Tag Archives: UDP

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. Then the Pico sets that color to ‘ON’. The pi pico is powered by a breadboard power bank, and there is no need for any connections to the pico. You can pick up the breadBoard Power Bank HERE [Affiliate Link]. Below is the schematic for the Server Side of the project:

Schematic for Circuit to Demonstrate a Client Server Example on Pi Pico

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

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
while not wlan.isconnected():
    time.sleep(1)
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(1)

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

while not wlan.isconnected():

time.sleep(1)

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(1)

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

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())

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())

Python, Raspberry Pi Pico

Sending Data Over WiFi Between Raspberry Pi Pico W and Your PC

February 18, 2025 admin

In this video lesson we show how we can send and receive data between the Raspberry Pi Pico W, and your PC. We will be running python on the PC, and we will exchange data using the UDP protocol. UDP is simple, and a very reliable way to send data packets back and forth. In this example, we will be demonstrating a simple Client Server relationship between the Pi Pico and PC using UDP over WiFi.

In this lesson, we will just be showing simple exchange of data, but in preparation for future lessons, go ahead and build this circuit.

For your convenience, this is the “Server” software you will run on the Pi Pico.

import network
import usocket as socket
import secrets
import time

wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect(secrets.SSID,secrets.PASSWORD)

# Wait for connection
while not wlan.isconnected():
    time.sleep(1)
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
    request, client_address = server_socket.recvfrom(1024)
    print("Client Request:",request.decode())
    print("FROM CLIENT",client_address)
    
    # String to send
    data = "225,128,64"
    
    # Send data to client
    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(1)

import network

import usocket as socket

import secrets

import time

wlan = network.WLAN(network.STA_IF)

wlan.active(True)

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

# Wait for connection

while not wlan.isconnected():

time.sleep(1)

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

request, client_address = server_socket.recvfrom(1024)

print("Client Request:",request.decode())

print("FROM CLIENT",client_address)

# String to send

data = "225,128,64"

# Send data to client

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(1)

Notice that the above code wants to load a “secrets” file that contain your WiFi name, and password

You should edit the code below with your WiFi username and your password, and then save the file in the Pi Pico lib folder, with the name secrets.py (don’t forget the .py)

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

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

Now, on the PC side, you will run your client, which will be run in Python. Here is the client software:

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
    request_message = "SEND DATA"
    client_socket.sendto(request_message.encode(), server_address)
    
    # Receive data from the server
    data, addr = client_socket.recvfrom(1024)
    print('Received data:', data.decode())
    
    # Send acknowledgment back to server
    #ack_message = "Data received successfully"
    #client_socket.sendto(ack_message.encode(), addr)
    
    # Wait for 10 seconds before next request
    time.sleep(10)

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

request_message = "SEND DATA"

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

# Receive data from the server

data, addr = client_socket.recvfrom(1024)

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

# Send acknowledgment back to server

#ack_message = "Data received successfully"

#client_socket.sendto(ack_message.encode(), addr)

# Wait for 10 seconds before next request

time.sleep(10)

Arduino with Python, Tutorial

Python with Arduino LESSON 17: Sending and Receiving Data Over Ethernet

April 6, 2015 admin

This circuit contains an Arduino Nano and Pressure Sensor Communicating over Ethernet

In LESSON 16 we showed a simple Client Server model that allows us to send strings between Python running on a PC and the arduino over Ethernet. That lesson simply passed strings back and forth to show a very basic Server on Arduino, and Python acting as the Client. In this lesson we show a more practical example, with the Arduino connected to an Adafruit BMP180 Pressure Sensor. In order to complete this lesson, you will need an Arduino, an Ethernet Shield, and the Pressure Sensor. If you do not have this particular pressure sensor, you can probably follow along in the lesson using whatever sensor you have that is of interest. The video will take you through the tutorial step-by-step, and then the code we developed is shown below.

The key issue in getting this project to work is to get your mac address and IP address from your router or network. If you are at school, simply speak to your network administrator, and he will help you get an IP address for your arduino. If you are at home, you will need to connect to your router from a browser, and configure it to assign an IP address and agree on a mac address for your arduino. 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. There are thousands of possible routers and networks out there, so I can not help you with that part. But if you look in the router documentation, you should be able to get the IP address and mac address worked out. The arduino itself does not have a hard wired mac address, but you set the mac address in the arduino software, and the IP address as well. The key thing is that the mac address is unique on your network, and the router and arduino agree on the IP address and mac address. If you have a clearer way to explain this, please leave a comment below.

This is the server side software to run on the arduino. Again, you should use a suitable IP address and mac address for your network. Do not think you can just copy the ones I use in the code below.

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

#include "Wire.h" //imports the wire library
#include "Adafruit_BMP085.h" // import the Pressure/Temperature sensor library
Adafruit_BMP085 mySensor; //Create a sensor object

float tempC; //Declare variable for Temp in C
float tempF; //Declare variable for Temp in F
float Pressure; //Declare a variable for Pressure

byte mac[] ={ 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xEE}; //Assign mac address
IPAddress ip(10, 1, 15, 243); //Assign the IP Adress
unsigned int localPort = 5000; // Assign a port to talk over
char packetBuffer[UDP_TX_PACKET_MAX_SIZE]; //dimensian a char array to hold our data packet
String datReq; //String for our data
int packetSize; //Size of the packet
EthernetUDP Udp; // Create a UDP Object

void setup() {
  
  Serial.begin(9600); //Initialize Serial Port 
  Ethernet.begin( mac, ip); //Inialize the Ethernet
  Udp.begin(localPort); //Initialize Udp
  delay(1500); //delay
  mySensor.begin(); //initialize pressure-temp sensor
  

}

void loop() {
  
  packetSize =Udp.parsePacket(); //Reads the packet size
  
  if(packetSize>0) { //if packetSize is >0, that means someone has sent a request
    
    Udp.read(packetBuffer, UDP_TX_PACKET_MAX_SIZE); //Read the data request
    String datReq(packetBuffer); //Convert char array packetBuffer into a string called datReq
    
    if (datReq =="Temperature") { //Do the following if Temperature is requested
    
      tempC = mySensor.readTemperature(); //Read the temperature
      tempF = tempC*1.8 + 32; //Convert temp to F
      
      Udp.beginPacket(Udp.remoteIP(), Udp.remotePort()); //Initialize packet send
      Udp.print(tempF); //Send the temperature data
      Udp.endPacket(); //End the packet
      
    }
    
    if (datReq== "Pressure") { //Do the following if Pressure is requested
    
      Pressure=mySensor.readPressure(); //read the pressure
      
        Udp.beginPacket(Udp.remoteIP(), Udp.remotePort()); //Initialize packet send
        Udp.print(Pressure); //Send the Pressure data
        Udp.endPacket(); //End the packet
        
    }
      
  }
  memset(packetBuffer, 0, UDP_TX_PACKET_MAX_SIZE); //clear out the packetBuffer array
}

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

#include <EthernetUdp.h> //Load the Udp Library

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

#include "Wire.h" //imports the wire library

#include "Adafruit_BMP085.h" // import the Pressure/Temperature sensor library

Adafruit_BMP085 mySensor; //Create a sensor object

float tempC; //Declare variable for Temp in C

float tempF; //Declare variable for Temp in F

float Pressure; //Declare a variable for Pressure

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

IPAddress ip(10, 1, 15, 243); //Assign the IP Adress

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

char packetBuffer[UDP_TX_PACKET_MAX_SIZE]; //dimensian a char array to hold our data packet

String datReq; //String for our data

int packetSize; //Size of the packet

EthernetUDP Udp; // Create a UDP Object

void setup() {

Serial.begin(9600); //Initialize Serial Port

Ethernet.begin( mac, ip); //Inialize the Ethernet

Udp.begin(localPort); //Initialize Udp

delay(1500); //delay

mySensor.begin(); //initialize pressure-temp sensor

}

void loop() {

packetSize =Udp.parsePacket(); //Reads the packet size

if(packetSize>0) { //if packetSize is >0, that means someone has sent a request

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

String datReq(packetBuffer); //Convert char array packetBuffer into a string called datReq

if (datReq =="Temperature") { //Do the following if Temperature is requested

tempC = mySensor.readTemperature(); //Read the temperature

tempF = tempC*1.8 + 32; //Convert temp to F

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

Udp.print(tempF); //Send the temperature data

Udp.endPacket(); //End the packet

}

if (datReq== "Pressure") { //Do the following if Pressure is requested

Pressure=mySensor.readPressure(); //read the pressure

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

Udp.print(Pressure); //Send the Pressure data

Udp.endPacket(); //End the packet

}

memset(packetBuffer, 0, UDP_TX_PACKET_MAX_SIZE); //clear out the packetBuffer array

}

Once you have this on your arduino, and the arduino connected to the internet via an Ethernet cable, you can test by opening a command line in Windows. Then ping the address you have assigned to the Arduino. If it pings correctly and you get a reply, you are ready to develop the Python code. The Python will be the client. It will send the requests to the Arduino, and the Arduino will respond with data. Since our circuit can measure pressure or temperature, you can request either of those. When the arduino receives a request for temperature, it will go out, make the temperature measurement and then return the data to Python. Similarly, if you request Pressure the arduino will read the request, will make the Pressure measurement, and then return pressure reading to the client (Python).

from socket import *
import time

address= ( '10.1.15.243', 5000) #define server IP and port
client_socket =socket(AF_INET, SOCK_DGRAM) #Set up the Socket
client_socket.settimeout(1) #Only wait 1 second for a response

while(1):

    data = "Temperature" #Set data request to Temperature

    client_socket.sendto( data, address) #Send the data request

    try:

        rec_data, addr = client_socket.recvfrom(2048) #Read response from arduino
        temp = float(rec_data) #Convert string rec_data to float temp
        print "The Measured Temperature is ", temp, " degrees F." # Print the result

    except:
        pass

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

    data = "Pressure" #Set data request to Pressure

    client_socket.sendto( data, address) #Send the data request

    try:

        rec_data, addr = client_socket.recvfrom(2048) #Read response from arduino
        Pressure = float(rec_data) #Convert string rec_data to float temp
        print "The Measured Pressure is ", Pressure, " Pa." # Print the result

    except:
        pass

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

    print ""

from socket import *

import time

address= ( '10.1.15.243', 5000) #define server IP and port

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

client_socket.settimeout(1) #Only wait 1 second for a response

while(1):

data = "Temperature" #Set data request to Temperature

client_socket.sendto( data, address) #Send the data request

try:

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

temp = float(rec_data) #Convert string rec_data to float temp

print "The Measured Temperature is ", temp, " degrees F." # Print the result

except:

pass

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

data = "Pressure" #Set data request to Pressure

client_socket.sendto( data, address) #Send the data request

try:

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

Pressure = float(rec_data) #Convert string rec_data to float temp

print "The Measured Pressure is ", Pressure, " Pa." # Print the result

except:

pass

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

print ""

This python code will request Temperature, will then read the response, and then will print the data. It then requests Pressure, reads the response, and then prints it. If you look at our earlier lessons you can see graphical techniques to visually present the data. The hard part is getting the data passed back and forth, which we show how to do in this lesson.

Technology Tutorials

Tag Archives: UDP

Simple Client Server Project for the Raspberry Pi Pico W

Sending Data Over WiFi Between Raspberry Pi Pico W and Your PC

Python with Arduino LESSON 17: Sending and Receiving Data Over Ethernet

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