QTR-1A Analog Infrared Sensor Pair (Qty 2)
The QTR-1A reflectance sensor is a single in an inexpensive, small 0.5" x 0.3" module that can be mounted almost anywhere It carries an infrared LED and phototransistor pair. The reflectance measurement is given as analog voltage. 2 qtr-1a sensors are shipped.
The LEDs are controlled by a MOSFET with a gate normally pulled high, which allows the LEDs to be turned off by setting the MOSFET gate to a low voltage . Turning off the LEDs can be advantageous to limit power consumption when the sensors are not in use or to vary the effective brightness of the LEDs with PWM control. LED current limiting resistors for 5 V operation are arranged in two stages; This allows a simple tap bypass to enable operation at 3.3 V. LED current is approximately 20-25 mA, reducing the total board consumption to less than 100 mA.
Schematic Diagram of the Module
Specifications
- Dimensions: 0.3" x 0.5" x 0.1" (without optional header pins installed)
- Operating voltage: 5.0 V
- Supply current: 17 mA
- Output format: analog voltage
- Output voltage range: 0 to supplied voltage
- Optimal sensing distance: 0.125" (3 mm)
- Recommended maximum detection distance: 0.25" (6 mm)
- Weight without header pins: 0.008 oz (0.2 g)
Interfacing with QTR-1A Outputs
There are several ways to interface with QTR-1A outputs:
- Voltages Use a microcontroller's analog-to-digital converter (ADC) to measure it.
- Use a comparator with adjustable thresholds to convert each analog voltage into a digital (i.e., black/white) signal that can be read by a microprocessor's digital I/O line.
- Connect each output directly to a microprocessor's digital I/O line and rely on its internal comparator.
Pololu AVR library provides functions that make it easy to use these sensors with robot controllers. For more information QTR library command You can check the section. For the QTR-1A Arduino library,
click
Set Content
This module #2 screw It has a single mounting hole (screw not included); In case this mounting hole is not needed, this part of the PCB can be grounded to make the unit even smaller. Each package of two infrared sensors includes a straight male header and a right-angle male header, allowing you to mount them in the orientation you choose.
Pololu QTR Sensors Application Notes
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