Tag Archives: Server

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

Create a Simple Client Server Connection Over WiFi to Connect Arduino to Python on the PC

April 24, 2025 admin

In this video lesson, we show how to create a simple Client/Server connection over WiFi. We connect the Arduino Uno R4 WiFi to Python running on the PC. The arduino is the server, and the PC Python program is the client. We show how to pass data from the PC to the Arduino, and then how to pass data from the Arduino back to the PC. With this simple framework, we can control Arduino projects from our desktop PC, and we can use the PC to display data being taken from the Arduino.

In this lesson we develop code for Arduino, and the code in Python. For your convenience, we present the code below.

On the Arduino Side, this is the code to create the ‘Server’.

#include <WiFiS3.h>
#include "secrets.h"
WiFiUDP udp;
int PORT = 12345;
char myPacket[255];
int dataLen;
String color;
String response;
void setup() {
  Serial.begin(9600);
  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);
  response ="Here is your "+color+" Marble";  
 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;

void setup() {

Serial.begin(9600);

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);

response ="Here is your "+color+" Marble";

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

udp.print(response);

udp.endPacket();

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

}

You also need to add a tab to your program using the ‘Add Tab’ feature of the IDE. The program in the tab should be named secrets.h

Your secrets.h file should look like this:

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

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

You can run the program above, and it should connect to your WiFi, and should print out the Arduino’s IP address. Make note of the IP address as it will be needed in the Client program below. On the PC side, this is the python code to create the 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")

Arduino with Python, Tutorial

Python with Arduino LESSON 16: Simple Client Server Configuration over Ethernet

April 3, 2015 admin

Arduino and Ethernet Shield — Ethernet Shields are available which allow the arduino to act as a server

In the previous lessons we have seen that powerful analytic and graphic programs can be written that allow data taken from the arduino to be displayed on a PC via Python. We have shown how the arduino can be connected to a PC by either a serial cable or Xbee radios. To fully unleash the power of the arduino, it can be set up as a server, and connected to a network via Ethernet. In this lesson, we will show how to set the arduino up as a server which is controlled and queried by clients on PC’s on the same network. In order to complete this tutorial, you will need an Arduino Uno and an Ethernet shield. The Ethernet Shield is a relatively expensive component, but I suggest getting an authentic arduino made shield, as I have had poor results from the cheap knock offs. Understand that this lesson is intended for High School students to show them a simple technique for connecting the arduino to a network. It is not an exhaustive treatise on Ethernet communication. The goal is to provide a simple protocol which should allow you to get your arduino talking over Ethernet. It requires that you already know, or can figure out how to assign a mac address and IP address in your router. Some arduino Ethernet shields have a sticker with a mac address. If your Ethernet shield has a sticker with mac address, use that one. If it does not, you will need to come up with a unique mac address. If you are at school, the network administrator can help you get the router configured. I can not provide support in getting this to work on your network, as there are many variables. The techniques provided in this tutorial should work for most networks. This tutorial does not present the most efficient or elegant solution, but the goal is a simple protocol for people just getting started. The video below gives a step-by-step demonstration of setting up the arduino as a server, and Python on a PC as the client. It uses UDP protocol to transfer data packets.

In order to get the arduino to work over Ethernet, you must first assign an IP address to the arduino in your router. If you just plug the arduino with shield into the network, your router might assign an IP and report a mac address. If this is the case, you need to have the router assign those addresses permanently to the arduino. The bottom line is that the IP address and mac address you identify in the arduino code must match the IP address and mac address assigned in the router. I can not provide any additional help on that issue as there are so many different possible networks. You have to figure out how to do that.

Once you have the IP address and mac address sorted out, you will need to set up the arduino as a server. The video above explains how to do this, and results in this code. Note that your IP address and mac address must be set to a suitable configuration for your router and network. The numbers I use in this code would not work for your network.

This is the code developed in the video to set the arduino up:

#include <Ethernet.h> //Load Ethernet Library
#include <EthernetUdp.h> //Load UDP Library
#include <SPI.h> //Load the SPI Library

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xEE}; //Assign a mac address
IPAddress ip(10, 1, 15, 243); //Assign my IP adress
unsigned int localPort = 5000; //Assign a Port to talk over
char packetBuffer[UDP_TX_PACKET_MAX_SIZE];
String datReq; //String for our data
int packetSize; //Size of Packet
EthernetUDP Udp; //Define UDP Object

void setup() {
  
Serial.begin(9600); //Turn on Serial Port
Ethernet.begin(mac, ip); //Initialize Ethernet
Udp.begin(localPort); //Initialize Udp
delay(1500); //delay
}

void loop() {
  
  packetSize = Udp.parsePacket(); //Read theh packetSize
  
  if(packetSize>0){ //Check to see if a request is present
  
  Udp.read(packetBuffer, UDP_TX_PACKET_MAX_SIZE); //Reading the data request on the Udp
  String datReq(packetBuffer); //Convert packetBuffer array to string datReq
  
  if (datReq =="Red") { //See if Red was requested
  
    Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());  //Initialize Packet send
    Udp.print("You are Asking for Red"); //Send string back to client 
    Udp.endPacket(); //Packet has been sent
  }
   if (datReq =="Green") { //See if Green was requested
  
    Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());  //Initialize Packet send
    Udp.print("You are Asking for Green"); //Send string back to client 
    Udp.endPacket(); //Packet has been sent
   }
    if (datReq =="Blue") { //See if Red was requested
  
    Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());  //Initialize Packet send
    Udp.print("You are Asking for Blue"); //Send string back to client 
    Udp.endPacket(); //Packet has been sent
    }
  }
  memset(packetBuffer, 0, UDP_TX_PACKET_MAX_SIZE);
}

#include <Ethernet.h> //Load Ethernet Library

#include <EthernetUdp.h> //Load UDP Library

#include <SPI.h> //Load the SPI Library

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xEE}; //Assign a mac address

IPAddress ip(10, 1, 15, 243); //Assign my IP adress

unsigned int localPort = 5000; //Assign a Port to talk over

char packetBuffer[UDP_TX_PACKET_MAX_SIZE];

String datReq; //String for our data

int packetSize; //Size of Packet

EthernetUDP Udp; //Define UDP Object

void setup() {

Serial.begin(9600); //Turn on Serial Port

Ethernet.begin(mac, ip); //Initialize Ethernet

Udp.begin(localPort); //Initialize Udp

delay(1500); //delay

}

void loop() {

packetSize = Udp.parsePacket(); //Read theh packetSize

if(packetSize>0){ //Check to see if a request is present

Udp.read(packetBuffer, UDP_TX_PACKET_MAX_SIZE); //Reading the data request on the Udp

String datReq(packetBuffer); //Convert packetBuffer array to string datReq

if (datReq =="Red") { //See if Red was requested

Udp.beginPacket(Udp.remoteIP(), Udp.remotePort()); //Initialize Packet send

Udp.print("You are Asking for Red"); //Send string back to client

Udp.endPacket(); //Packet has been sent

}

if (datReq =="Green") { //See if Green was requested

Udp.beginPacket(Udp.remoteIP(), Udp.remotePort()); //Initialize Packet send

Udp.print("You are Asking for Green"); //Send string back to client

Udp.endPacket(); //Packet has been sent

}

if (datReq =="Blue") { //See if Red was requested

Udp.beginPacket(Udp.remoteIP(), Udp.remotePort()); //Initialize Packet send

Udp.print("You are Asking for Blue"); //Send string back to client

Udp.endPacket(); //Packet has been sent

}

memset(packetBuffer, 0, UDP_TX_PACKET_MAX_SIZE);

}

Once you have this code in your arduino, ping the IP address of the arduino from your PC cmd line. Make sure your PC can talk to the arduino by successfully pinging it. If you get an error while you are trying to ping the arduino, you will have to stop and get figured out what is wrong. There is no reason to proceed with the lesson until you can successfully ping the arduino.

Once you can ping the arduino, you are ready to set up a client in Python. The code below is what we developed in the video. You will need to watch the video in order to understand the code. Also note, that the IP address in the code below is the IP address of the Arduino, NOT the PC. You should set this to whatever IP address is of YOUR arduino.

from socket import *
import time

address = ( '10.1.15.243', 5000) #Defind who you are talking to (must match arduino IP and port)
client_socket = socket(AF_INET, SOCK_DGRAM) #Set Up the Socket
client_socket.settimeout(1) #only wait 1 second for a resonse

while(1): #Main Loop

    data = "Blue" #Set data to Blue Command
    client_socket.sendto(data, address) #send command to arduino
    try:
        rec_data, addr = client_socket.recvfrom(2048) #Read response from arduino
        print rec_data #Print the response from Arduino
    except:
        pass

    time.sleep(2) #delay before sending next command

    data = "Red" #Set data to Blue Command
    client_socket.sendto(data, address) #send command to arduino
    try:
        rec_data, addr = client_socket.recvfrom(2048) #Read response from arduino
        print rec_data #Print the response from Arduino
    except:
        pass

    time.sleep(2) #delay before sending next command
    
    data = "Green" #Set data to Blue Command
    client_socket.sendto(data, address) #send command to arduino
    try:
        rec_data, addr = client_socket.recvfrom(2048) #Read response from arduino
        print rec_data #Print the response from Arduino
    except:
        pass
    time.sleep(2) #delay before sending next command

from socket import *

import time

address = ( '10.1.15.243', 5000) #Defind who you are talking to (must match arduino IP and port)

client_socket = socket(AF_INET, SOCK_DGRAM) #Set Up the Socket

client_socket.settimeout(1) #only wait 1 second for a resonse

while(1): #Main Loop

data = "Blue" #Set data to Blue Command

client_socket.sendto(data, address) #send command to arduino

try:

rec_data, addr = client_socket.recvfrom(2048) #Read response from arduino

print rec_data #Print the response from Arduino

except:

pass

time.sleep(2) #delay before sending next command

data = "Red" #Set data to Blue Command

client_socket.sendto(data, address) #send command to arduino

try:

rec_data, addr = client_socket.recvfrom(2048) #Read response from arduino

print rec_data #Print the response from Arduino

except:

pass

time.sleep(2) #delay before sending next command

data = "Green" #Set data to Blue Command

client_socket.sendto(data, address) #send command to arduino

try:

rec_data, addr = client_socket.recvfrom(2048) #Read response from arduino

print rec_data #Print the response from Arduino

except:

pass

time.sleep(2) #delay before sending next command

Again, this is a bit of a tricky thing to set up, but if you get the PC successfully pinging the arduino, everything else should be straightforward.

Technology Tutorials

Tag Archives: Server

Improved Client Server Framework for Arduino

Create a Simple Client Server Connection Over WiFi to Connect Arduino to Python on the PC

Python with Arduino LESSON 16: Simple Client Server Configuration over Ethernet

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