5. Expansion-Sonar:bit¶

5.1. Introduction¶

Sonar:bit is a 3-wire ultrasonic module with the working voltage between 3-5V. It is available to be used to 3.3V or 5V micro-controller system. With only one 3-wire(GVS) cable, it can work properly. Compared to the normal 4-wire ultrasonic module, it has saved one IO port.

The measurement range of sonar:bit is 4cm-400cm. It can output stable and accurate measurement data with ±1cm tolerance only.

It can connect to the Ring:bit with an expansion board.

../../_images/sonar_01.png

5.2. Features¶

Input voltage:3V~5V and can be driven by micro:bit directly.

Standard 3-wire GVS connecotr, which occupies 1 IO port only.

5.3. Parameter¶

| Item | Parameter | Note | | — | — | — | | Name | Ring:bit Car v2 Sonar:bit | | | SKU | EF04089 | | | Working Voltage | DC 3-5V | | | Connections | 3pin GVS Connection || | Output signal | Analog | | | Measurement | 4~400cm | | | Size | 40.60×51.60mm | | | NW | 12g | |

5.4. Outlook and Dimensions¶

../../_images/sonar_02.png

5.5. Quick to Start¶

Hardware Connections¶

Connect the acrylic transition board to the back board with the rivets.

../../_images/sonar_03.png

Connect the Sonar:bit to the other side of the acrylic transition board with rivets.

../../_images/sonar_04.png

Connect the Sonar:bit to the Ring:bit breakout board with a 3-pin wire.

../../_images/sonar_05.png

5.6. Programming¶

Preparation for Programming: Info

Samples Code¶

# Import modules that we need
import board
from ringbit import *

# Set the pins of both wheels
ringbit = Ringbit(board.P1, board.P2)

# Change the speed in accordance with the distances detected by the sonar:bit
while True:
    if ringbit.get_distance(board.P0, Unit.cm) > 20:
        ringbit.set_speed(100, 100)
    else:
        ringbit.set_speed(0, 0)

Details of the program¶

1.Import the modules that we need. board is the common container, and you can connect the pins you’d like to use through it; ringbit module contains classes and functions for Ring:bit smart car operations.

import board
from ringbit import *

2.Set the pins of the servos

ringbit = Ringbit(board.P1, board.P2)

3.While true, set the speed to be controlled by the distance value given by the sonar:bit

while True:
    if ringbit.get_distance(board.P0, Unit.cm) > 20:
        ringbit.set_speed(100, 100)
    else:
        ringbit.set_speed(0, 0)

5.7. Result¶

The Ring:bit car drives normally when there are no obstacles, stops when there are obstacles, and continues to drive when the obstacles leave.