark surface) is detected. ~DO’s output is the inverse of DO. The absence of a sensitivity/calibration adjustment potentiometer makes this module easy to use with its digital outputs optimized for dark/light line detection in robotic applications. An Analog Output pin named AO is also available and is tied to the output of the photo diode. This may be useful for distance or obstacle sensing. The tracker module is part of Layad Circuits’ Saleng series of innovation-starter products.

FEATURES
 Detector Type: Phototransistor
 Input Voltage: 3.3V – 5V
 Typical Current Consumption: <40mA
 Peak Current (Vin=5V): 80mA
 Digital Output Effective Distance Range: ~10mm
 Analog Output Effective Distance Range: ~100mm
 Emitter Wavelength: 950nm
 Daylight Blocking Filter
 Digital Output with Inverted Output
 Analog Output
 Small form factor, board dimensions: 15x38mm

TYPICAL APPLICATIONS
 Line Following Robot
 Limit Sensor
 Object Counter
 Speed Mater / Tachometer
 General Obstacle sensing
 Distance Sensing

Pin LabelFunction/Operation/Remarks
Vcc3.3 to 5V input power. A 100mA or
higher power source is recommended.
GndGround pin.
DOSchmitt-triggered digital output. High
when a reflections are detected (e.g.
white surface). Low when no return
wave is detected (e.g. dark surface).
~DOInverse of DO. E.g. ~DO is high when DO
is low.
AOAnalog Output of the photo sensor. The
output voltage is between ground and
Vcc and increases with distance of the
reflective surface from the photo sensor

APPLICATION NOTES
Line Tracing/Line Follower Robot
The Saleng – Tracker module may be used with a microcontroller based mobile robot to quickly detect light and dark surfaces. The module maybe installed under the chassis at a distance of about 1cm from the floor. Only the DO (or the ~DO if you need an inverted logic e.g. low when reflections are detected) is needed in this case. The AO may be left unconnected.

In actual tests, the typical maximum useable distance range is 15 to 20mm. To be on the safe side, a 10mm or lower floor-to-optical sensor distance is advised. Because the digital output come from Schmitt triggered gates, DO and ~DO will readily work with a 5V or 3.3V microcontroller.