Smart Cities - Tiny House at Home

Raspberry Pi OS

• Starting with a fresh install of the Raspberry Pi Debian Bookworm OS with desktop (64 bit).
• Use the Raspberry Pi Imager to install the OS on a 16MB micro SD card.
• Complete the set up and updates on the Raspberry Pi.

Install the Python IDE (not thonny) and the MQTT broker

• Open the Terminal and enter these commands

sudo apt update
sudo apt -y full-upgrade 
sudo apt install -y idle3 arduino

Install Virtual Environment

• These days Python must run in a virtual environment so that each user gets their own Python
• The virtual environment has to be activated before each use
• The linux prompt then changes from:
• <username>@home:~ $ to (env) <username>@home:~ $

• Create a virtual environment for Python called env in your /home/<username> directory.
  • In Linux (and other operating systems), a virtual environment is an isolated Python environment that allows you to install and manage Python packages separately from the system-wide Python installation.
  • This ensures that your Python projects have their own dependencies and versions of libraries without affecting or being affected by other projects or the global Python environment.
• Enter the commands in the Terminal.

cd ~
python3 -m venv env

• Activate the virtual environment with the commands.

cd ~/env
source bin/activate

• Dectivate the virtual environment with the command.

deactivate

Configure the Python Idle3 shortcut to auto-activate the Python virtual environment

• Click Raspberry | Programming
• Right Click IDLE (using Python-3.11)
• Click Properties | Desktop Entry
• In the Command: field enter

/home/<username>/env/bin/python3.11 -m idlelib.idle

Arduino Uno - One Wire Temperature sensor

Frizing - Circuit diagram

• In this circuit diagram the data line is connected to pin 2.
• In the Arduino code below the data line is connected to pin 4.

One Wire Library installation

• Select Sketch > Include Library > Manage Libraries
• Wait for libraries to update. This may take 1-2 minutes.
• In the search bar enter onewire and press Enter.

• Install the One Wire library.
• Use the One wire library with the author Paul Stoffregen

• In this example the onewire library version 2.3.7 was installed.

Dallas Temperature Library installation

• After installing the onewire library now enter Dallas as the search term.

• In this instance version 3.9.0 of the DallasTemperature library was installed.

Arduino Uno Code

#include <OneWire.h>
#include <DallasTemperature.h>

// Data wire is conntec to the Arduino digital pin 4
#define ONE_WIRE_BUS 4

// Setup a oneWire instance to communicate with any OneWire devices
OneWire sensor_1_wire(ONE_WIRE_BUS);

// Pass our oneWire reference to Dallas Temperature sensor 
DallasTemperature sensor1(&sensor_1_wire);

void setup(void)
{
  // Start serial communication for debugging purposes
  Serial.begin(9600);
  // Start up the library
  sensor1.begin();
}

void loop(void){ 
  // Call sensor1.requestTemperatures() to issue a global temperature and Requests to all devices on the bus
  sensor1.requestTemperatures(); 
  
  Serial.print("Celsius temperature: ");
  // Why "byIndex"? You can have more than one IC on the same bus (pin). 0 refers to the first IC on the wire
  Serial.println(sensor1.getTempCByIndex(0)); 
  delay(1000);
}

Serial Monitor output

• Temperature readings output to the Serial Monitor.

Setting up VNC Server

Check if VNC is Already Installed

In recent versions of Raspberry Pi OS, VNC comes pre-installed but might be disabled by default.

• Check Installation:
• Open a terminal on your Raspberry Pi.
• Run:

vncserver --version

If VNC is installed, it will display the version. If not, install it (see step 3).

Enable VNC on Raspberry Pi

• Open the Raspberry Pi Configuration Tool:
• GUI: Go to Start Menu > Preferences > Raspberry Pi Configuration.
• CLI: Run:

sudo raspi-config

• Navigate to:
• Interface Options > VNC > Enable
• Confirm and exit the configuration tool.
• Verify that the VNC service is running:

systemctl status vncserver-x11-serviced.service

If not running, start it:

sudo systemctl start vncserver-x11-serviced.service

Install VNC (if not installed)

If VNC isn't pre-installed:

• Update the package list:

sudo apt update

Install VNC Server:

sudo apt install realvnc-vnc-server

Connect to the Raspberry Pi Using VNC Viewer

Find the Raspberry Pi’s IP Address:

hostname -I

• Note the first IP address (e.g., 192.168.1.100).
• Install VNC Viewer on your client device:
• Download VNC Viewer for Windows, macOS, or Linux.
• Open VNC Viewer on your client device and enter the Raspberry Pi’s IP address (e.g., 192.168.1.100).
• Log in with your Raspberry Pi's credentials:

Username: pi
Password: (default is raspberry, or your custom password).

Optional: Configure VNC

• Resolution Adjustment:

Edit /boot/config.txt to set a virtual desktop resolution:

sudo nano /boot/firmware/config.txt

Add or modify:

hdmi_force_hotplug=1
hdmi_group=2  # Set to 2 for DMT (monitor resolutions)
hdmi_mode=9   # Example: 800x600 @ 60Hz

This sets a resolution of 800x600. Save and reboot:

sudo reboot

hdmi_force_hotplug=1

• Forces the Raspberry Pi to output HDMI signals even if no HDMI display is detected at boot.
• This is essential when you're using VNC without a physical monitor connected.

Now you can access your Raspberry Pi 4 from any device on the same network!

Setting up VNC Viewer

To install a VNC client on a Raspberry Pi 4 and use it to access another Raspberry Pi with a VNC server already running, follow these steps:

Install VNC Viewer on the Raspberry Pi 4

• Open a terminal on your Raspberry Pi 4.
• Install the RealVNC Viewer (the VNC client):

sudo apt update
sudo apt install realvnc-vnc-viewer

Confirm the installation by running:

vncviewer --version

This should display the version of VNC Viewer installed.

Get the IP Address of the Remote Raspberry Pi

• On the Raspberry Pi with the VNC server running, open a terminal.
• Find its IP address by running:

hostname -I

Note the first IP address (e.g., 192.168.1.102).

Use VNC Viewer to Access the Remote Raspberry Pi

Launch VNC Viewer on your Raspberry Pi 4 by typing:

vncviewer

• In the VNC Viewer window:
• Enter the IP address of the remote Raspberry Pi (e.g., 192.168.1.102).
• Click Connect.
• Log in to the remote Raspberry Pi:
• Enter the username and password of the remote Raspberry Pi.
• After successful authentication, you will see the remote Raspberry Pi's desktop.

Save Connection for Future Use

• VNC Viewer allows you to save connections for easy access later.
• Click File > New Connection in VNC Viewer and save the remote Pi's details.

Setting Static IP Address on Raspberry Pi

To set a fixed IP address on a Raspberry Pi using the Advanced Options > Edit Connections graphical interface, follow these steps:

Open the Network Connections Settings

• On your Raspberry Pi, open the desktop environment.
• Click on the network icon in the top-right corner of the screen (usually looks like Wi-Fi or two arrows).
• Select Advanced Options > Edit Connections.

Select the Connection to Configure

• In the Edit Connections window, you'll see a list of network connections.
• Find the connection you want to configure (e.g., your Ethernet or Wi-Fi connection).
• Select the connection and click Edit.

Set a Static IP Address

• Navigate to the IPv4 Settings tab.
• Change the Method from Automatic (DHCP) to Manual.
• Click the Add button to input the following details:
• Address: The desired static IP address (e.g., 192.168.1.100).
• Netmask: The subnet mask (usually 255.255.255.0 for home networks) or enter 24which is equivalent to 255.255.255.0.
• Gateway: The IP address of your router (e.g., 192.168.1.1).
• Enter the DNS server(s) under the DNS Servers field, separated by commas if multiple, or just enter the IP address of the router.
  • For example, 8.8.8.8, 8.8.4.4 (Google DNS) or your router's IP address.

Save and Apply

• Click Save to save your changes.
• Restart the network connection:
• Disable and re-enable the connection from the network icon, or
• Reboot the Raspberry Pi for the changes to take effect.

Verify the Static IP

• Open a terminal and check your IP address:

hostname -I

Ensure it matches the static IP you configured. Test network connectivity:

ping 8.8.8.8

This will verify that your Pi can reach the internet.

Notes

• Choose a static IP outside your router's DHCP range to avoid conflicts with dynamically assigned IPs. You can find the range in your router's settings (typically via 192.168.1.1 in a browser).
• If you encounter connectivity issues, double-check the gateway and DNS server settings.

Interpreting Data from Arduino on Raspberry using Python

Installing python libraries

• Install python libraries in the Virtual Environment.
• Enter the project folder env
• Activate the virtual environment

source bin/activate

Enter the following command to install the serial, datetime and requests python libraries.

pip3 install serial datetime requests

Python code to read serial data from the Arduino

• Open the Arduino IDE and enter the following code.
• Save the file as serialReceive.py
• Run the code.

import serial
import time

# Replace '/dev/ttyUSB0' with your device's port
ser = serial.Serial('/dev/ttyUSB0', 9600, timeout=1)
time.sleep(2)  # Wait for Arduino to reset

while True:
    if ser.in_waiting > 0:
        data = ser.readline().decode('utf-8').strip()
        print("Received:", data)