Simulation of the functioning of railway barriers with Micro:bit

Objective of project

There are barriers between a railroad train and a pedestrian or car crossing.

In this project we will realize a system that simulate the operation of automatic barriers for railways trains.

We will design this system using:

• Micro:bit card

• two ultrasonic sensors hc-sr04 for the detection of the arrival of the train.

• two servomotors to lower or raise the barriers

Operation of the barrier controlled by Microbit:

Components required

• Micro:bit card

• HC-SR04 sensor

• Servomotor

• Motor driver GPIO card

• LEDs

• test plate

• connecting wires

• toy train

Assembly:

To do the assembly, we connected:

For the first sound sensor HC-SR04:

• the VCC pin to the 3.3V pin of the Micro:bit

• the Trig pin to the P12 pin of the Micro:bit

• the ECHO pin to pin P13 of the Micro:bit

• the GND pin to the GND pin of the Micro:bit

For the second sound sensor HC-SR04:

• the VCC pin to the 3.3V pin of the Micro:bit

• the Trig pin to pin P14 of the Micro:bit

• the ECHO pin to the P15 pin of the Micro:bit

• the GND pin to the GND pin of the Micro:bit

For the first servomotor:

• red wire: power supply wire to be connected to the 5V terminal of the GPIO card

• brown wire: wire to connect to the GND pin of the Micro:bit

• Yellow: Positioning signal wire connected to Micro: bit pin S1

For the second servomotor:

• red wire: power supply wire to be connected to the 5V terminal of the GPIO card

• brown wire: wire to connect to the GND pin of the Micro:bit

• Yellow: Positioning signal wire connected to Micro:bit pin S2

For LEDs:

• the terminals (-) of the LEDs to GND of the Microbit

• the (+) terminal of the first red LED at P0 of Microbit

• the (+) terminal of the first green LED at P1 of Microbit

• the (+) terminal of the first red LED to P2 of Microbit

• the (+) terminal of the first green LED at P8 of Microbit

Makecode Program

Here is the makecode program which allows you to:

• calculate the distance between the HC-SR04 sensor and the detected object

• raise or lower barriers

• turn LEDs on or off