The VL6180 works by measuring the time it takes for light to bounce off of a distant surface. This is a more accurate method than using reflected light intensity or a reflected angle measurement. It is available from Sparkfun.

Hello World

//updates the pc terminal with range readings twice a second
#include "VL6180.h"
#include "mbed.h"

VL6180 rf(p9, p10); //I2C sda and scl
Serial pc(USBTX, USBRX); //USB serial

int main() {
    float reading;
    while(1) {
        reading = rf;
        pc.printf("Read %4.1f cm\n", reading);
        wait(0.5);
    }
}

Library

Pinout

Images

Connection of breakout board to mbed.

Screen capture showing output of hello world program.

Usage

To use the VL6180 breakout board, connect it to mbed according to the pinout above. Then, create a VL6180 object in the C++ code. The constructor automatically handles initialization of the device. The read() function returns a float ranging from 0.0cm to 25.5cm according to the distance the range finder read. The maximum range is approximately 20cm. When this distance is reached, the read() function will return 25.5cm instead.

Notes

Although the VL6180 chip requires 2.8V to work properly, the Sparkfun breakout board includes a 2.8V voltage regulator. This allows the board to run off of mbed's 3.3V supply. The breakout board also includes the pull-up resistors necessary for I2C to work properly.

How It Works

Additional Resources

VL6180 Datasheet

VL6180 Application Note

Breakout board schematic