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 real 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 oneWire(ONE_WIRE_BUS);

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

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

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

Serial Monitor output

• Temperature readings output to the Serial Monitor.