# Test Raspberry Pi 5 GPIO pins for smart home devices

## In this learning path

- [Introduction](https://learn.arm.com/learning-paths/embedded-and-microcontrollers/raspberry-pi-smart-home/)
- [Run LLMs locally on Raspberry Pi 5 for Edge AI](https://learn.arm.com/learning-paths/embedded-and-microcontrollers/raspberry-pi-smart-home/1-overview/)
- [Set up software dependencies on Raspberry Pi 5 for Ollama and LLMs](https://learn.arm.com/learning-paths/embedded-and-microcontrollers/raspberry-pi-smart-home/2-software-dependencies/)
- [Test Raspberry Pi 5 GPIO pins for smart home devices](https://learn.arm.com/learning-paths/embedded-and-microcontrollers/raspberry-pi-smart-home/3-test-gpio/)
- [Build and Run a Smart Home Assistant on Raspberry Pi 5 with LLMs](https://learn.arm.com/learning-paths/embedded-and-microcontrollers/raspberry-pi-smart-home/4-smart-home-assistant/)
- [Next Steps](https://learn.arm.com/learning-paths/embedded-and-microcontrollers/raspberry-pi-smart-home/_next-steps/)

## Overview
The next step is to test the GPIO functionality. In this section, you configure an LED light to simulate a smart home device.

## Verify GPIO setup on Raspberry Pi 5
Gather your electronic components. Connect the anode (long leg) of an LED in series with a 220Ω resistor to GPIO 17 (physical pin 11). Connect the cathode (short leg) to a ground (GND) pin.

See the image below for the full setup:

![Raspberry Pi connected to a breadboard with a green LED and jumper wires](https://learn.arm.com/learning-paths/embedded-and-microcontrollers/raspberry-pi-smart-home/pin_layout.jpg)
Raspberry Pi connected to a breadboard with a green LED and jumper wires

Create a Python script named `testgpio.py`:

```
cd $HOME/smart-home
vim testgpio.py
```

Add the following code to the file:

```
#!/usr/bin/env python3
import time
from gpiozero import Device, LED
from gpiozero.pins.lgpio import LGPIOFactory

# Set lgpio backend for Raspberry Pi 5
Device.pin_factory = LGPIOFactory()

# Set up GPIO pin 17
pin1 = LED(17)

try:
    while True:
        pin1.toggle()  # Switch pin 17 state
        time.sleep(2)  # Wait 2 seconds
except KeyboardInterrupt:  # Ctrl+C pressed
    pin1.close()  # Clean up pin 17
```

Run the script:

```
python testgpio.py
```

The LED should blink every two seconds. If you observe this behavior, your GPIO setup works correctly.

### Troubleshooting
If you run into issues with the hardware setup, check the following:
- Fix missing dependencies with:
    ```
    sudo apt-get install -f
    ```
- If you encounter GPIO permission issues, run Python scripts with `sudo` or add your user to the `gpio` group. Don’t forget to log out for the changes to take effect:
    ```
    sudo usermod -a -G gpio $USER
    ```
- Double-check wiring and pin numbers using the Raspberry Pi 5 pinout diagram
- Ensure proper LED and resistor connections
- Verify GPIO enablement in `raspi-config` if needed
- Use a high-quality power supply

With GPIO pins working, you can now move on to the next section to interact with devices using language models and the user interface.