The Pololu QTR-1RC reflection sensor carries a single infrared LED (IR) and phototransistor pair. To use the sensor, first charge the output node by applying a voltage to the OUT pin. You can then read the reflectance by subtracting the externally applied voltage from the OUT pin and the time it takes for the output voltage to drop due to the integrated phototransistor. Shorter decay times are an indication of increased reflection. This measurement approach has several advantages, especially when multiple units are used:
- No analog-to-digital converter (ADC) is required.
- Improved sensitivity üvia the voltage divider analog output
- Parallel reading of multiple sensors is possible with most microcontrollers.
The LED current limiting resistor is set to deliver approximately 17 mA to the LED at a VIN of 5 V. The current requirement can be met by some microcontroller I/O lines so that the sensor can be switched up and down via an I/O line to save energy.
- Dimensions: 0.3" x 0.5" x 0.1" (without installed optional pin headers)
- Operating voltage: 5.0 V
- Supply current: 17 mA
- Output format: digital I/O-compatible signal that can be read as a time-controlled high pulse.
- Optimum switching distance: 0.125" (3 mm)
- Maximum recommended switching distance: 0.375" (9.5 mm) (9.5 mm)
- Weight without head pins: 0.008 oz (0.2 g)
|Shipping weight:||0,05 Kg|