Obstacle IR Sensor with Smart Pi One

In this guide, we will demonstrate how to display a message when an obstacle is detected by an IR obstacle sensor connected to the Smart Pi One, using the SmartPi-GPIO library.

We will cover the following methods: - CLI commands - Python script

Required Materials

• Smart Pi One
• IR obstacle sensor
• Connecting wires
• Breadboard (optional for easier connections)

Wiring Diagram

The IR obstacle sensor is connected to GPIOG11 (Pin 7) as the input pin for detecting obstacles. When an obstacle is detected, the sensor outputs a LOW signal (0).

Pin Number	Pin Name	Function
1	3.3V	Power Supply
7	GPIOG11	Obstacle Sensor Input
6	GND	Ground

Prerequisites: Configuration of smartpi-gpio

To install SmartPi-GPIO on your Smart Pi One, follow these steps:

1. Update system:

sudo apt update 
sudo apt-get install -y python3-dev python3-pip libjpeg-dev zlib1g-dev libtiff-dev
sudo mv /usr/lib/python3.11/EXTERNALLY-MANAGED /usr/lib/python3.11/EXTERNALLY-MANAGED.old

1. Clone the repository:

git clone https://github.com/ADNroboticsfr/smartpi-gpio.git
cd smartpi-gpio

1. Install the library:

sudo python3 setup.py sdist bdist_wheel
sudo pip3 install dist/smartpi_gpio-1.0.0-py3-none-any.whl

1. Activate GPIO interfaces:

sudo activate_interfaces.sh

Displaying a Message via CLI

You can detect obstacles using the CLI and print a message accordingly.

Steps:

1. Configure the sensor pin as input:

sudo gpio 7 mode in pull-up

1. Read the sensor state:

sudo gpio 7 read

1. Example to display a message: Use a loop to continuously check the sensor status and display a message when an obstacle is detected:

while true; do
  value=$(sudo gpio 7 read)
  echo "Obstacle IR value: $value"
  sleep 1
done

This will display the current value read by the Obstacle IR every second..

Using Python

Displaying a Message with Python

With SmartPi-GPIO and Python, you can write a simple script to detect obstacles and display a message.

Steps:

1. Create a Python file:

nano ir_sensor_message.py

1. Write the following code:

from smartpi_gpio.gpio import GPIO
import time

# Initialize GPIO instance
gpio = GPIO()

# GPIO pin number for the IR sensor (GPIOG11)
sensor_pin = 7

# Configure the sensor pin as input with pull-up resistor
gpio.set_direction(sensor_pin, "in", "pull-up")

print("Monitoring for obstacles...")

while True:
    # Read the sensor state
    sensor_state = gpio.read(sensor_pin)

    if sensor_state == '0':  # If an obstacle is detected
        print("Obstacle Detected!")
        break

    time.sleep(0.1)

1. Save and exit (CTRL + X, Y, and Enter).

2. Run the Python script:

sudo python3 ir_sensor_message.py

When an obstacle is detected, the message "Obstacle Detected!" will be displayed.