Arduino library for the TCRT5000 reflective optical sensor (IR).

Experimental

The TCRT5000 sensor is an infrared reflective sensor. This library is written to use with a TCRT5000 breakout's analog output and handle a threshold in software.

These breakouts have typical two outputs, a digital and an analog one. The analog output returns a "raw" signal strength. The digital output has a threshold level depending on a potentiometer which is typically set once.

The library allows to set a threshold in software and compare if the raw signal is either above or below this set threshold. As the threshold is set in software it can be changed runtime. This can be useful to adapt e.g. to changing lighting conditions.

As always feedback is welcome.

Uses analog output.

• https://github.com/RobTillaart/PIR

#include "TCRT5000.h"

• TCRT5000(uint8_t analogPin)
• int read()
• int lastRead()

Default threshold TCRT5000_DEFAULT_THRESHOLD (500). This is about 50% of the UNO R3 ADC, so you might need to change this.

• void setThreshold(int threshold) idem
• int getThreshold() returns set value or the default.
• bool aboveThreshold() reads the sensor and returns true is above the set (or default) threshold.
• bool belowThreshold() reads the sensor and returns true is below or equal to the set (or default) threshold.

• improve documentation

• add examples

• compare to threshold, (use case?)
  • int absoluteTH() == read() - threshold;
  • float relativeTH() == ((read() - threshold) x 1.0)/ threshold;
  • float percentageTH() == 100 x relativeTH();

• convert to distance
  • depends on a lot of factors.

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Thank you,