Matrix - Ultrasonic Ranger

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Introduction

Ultrasonic Ranger01
  • The Matrix-Ultrasonic_Ranger is used to measure the distance.
  • The module's sensor emits a sound wave, which bounces off a reflective surface and returns to the sensor. Then, using the amount of time it takes for the wave to return to the sensor, the distance to the object can be computed.

Features

  • 5V Power
  • Range: 5 cm - 300 cm,Accuracy: 1 cm
  • One wire gpio
  • PCB Dimension (mm): 20 x 40

超声波PCB

  • Pin Description:
Pin Description
S GPIO
V Supply Voltage 5V
G Ground

Basic Device Operation

  • The sensor emits a 40kHz, 6 mm sound wave, which bounces off a reflective surface and returns to the sensor. The receiver converts ultrasound waves to electrical signals in mV.
  • The master sends a signal to the module starting to emit a sound wave. After the module receives the returned signal it will will generate a high level indicating the elapsed time and the distance will be calculated by distance = (elapsed time * speed of sound)/2.
matrix Ultrasonic Ranger

Applications

Connect to NanoPi M1

Refer to the following connection diagram to connect the module to the NanoPi M1:
Matrix-Ultrasonic_Ranger_nanopi_m1

Connection Details:

Matrix-Ultrasonic_Ranger NanoPi M1
S Pin7
V Pin4
G Pin6

Connect to NanoPi 2

Refer to the following connection diagram to connect the module to the NanoPi 2:
Matrix-Ultrasonic_Ranger_nanopi_2

Connection Details:

Matrix-Ultrasonic_Ranger NanoPi 2
S Pin7
V Pin4
G Pin6

Connect to NanoPi M2 / NanoPi 2 Fire

Refer to the following connection diagram to connect the module to the NanoPi M2/ NanoPi 2 Fire:
Matrix-Ultrasonic_Ranger_nanopi_m2

Connection Details:

Matrix-Ultrasonic_Ranger NanoPi M2
S Pin7
V Pin4
G Pin6

Connect to NanoPC-T2

Refer to the following connection diagram to connect the module to the NanoPC-T2:
Matrix-Ultrasonic_Ranger_NanoPC-T2

Connection Details:

Matrix-Ultrasonic_Ranger NanoPC-T2
S Pin15
V Pin29
G Pin30

Compile & Run Test Program

Boot your ARM board with Debian and copy the matrix code:

$ apt-get update && apt-get install git
$ git clone https://github.com/friendlyarm/matrix.git

If your cloning is done successfully a "matrix" directory will be generated.

Compile and install Matrix:

$ cd matrix
$ make && make install

Run test program:

$ matrix-ultrasonic_ranger

Note: this module is not plug and play therefore before running the module please make sure it is connected to an ARM board.
Here is what you should observe:

The distance is  24 cm

When you place an object in front of the module the distance between the object and the module will be measured and printed.

Code Sample

This Matrix code sample can work with all the ARM boards mentioned in this module's wiki. The name of this code sample is "matrix-ultrasonic_ranger". Here is its source code:

int main(int argc, char ** argv)
{
    int distance = -1;
    int pin = GPIO_PIN(7);
    int board;
 
    if ((board = boardInit()) < 0) {
        printf("Fail to init board\n");
        return -1;
    }
    if (board == BOARD_NANOPI_T2)
        pin = GPIO_PIN(15);
 
    system("modprobe "DRIVER_MODULE);
    if (Hcsr04Init(pin) == -1) {
        printf("Fail to init hcsr04\n");
        goto err;
    }
    if (Hcsr04Read(&distance) != -1) {
        printf("The distance is %3d cm\n", distance);
    } else {
        printf("Faid to get distance\n");
    }
    Hcsr04DeInit();
err:
    system("rmmod "DRIVER_MODULE);
 
    return 0;
}

For more details about this APIs called in this code sample refer to Matrix API reference manual

Resources

Update Log

Feb-23-2016

  • Added the description for "NanoPi 2 branch" in Section 4
  • Added Section 5: Connect to NanoPi 2

June-28-2016

  • Reorganized and simplified wiki