RCWL_1601_i2c

An Arduino library for communicating with a RCWL-1601 distance sensor in i2c mode. At the time of this writing, most searches on Google turn up guides for using the RCWL-1601 in UART mode which makes it compatible with other popular ultrasonic sensors.

In UART mode, you signal the "trigger" line which causes the ultrasonic send and then measure the time until the echo line signals that the bounce has been detected.

In I2C mode, the onboard chip does a continuous signal and sense, and an i2c master asks it for the most recent measurements which is returned as 3 bytes encoding the micrometers in big-endian order.

I2C Citizenship Note

This board isn't a good i2c bus citizen as reported by Adafruit. You can make make it work, but basically, you have to call startScanning(), wait long enough for the sonar ping to make it back (500ms maybe), readUm(), stopScanning() and wait long enough for the RCWL-1601 to regather its wits and then you can use the bus for something else.

It's often easier and works better for many applications to put the RCWL-1601 on

Installing

Use the Arduino IDE Library manager to add the source archive zip file main.zip

Usage

#include "RCWL_1601_i2c.h"

I2C_Sonar Sonar(0x57, &Wire);

void setup() {
  Serial.begin(115200);
  Serial.println("RCWL-1601 Sonar in i2c mode");

  Wire.begin();
  Sonar.startScanning();
}

void loop() {
  delay(100);
  long um = Sonar.readUm();
  float cm = um / 10000.0;
  Serial.print(cm);
  Serial.println("cm");
}

See also Examples/DistanceToSerial.ino