Category Archives: Python

Controlling Brightness of Arduino LED Remotely Using PyQt and WiFi

June 25, 2025 admin

In this lesson we will use PyQt5, UDP and WiFi to control the brightness of an Arduino LED circuit remotely. The PyQt generates a constantly updating sin wave, which it plots on a PyQt graph, and then transfers the brightness in real time to the arduino project. This lesson teaches many important skills including UDP, WiFi, PyQt5, Python, Arduino and LEDs.

When using the breadvolt, or any battery power supply on a breadboard project, do not turn the power supply on while the Arduino is connected to USB, as you could generate voltage conflicts. It is an either or. If the USB is connected, the power supply should be OFF. The schematic for the arduino circuit is shown below:

Schematic of our Arduino Uno R4 Wifi connected to an RGB LED

In the video, we develop code for the server, on the arduino, and the client, running in Python on the desktop. We present the code below for your convenience.

This is the Server code for the Arduino:

#include <WiFiS3.h>
#include "secrets.h"
WiFiUDP udp;
int PORT = 12345;
String myString;
String stringArray[10];
String response = "ACK";
int redPin=9;
void setup() {
  Serial.begin(9600);
  pinMode(redPin,OUTPUT);
  Serial.print("Connecting to ");
  Serial.println(mySSID);
  WiFi.begin(mySSID, myPASS);
  while (WiFi.status() != WL_CONNECTED) {
    delay(100);
    Serial.print(".");
  }
  Serial.println("\nConnected to WiFi");
  Serial.println(WiFi.localIP());
  udp.begin(PORT);
  Serial.print("UDP Server started on port ");
  Serial.print(PORT);
  // put your setup code here, to run once:
}
void splitString() {
  int startIndex = 0;
  int indexCount = 0;
  int i;
  int j;
  myString = myString + ':';
  for (i = 0; i < myString.length(); i = i + 1) {
    if (myString[i] == ':') {
      stringArray[indexCount] = myString.substring(startIndex, i);
      indexCount = indexCount + 1;
      startIndex = i + 1;
    }
  }
}

void loop() {
  // put your main code here, to run repeatedly:
  if (udp.parsePacket()) {
    myString = udp.readStringUntil('\n');
    splitString();
    analogWrite(redPin,stringArray[0].toInt());
  }
}

#include <WiFiS3.h>

#include "secrets.h"

WiFiUDP udp;

int PORT = 12345;

String myString;

String stringArray[10];

String response = "ACK";

int redPin=9;

void setup() {

Serial.begin(9600);

pinMode(redPin,OUTPUT);

Serial.print("Connecting to ");

Serial.println(mySSID);

WiFi.begin(mySSID, myPASS);

while (WiFi.status() != WL_CONNECTED) {

delay(100);

Serial.print(".");

}

Serial.println("\nConnected to WiFi");

Serial.println(WiFi.localIP());

udp.begin(PORT);

Serial.print("UDP Server started on port ");

Serial.print(PORT);

// put your setup code here, to run once:

}

void splitString() {

int startIndex = 0;

int indexCount = 0;

int i;

int j;

myString = myString + ':';

for (i = 0; i < myString.length(); i = i + 1) {

if (myString[i] == ':') {

stringArray[indexCount] = myString.substring(startIndex, i);

indexCount = indexCount + 1;

startIndex = i + 1;

}

void loop() {

// put your main code here, to run repeatedly:

if (udp.parsePacket()) {

myString = udp.readStringUntil('\n');

splitString();

analogWrite(redPin,stringArray[0].toInt());

}

You will need to open a new tab, and save the following code as “secrets.h” with the program above.

#define mySSID "Your WiFi Name"
#define myPASS "Your WiFi Password"

1 2	#define mySSID "Your WiFi Name" #define myPASS "Your WiFi Password"

On the Python side, this is the Client code:

import pyqtgraph as pg
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
from PyQt5.QtGui import QGuiApplication
import sys
from math import sin,pi
import time
import socket
 
# Arduino’s IP address (from Arduino Serial Monitor)
HOST = "192.168.88.120"  # Use Your Arduino's IP. It will print when
                        #You Run the Arduino Server Program
PORT = 12345            # Must match Arduino’s UDP port
 
# Create a UDP socket
mySocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
mySocket.settimeout(5.0)  # 5 seconds timeout for responses

Period = 5
frequency = 1/Period
numPoints = 500
timeStep = Period/numPoints
redData = [0]*numPoints
timeData =[0]*numPoints

app = QApplication([])
window = QMainWindow()
window.setWindowTitle("Red Sine Wave Graph")
window.setGeometry(100,100,800,600)

screens =QGuiApplication.screens()
window.move(screens[1].geometry().x() +100,screens[1].geometry().y() +100)

widgetContainer =QWidget()
window.setCentralWidget(widgetContainer)

mainLayout = QVBoxLayout(widgetContainer)

plotWidget = pg.PlotWidget()
plotWidget.setLabel("left", "y=sin(2*Pi*f*t")
plotWidget.setLabel("bottom", "Time (s)")
plotWidget.setTitle("My Fine Sin Wave")
plotWidget.addLegend()
mainLayout.addWidget(plotWidget)

for i in range(numPoints):
    t = i * timeStep
    timeData[i] = t
    redData[i] = sin(2*pi*frequency*t)

redPlot = plotWidget.plot(timeData,redData, pen=pg.mkPen("r", width=3), name="Red")
tStart = time.perf_counter()
def updateGraph():
    global t,tStart,frequency
    t = t +timeStep
    r= sin(2*pi*frequency*t)
    redWrite = int((r*255 + 255)/2)
    myData= str(redWrite)+'\n'
    myDataEncoded=myData.encode()
    mySocket.sendto(myDataEncoded, (HOST,PORT))
    for i in range(numPoints -1):
        redData[i] = redData[i+1]
        timeData[i] = timeData[i+1]
    redData[numPoints - 1] = r
    timeData[numPoints -1] = t
    redPlot.setData(timeData,redData)
    if redData[0] <=0 and redData[1] > 0:
        measuredPeriod = time.perf_counter() - tStart
        print("Measured Period: ",measuredPeriod)
        tStart = time.perf_counter()

timer = QTimer()
timer.timeout.connect(updateGraph)
timer.start(int(timeStep*1000))

window.show()
sys.exit(app.exec_())

import pyqtgraph as pg

from PyQt5.QtWidgets import *

from PyQt5.QtCore import *

from PyQt5.QtGui import QGuiApplication

import sys

from math import sin,pi

import time

import socket

# Arduino’s IP address (from Arduino Serial Monitor)

HOST = "192.168.88.120" # Use Your Arduino's IP. It will print when

#You Run the Arduino Server Program

PORT = 12345 # Must match Arduino’s UDP port

# Create a UDP socket

mySocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

mySocket.settimeout(5.0) # 5 seconds timeout for responses

Period = 5

frequency = 1/Period

numPoints = 500

timeStep = Period/numPoints

redData = [0]*numPoints

timeData =[0]*numPoints

app = QApplication([])

window = QMainWindow()

window.setWindowTitle("Red Sine Wave Graph")

window.setGeometry(100,100,800,600)

screens =QGuiApplication.screens()

window.move(screens[1].geometry().x() +100,screens[1].geometry().y() +100)

widgetContainer =QWidget()

window.setCentralWidget(widgetContainer)

mainLayout = QVBoxLayout(widgetContainer)

plotWidget = pg.PlotWidget()

plotWidget.setLabel("left", "y=sin(2*Pi*f*t")

plotWidget.setLabel("bottom", "Time (s)")

plotWidget.setTitle("My Fine Sin Wave")

plotWidget.addLegend()

mainLayout.addWidget(plotWidget)

for i in range(numPoints):

t = i * timeStep

timeData[i] = t

redData[i] = sin(2*pi*frequency*t)

redPlot = plotWidget.plot(timeData,redData, pen=pg.mkPen("r", width=3), name="Red")

tStart = time.perf_counter()

def updateGraph():

global t,tStart,frequency

t = t +timeStep

r= sin(2*pi*frequency*t)

redWrite = int((r*255 + 255)/2)

myData= str(redWrite)+'\n'

myDataEncoded=myData.encode()

mySocket.sendto(myDataEncoded, (HOST,PORT))

for i in range(numPoints -1):

redData[i] = redData[i+1]

timeData[i] = timeData[i+1]

redData[numPoints - 1] = r

timeData[numPoints -1] = t

redPlot.setData(timeData,redData)

if redData[0] <=0 and redData[1] > 0:

measuredPeriod = time.perf_counter() - tStart

print("Measured Period: ",measuredPeriod)

tStart = time.perf_counter()

timer = QTimer()

timer.timeout.connect(updateGraph)

timer.start(int(timeStep*1000))

window.show()

sys.exit(app.exec_())

Arduino, Python

Plot Live Data in Python Using PyQt5

June 18, 2025 admin

In this video lesson we show you how to plot live data in Python using PyQt5. In this lesson, we generate the data in python on the fly, but in future lessons we will bring the data in from the Arduino Project over WiFi using UDP. For your convenience, the code we developed in this lesson is below:

import pyqtgraph as pg
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
from PyQt5.QtGui import QGuiApplication
import sys
from math import sin,pi
import time

Period = 5
frequency = 1/Period
numPoints = 500
timeStep = Period/numPoints
redData = [0]*numPoints
timeData =[0]*numPoints

app = QApplication([])
window = QMainWindow()
window.setWindowTitle("Red Sine Wave Graph")
window.setGeometry(100,100,800,600)

#screens =QGuiApplication.screens()
#window.move(screens[1].geometry().x() +100,screens[1].geometry().y() +100)

widgetContainer =QWidget()
window.setCentralWidget(widgetContainer)

mainLayout = QVBoxLayout(widgetContainer)

plotWidget = pg.PlotWidget()
plotWidget.setLabel("left", "y=sin(2*Pi*f*t")
plotWidget.setLabel("bottom", "Time (s)")
plotWidget.setTitle("My Fine Sin Wave")
plotWidget.addLegend()
mainLayout.addWidget(plotWidget)

for i in range(numPoints):
    t = i * timeStep
    timeData[i] = t
    redData[i] = sin(2*pi*frequency*t)

redPlot = plotWidget.plot(timeData,redData, pen=pg.mkPen("r", width=3), name="Red")
tStart = time.perf_counter()
def updateGraph():
    global t,tStart,frequency
    t = t +timeStep
    r= sin(2*pi*frequency*t)
    for i in range(numPoints -1):
        redData[i] = redData[i+1]
        timeData[i] = timeData[i+1]
    redData[numPoints - 1] = r
    timeData[numPoints -1] = t
    redPlot.setData(timeData,redData)
    if redData[0] <=0 and redData[1] > 0:
        measuredPeriod = time.perf_counter() - tStart
        print("Measured Period: ",measuredPeriod)
        tStart = time.perf_counter()

timer = QTimer()
timer.timeout.connect(updateGraph)
timer.start(int(timeStep*1000))

window.show()
sys.exit(app.exec_())

import pyqtgraph as pg

from PyQt5.QtWidgets import *

from PyQt5.QtCore import *

from PyQt5.QtGui import QGuiApplication

import sys

from math import sin,pi

import time

Period = 5

frequency = 1/Period

numPoints = 500

timeStep = Period/numPoints

redData = [0]*numPoints

timeData =[0]*numPoints

app = QApplication([])

window = QMainWindow()

window.setWindowTitle("Red Sine Wave Graph")

window.setGeometry(100,100,800,600)

#screens =QGuiApplication.screens()

#window.move(screens[1].geometry().x() +100,screens[1].geometry().y() +100)

widgetContainer =QWidget()

window.setCentralWidget(widgetContainer)

mainLayout = QVBoxLayout(widgetContainer)

plotWidget = pg.PlotWidget()

plotWidget.setLabel("left", "y=sin(2*Pi*f*t")

plotWidget.setLabel("bottom", "Time (s)")

plotWidget.setTitle("My Fine Sin Wave")

plotWidget.addLegend()

mainLayout.addWidget(plotWidget)

for i in range(numPoints):

t = i * timeStep

timeData[i] = t

redData[i] = sin(2*pi*frequency*t)

redPlot = plotWidget.plot(timeData,redData, pen=pg.mkPen("r", width=3), name="Red")

tStart = time.perf_counter()

def updateGraph():

global t,tStart,frequency

t = t +timeStep

r= sin(2*pi*frequency*t)

for i in range(numPoints -1):

redData[i] = redData[i+1]

timeData[i] = timeData[i+1]

redData[numPoints - 1] = r

timeData[numPoints -1] = t

redPlot.setData(timeData,redData)

if redData[0] <=0 and redData[1] > 0:

measuredPeriod = time.perf_counter() - tStart

print("Measured Period: ",measuredPeriod)

tStart = time.perf_counter()

timer = QTimer()

timer.timeout.connect(updateGraph)

timer.start(int(timeStep*1000))

window.show()

sys.exit(app.exec_())

Arduino, Python

Use PyQt5 to Create a Graphical User Interface for Arduino Project Over WiFi

May 22, 2025 admin

In this video lesson we introduce you to creating Graphical User Interfaces (GUI) to control your arduino project over WiFi using PyQt5. For this first introduction, we show you how to create the PyQt5 Widget on your PC using Python. Then your homework will be to control your arduino using the widget over WiFi. For your convenience, the code we developed in the lesson is presented below.

from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
import sys

app = QApplication([])

window = QMainWindow()
window.setWindowTitle('Welcome to GUI World')
window.setGeometry(100,100,500,300)

widgetContainer = QWidget()
window.setCentralWidget(widgetContainer)
mainLayout = QVBoxLayout(widgetContainer)

label = QLabel("Welcome to PyQt5!")
label.setAlignment(Qt.AlignCenter)
label.setStyleSheet("font-size: 24px; color: blue; padding: 10px;")
label.setFixedHeight(50)
mainLayout.addWidget(label)

pushButtonLayout = QHBoxLayout()
mainLayout.addLayout(pushButtonLayout)

pushButtonRed = QPushButton("Blink Red!")
pushButtonRed.setStyleSheet("background-color: red; color: white; font-size: 24px; padding:10;")
pushButtonRed.setFixedSize(150,50)
def pushButtonRedClicked():
    label.setText("Blink Red!")
    label.setStyleSheet(" font-size: 24px;color: red; padding:10;")
pushButtonRed.clicked.connect(pushButtonRedClicked)
pushButtonLayout.addWidget(pushButtonRed)

pushButtonGreen = QPushButton("Blink Green!")
pushButtonGreen.setStyleSheet("background-color: green; color: white; font-size: 24px; padding:10;")
pushButtonGreen.setFixedSize(150,50)
def pushButtonGreenClicked():
    label.setText("Blink Green!")
    label.setStyleSheet(" font-size: 24px;color: green; padding:10;")
pushButtonGreen.clicked.connect(pushButtonGreenClicked)
pushButtonLayout.addWidget(pushButtonGreen)

pushButtonBlue = QPushButton("Blink Blue!")
pushButtonBlue.setStyleSheet("background-color: blue; color: white; font-size: 24px; padding:10;")
pushButtonBlue.setFixedSize(150,50)
def pushButtonBlueClicked():
    label.setText("Blink Blue!")
    label.setStyleSheet(" font-size: 24px;color: blue; padding:10;")
pushButtonBlue.clicked.connect(pushButtonBlueClicked)
pushButtonLayout.addWidget(pushButtonBlue)

toggleButtonLayout = QHBoxLayout()
mainLayout.addLayout(toggleButtonLayout)


toggleButtonRed = QPushButton("Toggle Red")
toggleButtonRed.setCheckable(True)
toggleButtonRed.setStyleSheet("background-color: red; color: white; font-size: 18px; padding:10;")
toggleButtonRed.setFixedSize(150,50)
def toggleRed(checked):
    if checked:
        label.setText("Red Toggle ON")
        label.setStyleSheet(" font-size: 24px;color: red; padding:10;")
        
    if not checked:
        label.setText("Red Toggle OFF")
        label.setStyleSheet(" font-size: 24px;color: red; padding:10;")

toggleButtonRed.toggled.connect(toggleRed)
toggleButtonLayout.addWidget(toggleButtonRed)

toggleButtonGreen = QPushButton("Toggle Green")
toggleButtonGreen.setCheckable(True)
toggleButtonGreen.setStyleSheet("background-color: green; color: white; font-size: 18px; padding:10;")
toggleButtonGreen.setFixedSize(150,50)
def toggleGreen(checked):
    if checked:
        label.setText("Green Toggle ON")
        label.setStyleSheet(" font-size: 24px;color: green; padding:10;")
        
    if not checked:
        label.setText("Green Toggle OFF")
        label.setStyleSheet(" font-size: 24px;color: green; padding:10;")

toggleButtonGreen.toggled.connect(toggleGreen)
toggleButtonLayout.addWidget(toggleButtonGreen)

toggleButtonBlue = QPushButton("Toggle Blue")
toggleButtonBlue.setCheckable(True)
toggleButtonBlue.setStyleSheet("background-color: blue; color: white; font-size: 18px; padding:10;")
toggleButtonBlue.setFixedSize(150,50)
def toggleBlue(checked):
    if checked:
        label.setText("Blue Toggle ON")
        label.setStyleSheet(" font-size: 24px;color: blue; padding:10;")
        
    if not checked:
        label.setText("Blue Toggle OFF")
        label.setStyleSheet(" font-size: 24px;color: bllue; padding:10;")

toggleButtonBlue.toggled.connect(toggleBlue)
toggleButtonLayout.addWidget(toggleButtonBlue)

mainLayout.addStretch()
window.show()
sys.exit(app.exec_())

100

101

102

103

104

105

from PyQt5.QtWidgets import *

from PyQt5.QtCore import *

import sys

app = QApplication([])

window = QMainWindow()

window.setWindowTitle('Welcome to GUI World')

window.setGeometry(100,100,500,300)

widgetContainer = QWidget()

window.setCentralWidget(widgetContainer)

mainLayout = QVBoxLayout(widgetContainer)

label = QLabel("Welcome to PyQt5!")

label.setAlignment(Qt.AlignCenter)

label.setStyleSheet("font-size: 24px; color: blue; padding: 10px;")

label.setFixedHeight(50)

mainLayout.addWidget(label)

pushButtonLayout = QHBoxLayout()

mainLayout.addLayout(pushButtonLayout)

pushButtonRed = QPushButton("Blink Red!")

pushButtonRed.setStyleSheet("background-color: red; color: white; font-size: 24px; padding:10;")

pushButtonRed.setFixedSize(150,50)

def pushButtonRedClicked():

label.setText("Blink Red!")

label.setStyleSheet(" font-size: 24px;color: red; padding:10;")

pushButtonRed.clicked.connect(pushButtonRedClicked)

pushButtonLayout.addWidget(pushButtonRed)

pushButtonGreen = QPushButton("Blink Green!")

pushButtonGreen.setStyleSheet("background-color: green; color: white; font-size: 24px; padding:10;")

pushButtonGreen.setFixedSize(150,50)

def pushButtonGreenClicked():

label.setText("Blink Green!")

label.setStyleSheet(" font-size: 24px;color: green; padding:10;")

pushButtonGreen.clicked.connect(pushButtonGreenClicked)

pushButtonLayout.addWidget(pushButtonGreen)

pushButtonBlue = QPushButton("Blink Blue!")

pushButtonBlue.setStyleSheet("background-color: blue; color: white; font-size: 24px; padding:10;")

pushButtonBlue.setFixedSize(150,50)

def pushButtonBlueClicked():

label.setText("Blink Blue!")

label.setStyleSheet(" font-size: 24px;color: blue; padding:10;")

pushButtonBlue.clicked.connect(pushButtonBlueClicked)

pushButtonLayout.addWidget(pushButtonBlue)

toggleButtonLayout = QHBoxLayout()

mainLayout.addLayout(toggleButtonLayout)

toggleButtonRed = QPushButton("Toggle Red")

toggleButtonRed.setCheckable(True)

toggleButtonRed.setStyleSheet("background-color: red; color: white; font-size: 18px; padding:10;")

toggleButtonRed.setFixedSize(150,50)

def toggleRed(checked):

if checked:

label.setText("Red Toggle ON")

label.setStyleSheet(" font-size: 24px;color: red; padding:10;")

if not checked:

label.setText("Red Toggle OFF")

label.setStyleSheet(" font-size: 24px;color: red; padding:10;")

toggleButtonRed.toggled.connect(toggleRed)

toggleButtonLayout.addWidget(toggleButtonRed)

toggleButtonGreen = QPushButton("Toggle Green")

toggleButtonGreen.setCheckable(True)

toggleButtonGreen.setStyleSheet("background-color: green; color: white; font-size: 18px; padding:10;")

toggleButtonGreen.setFixedSize(150,50)

def toggleGreen(checked):

if checked:

label.setText("Green Toggle ON")

label.setStyleSheet(" font-size: 24px;color: green; padding:10;")

if not checked:

label.setText("Green Toggle OFF")

label.setStyleSheet(" font-size: 24px;color: green; padding:10;")

toggleButtonGreen.toggled.connect(toggleGreen)

toggleButtonLayout.addWidget(toggleButtonGreen)

toggleButtonBlue = QPushButton("Toggle Blue")

toggleButtonBlue.setCheckable(True)

toggleButtonBlue.setStyleSheet("background-color: blue; color: white; font-size: 18px; padding:10;")

toggleButtonBlue.setFixedSize(150,50)

def toggleBlue(checked):

if checked:

label.setText("Blue Toggle ON")

label.setStyleSheet(" font-size: 24px;color: blue; padding:10;")

if not checked:

label.setText("Blue Toggle OFF")

label.setStyleSheet(" font-size: 24px;color: bllue; padding:10;")

toggleButtonBlue.toggled.connect(toggleBlue)

toggleButtonLayout.addWidget(toggleButtonBlue)

mainLayout.addStretch()

window.show()

sys.exit(app.exec_())

Arduino, Arduino with Python, Python

Improved Client Server Framework for Arduino

May 16, 2025 admin

In this lesson, we show an improved framework for creating a Client/Server connection between your Arduino and your desktop PC over WiFi. This will serve as the basis for our WiFi projects moving forward. On the arduino side, we have the following code to create the Server:

#include <WiFiS3.h>
#include "secrets.h"
WiFiUDP udp;
int PORT = 12345;
String myString;
String stringArray[10];
String response = "ACK";
void setup() {
  Serial.begin(9600);
  Serial.print("Connecting to ");
  Serial.println(mySSID);
  WiFi.begin(mySSID, myPASS);
  while (WiFi.status() != WL_CONNECTED) {
    delay(100);
    Serial.print(".");
  }
  Serial.println("\nConnected to WiFi");
  Serial.println(WiFi.localIP());
  udp.begin(PORT);
  Serial.print("UDP Server started on port ");
  Serial.print(PORT);
  // put your setup code here, to run once:
}
void splitString() {
  int startIndex = 0;
  int indexCount = 0;
  int i;
  int j;
  myString = myString + ':';
  for (i = 0; i < myString.length(); i = i + 1) {
    if (myString[i] == ':') {
      stringArray[indexCount] = myString.substring(startIndex, i);
      indexCount = indexCount + 1;
      startIndex = i + 1;
    }
  }
  for (j = 0; j < indexCount; j = j + 1) {
    Serial.println(stringArray[j]);
  }
}

void loop() {
  // put your main code here, to run repeatedly:
  if (udp.parsePacket()) {
    myString = udp.readStringUntil('\n');
    Serial.println("Received : " + myString);
    udp.beginPacket(udp.remoteIP(), udp.remotePort());
    udp.print(response);
    udp.endPacket();
    Serial.println("SENT: " + response);
    splitString();
  }
}

#include <WiFiS3.h>

#include "secrets.h"

WiFiUDP udp;

int PORT = 12345;

String myString;

String stringArray[10];

String response = "ACK";

void setup() {

Serial.begin(9600);

Serial.print("Connecting to ");

Serial.println(mySSID);

WiFi.begin(mySSID, myPASS);

while (WiFi.status() != WL_CONNECTED) {

delay(100);

Serial.print(".");

}

Serial.println("\nConnected to WiFi");

Serial.println(WiFi.localIP());

udp.begin(PORT);

Serial.print("UDP Server started on port ");

Serial.print(PORT);

// put your setup code here, to run once:

}

void splitString() {

int startIndex = 0;

int indexCount = 0;

int i;

int j;

myString = myString + ':';

for (i = 0; i < myString.length(); i = i + 1) {

if (myString[i] == ':') {

stringArray[indexCount] = myString.substring(startIndex, i);

indexCount = indexCount + 1;

startIndex = i + 1;

}

for (j = 0; j < indexCount; j = j + 1) {

Serial.println(stringArray[j]);

}

void loop() {

// put your main code here, to run repeatedly:

if (udp.parsePacket()) {

myString = udp.readStringUntil('\n');

Serial.println("Received : " + myString);

udp.beginPacket(udp.remoteIP(), udp.remotePort());

udp.print(response);

udp.endPacket();

Serial.println("SENT: " + response);

splitString();

}

Remember, you must create a new tab, and include the following as your ‘secrets.h’ file

#define mySSID "YOUR WIFI NAME"
#define myPASS "YOUR WIFI PASSWORD"

1 2	#define mySSID "YOUR WIFI NAME" #define myPASS "YOUR WIFI PASSWORD"

And then, on the Desktop side, this will be your python ‘Client’ code:

import socket

# Arduino’s IP address (from Arduino Serial Monitor)
HOST = "192.168.88.33"  # Use Your Arduino's IP. It will print when
                        #You Run the Arduino Server Program
PORT = 12345            # Must match Arduino’s UDP port

# Create a UDP socket
mySocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
mySocket.settimeout(5.0)  # 5 seconds timeout for responses

print("UDP Client started. Enter Data (or 'quit' to exit).")

while True:
    # Prompt for Data
    myData = input("Enter Data String: ") 
    if myData.lower() == 'quit':  # Exit condition
        break
    # Send Data to the server
    myData=myData+'\n'
    myDataEncoded=myData.encode()
    mySocket.sendto(myDataEncoded, (HOST, PORT))
    print('Sent '+myData+' to HOST',HOST,PORT)

    # Try to get a response, skip on timeout
    try:
        response, server_address = mySocket.recvfrom(1024)
        print("Server response:", response.decode())
    except socket.timeout:
        print("No response received from server within 5 seconds")

# Close the socket
mySocket.close()
print("Socket closed")

import socket

# Arduino’s IP address (from Arduino Serial Monitor)

HOST = "192.168.88.33" # Use Your Arduino's IP. It will print when

#You Run the Arduino Server Program

PORT = 12345 # Must match Arduino’s UDP port

# Create a UDP socket

mySocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

mySocket.settimeout(5.0) # 5 seconds timeout for responses

print("UDP Client started. Enter Data (or 'quit' to exit).")

while True:

# Prompt for Data

myData = input("Enter Data String: ")

if myData.lower() == 'quit': # Exit condition

break

# Send Data to the server

myData=myData+'\n'

myDataEncoded=myData.encode()

mySocket.sendto(myDataEncoded, (HOST, PORT))

print('Sent '+myData+' to HOST',HOST,PORT)

# Try to get a response, skip on timeout

try:

response, server_address = mySocket.recvfrom(1024)

print("Server response:", response.decode())

except socket.timeout:

print("No response received from server within 5 seconds")

# Close the socket

mySocket.close()

print("Socket closed")

Arduino, Python

Parsing Comma Delimited Data Strings in Arduino

May 1, 2025 admin

In this lesson we are working on a client server connection. The Arduino is the server, and a python program on a desktop PC is the client. The objective is to control the color of an RGB LED from the client. The client will send data to the server as comma delimited string, like 255,0,255 for RGB. The challenge on the server side is to parse this data so we get integer values of:

R=255

G=0

B=255

In this video lesson we start by simply controlling two LED, a red and green one, from the python client. We then show how we can control an RGB LED by sending the data string from the client, and parsing it on the server side. For your convenience, we include the code here:

Server Side code for the Arduino:

#include <WiFiS3.h>
#include "secrets.h"
WiFiUDP udp;
int PORT = 12345;
char myPacket[255];
int dataLen;
String color;
String response;
int redPin = 8;
int greenPin = 9;
int R;
int G;
int B;
int firstComma;
int secondComma;
void setup() {
  Serial.begin(9600);
  pinMode(redPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
  Serial.print("Connecting to ");
  Serial.println(SSID);
  WiFi.begin(SSID, PASS);
  while (WiFi.status() != WL_CONNECTED) {
    delay(100);
    Serial.print(".");
  }
  Serial.println("\nConnected to WiFi");
  Serial.println(WiFi.localIP());
  udp.begin(PORT);
  Serial.print("UDP Server started on port ");
  Serial.print(PORT);
  // put your setup code here, to run once:
}

void loop() {
  // put your main code here, to run repeatedly:
  if (udp.parsePacket()) {
    dataLen = udp.available();
    Serial.println(dataLen);
    udp.read(myPacket, 255);
    Serial.println(myPacket);
    myPacket[dataLen] = 0;
    Serial.println(myPacket);
    color = String(myPacket);
    color.trim();
    Serial.println("Received color: " + color);
    firstComma=color.indexOf(',',0);
    secondComma=color.indexOf(',',firstComma+1);
    R=color.substring(0,firstComma).toInt();
    G=color.substring(firstComma+1,secondComma).toInt();
    B=color.substring(secondComma+1).toInt();
    Serial.println(R);
    Serial.println(G);
    Serial.println(B);
    udp.beginPacket(udp.remoteIP(), udp.remotePort());
    udp.print(response);
    udp.endPacket();
    Serial.println("SENT: " + response);
  }
}

#include <WiFiS3.h>

#include "secrets.h"

WiFiUDP udp;

int PORT = 12345;

char myPacket[255];

int dataLen;

String color;

String response;

int redPin = 8;

int greenPin = 9;

int R;

int G;

int B;

int firstComma;

int secondComma;

void setup() {

Serial.begin(9600);

pinMode(redPin, OUTPUT);

pinMode(greenPin, OUTPUT);

Serial.print("Connecting to ");

Serial.println(SSID);

WiFi.begin(SSID, PASS);

while (WiFi.status() != WL_CONNECTED) {

delay(100);

Serial.print(".");

}

Serial.println("\nConnected to WiFi");

Serial.println(WiFi.localIP());

udp.begin(PORT);

Serial.print("UDP Server started on port ");

Serial.print(PORT);

// put your setup code here, to run once:

}

void loop() {

// put your main code here, to run repeatedly:

if (udp.parsePacket()) {

dataLen = udp.available();

Serial.println(dataLen);

udp.read(myPacket, 255);

Serial.println(myPacket);

myPacket[dataLen] = 0;

Serial.println(myPacket);

color = String(myPacket);

color.trim();

Serial.println("Received color: " + color);

firstComma=color.indexOf(',',0);

secondComma=color.indexOf(',',firstComma+1);

R=color.substring(0,firstComma).toInt();

G=color.substring(firstComma+1,secondComma).toInt();

B=color.substring(secondComma+1).toInt();

Serial.println(R);

Serial.println(G);

Serial.println(B);

udp.beginPacket(udp.remoteIP(), udp.remotePort());

udp.print(response);

udp.endPacket();

Serial.println("SENT: " + response);

}

The code above needs a ‘secrets.h’ file which includes your WiFi name and password. This is created in the IDE by choosing ‘Add Tab’. Call the new tab ‘secrets.h’, and edit the code below to include your WiFi name and passwords inside the quotes:

#define SSID "Your WiFi Name"
#define PASS "Your WiFi Password"

1 2	#define SSID "Your WiFi Name" #define PASS "Your WiFi Password"

Now, on the client side, this is our standard Python client:

import socket

# Arduino’s IP address (from Arduino Serial Monitor)
HOST = "192.168.88.77"  # Use Your Arduino's IP. It will print when
                        #You Run the Arduino Server Program
PORT = 12345            # Must match Arduino’s UDP port

# Create a UDP socket
mySocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
mySocket.settimeout(5.0)  # 5 seconds timeout for responses

print("UDP Client started. Enter a color (or 'quit' to exit).")

while True:
    # Prompt for a color
    #color = input("Enter a color: ").strip()  # Remove whitespace
    color = input("Enter a color: ") 
    if color.lower() == 'quit':  # Exit condition
        break

    # Send the color to the server
    sendColor=color.encode()
    mySocket.sendto(sendColor, (HOST, PORT))
    print('Sent '+color+' to HOST',HOST,PORT)

    # Try to get a response, skip on timeout
    try:
        response, server_address = mySocket.recvfrom(1024)
        print("Server response:", response.decode())
    except socket.timeout:
        print("No response received from server within 5 seconds")

# Close the socket
mySocket.close()
print("Socket closed")

import socket

# Arduino’s IP address (from Arduino Serial Monitor)

HOST = "192.168.88.77" # Use Your Arduino's IP. It will print when

#You Run the Arduino Server Program

PORT = 12345 # Must match Arduino’s UDP port

# Create a UDP socket

mySocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

mySocket.settimeout(5.0) # 5 seconds timeout for responses

print("UDP Client started. Enter a color (or 'quit' to exit).")

while True:

# Prompt for a color

#color = input("Enter a color: ").strip() # Remove whitespace

color = input("Enter a color: ")

if color.lower() == 'quit': # Exit condition

break

# Send the color to the server

sendColor=color.encode()

mySocket.sendto(sendColor, (HOST, PORT))

print('Sent '+color+' to HOST',HOST,PORT)

# Try to get a response, skip on timeout

try:

response, server_address = mySocket.recvfrom(1024)

print("Server response:", response.decode())

except socket.timeout:

print("No response received from server within 5 seconds")

# Close the socket

mySocket.close()

print("Socket closed")

With this code for creating a client and server, and then parsing comma delimited text, you can easily add the code needed to control the RGB LED color to the arduino program.

Technology Tutorials

Category Archives: Python

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Use PyQt5 to Create a Graphical User Interface for Arduino Project Over WiFi

Improved Client Server Framework for Arduino

Parsing Comma Delimited Data Strings in Arduino

Making The World a Better Place One High Tech Project at a Time. Enjoy!