Tag Archives: Client Server

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:

// ====================================================================
// DISCLAIMER:
// This code is provided as-is for educational and experimental 
// purposes only. The author makes no representations or warranties of 
// any kind concerning the safety, suitability, or accuracy of this 
// code. Use at your own risk. The author assumes no liability for any 
// damages, system failures, security breaches, or network issues 
// resulting from the use or implementation of this script.
// ====================================================================

#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();
  }
}

// ====================================================================

// DISCLAIMER:

// This code is provided as-is for educational and experimental

// purposes only. The author makes no representations or warranties of

// any kind concerning the safety, suitability, or accuracy of this

// code. Use at your own risk. The author assumes no liability for any

// damages, system failures, security breaches, or network issues

// resulting from the use or implementation of this script.

// ====================================================================

#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:

# ====================================================================
# DISCLAIMER:
# This code is provided as-is for educational and experimental 
# purposes only. The author makes no representations or warranties of 
# any kind concerning the safety, suitability, or accuracy of this 
# code. Use at your own risk. The author assumes no liability for any 
# damages, system failures, security breaches, or network issues 
# resulting from the use or implementation of this script.
# ====================================================================

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")

# ====================================================================

# DISCLAIMER:

# This code is provided as-is for educational and experimental

# purposes only. The author makes no representations or warranties of

# any kind concerning the safety, suitability, or accuracy of this

# code. Use at your own risk. The author assumes no liability for any

# damages, system failures, security breaches, or network issues

# resulting from the use or implementation of this script.

# ====================================================================

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")

Python, Raspberry Pi Pico

Simple Client Server Project for the Raspberry Pi Pico W

February 25, 2025 admin

In this video lesson we demonstrate a simple client server project on the Raspberry Pi Pico W. The Pico is configures as the server, and your desktop pc or laptop is configures to be the client. You will be running python on your PC. The project requests the user on the PC to specify a desired color. The color is then sent to the Pico, the Server.

For this lesson we are not using the breadvolt power supply, but we will use it in future lessons. For this lesson, you do not need to attach it, and if you do attach it, leave it ‘off’.

Below is the schematic for the Server Side of the project:

LED and Buttons — Schematic for Circuit to Demonstrate a Client Server Example on Pi Pico

For your convenience, this is the code we developed in the video

# ====================================================================
# DISCLAIMER:
# This code is provided as-is for educational and experimental 
# purposes only. The author makes no representations or warranties of 
# any kind concerning the safety, suitability, or accuracy of this 
# code. Use at your own risk. The author assumes no liability for any 
# damages, system failures, security breaches, or network issues 
# resulting from the use or implementation of this script.
# ====================================================================

import network
import usocket as socket
import secrets
import time

greenLED=machine.Pin(18,machine.Pin.OUT)
yellowLED=machine.Pin(19,machine.Pin.OUT)
redLED=machine.Pin(20,machine.Pin.OUT)
# Set up WiFi connection
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
print(secrets.SSID,secrets.PASSWORD)
wlan.connect(secrets.SSID,secrets.PASSWORD)

# Wait for connection
ts=1
while not wlan.isconnected():
    time.sleep(ts)
print("Connection Completed")
print('WiFi connected')
print(wlan.ifconfig())

# Set up UDP server
server_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
server_socket.bind((wlan.ifconfig()[0], 12345))
print("Server is Up and Listening")
print(wlan.ifconfig()[0])

while True:
    print('Waiting for a request from the client...')
    # Receive request from client
    color, client_address = server_socket.recvfrom(1024)
    color=color.decode()
    print("Client Request:",color)
    print("FROM CLIENT",client_address)
    
    if (color=="green"):
        greenLED.on()
        yellowLED.off()
        redLED.off()
    if (color=="yellow"):
        greenLED.off()
        yellowLED.on()
        redLED.off()
    if (color=="red"):
        greenLED.off()
        yellowLED.off()
        redLED.on()
    if (color=="off"):
        greenLED.off()
        yellowLED.off()
        redLED.off()
    
    # Send data to client
    data="LED "+color+" executed"
    server_socket.sendto(data.encode(), client_address)
    print(f'Sent data to {client_address}')
    
    # Optional: Pause for a short period to prevent overwhelming the client
    time.sleep(ts)

# ====================================================================

# DISCLAIMER:

# This code is provided as-is for educational and experimental

# purposes only. The author makes no representations or warranties of

# any kind concerning the safety, suitability, or accuracy of this

# code. Use at your own risk. The author assumes no liability for any

# damages, system failures, security breaches, or network issues

# resulting from the use or implementation of this script.

# ====================================================================

import network

import usocket as socket

import secrets

import time

greenLED=machine.Pin(18,machine.Pin.OUT)

yellowLED=machine.Pin(19,machine.Pin.OUT)

redLED=machine.Pin(20,machine.Pin.OUT)

# Set up WiFi connection

wlan = network.WLAN(network.STA_IF)

wlan.active(True)

print(secrets.SSID,secrets.PASSWORD)

wlan.connect(secrets.SSID,secrets.PASSWORD)

# Wait for connection

ts=1

while not wlan.isconnected():

time.sleep(ts)

print("Connection Completed")

print('WiFi connected')

print(wlan.ifconfig())

# Set up UDP server

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

server_socket.bind((wlan.ifconfig()[0], 12345))

print("Server is Up and Listening")

print(wlan.ifconfig()[0])

while True:

print('Waiting for a request from the client...')

# Receive request from client

color, client_address = server_socket.recvfrom(1024)

color=color.decode()

print("Client Request:",color)

print("FROM CLIENT",client_address)

if (color=="green"):

greenLED.on()

yellowLED.off()

redLED.off()

if (color=="yellow"):

greenLED.off()

yellowLED.on()

redLED.off()

if (color=="red"):

greenLED.off()

yellowLED.off()

redLED.on()

if (color=="off"):

greenLED.off()

yellowLED.off()

redLED.off()

# Send data to client

data="LED "+color+" executed"

server_socket.sendto(data.encode(), client_address)

print(f'Sent data to {client_address}')

# Optional: Pause for a short period to prevent overwhelming the client

time.sleep(ts)

Remember you must create a secrets.py file, and save it on the Pi Pico in the lib folder. You need to specify YOUR WiFi name and password in the file.

SSID="YOUR WIFI NAME"
PASSWORD="YOUR WIFI PASSWORD"

1 2	SSID="YOUR WIFI NAME" PASSWORD="YOUR WIFI PASSWORD"

And finally, here is the code to run on the client side on your PC

# ====================================================================
# DISCLAIMER:
# This code is provided as-is for educational and experimental 
# purposes only. The author makes no representations or warranties of 
# any kind concerning the safety, suitability, or accuracy of this 
# code. Use at your own risk. The author assumes no liability for any 
# damages, system failures, security breaches, or network issues 
# resulting from the use or implementation of this script.
# ====================================================================

import socket
import time

# Set up UDP client
client_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
server_address = ('192.168.88.71', 12345)  # Adjust IP address and port as needed

while True:
    # Send request to the server
    myColor=input("Please Input Your Color (Green, Yellow, Red, Off )")
    myColor=myColor.lower()
    client_socket.sendto(myColor.encode(), server_address)
    
    # Receive data from the server
    data, addr = client_socket.recvfrom(1024)
    print('Received data:', data.decode())

# ====================================================================

# DISCLAIMER:

# This code is provided as-is for educational and experimental

# purposes only. The author makes no representations or warranties of

# any kind concerning the safety, suitability, or accuracy of this

# code. Use at your own risk. The author assumes no liability for any

# damages, system failures, security breaches, or network issues

# resulting from the use or implementation of this script.

# ====================================================================

import socket

import time

# Set up UDP client

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

server_address = ('192.168.88.71', 12345) # Adjust IP address and port as needed

while True:

# Send request to the server

myColor=input("Please Input Your Color (Green, Yellow, Red, Off )")

myColor=myColor.lower()

client_socket.sendto(myColor.encode(), server_address)

# Receive data from the server

data, addr = client_socket.recvfrom(1024)

print('Received data:', data.decode())

Technology Tutorials

Tag Archives: Client Server

Improved Client Server Framework for Arduino

Simple Client Server Project for the Raspberry Pi Pico W

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