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")

MicroPython, Raspberry Pi Pico

RFID Lock and Unlock Demonstration Project Raspberry Pi Pico W

May 13, 2025 admin

In this video lesson we explore using an RFID-RC522 and an RFID tag to lock and unlock our raspberry pi project. This demonstration will include an RGB LED which remains red while the system is locked, and then turns green when the system is unlocked by the RFID tag. Absence of user input, the system will lock again after 5 seconds. The following is the circuit diagram for the project:

When using the breadvolt, or any battery power supply on a breadboard project, do not turn the power supply on while the Raspberry Pi Pico 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. Or if you are going to connect the USB, first turn off the power supply.

For your convenience, the code for the project is included below:

from mfrc522 import SimpleMFRC522
import time
from machine import Pin, PWM
unlockTime = 5
decPin = 20
incPin = 21
decBut=Pin(decPin,Pin.IN,Pin.PULL_UP)
incBut=Pin(incPin,Pin.IN,Pin.PULL_UP)

redPin=15
greenPin=14
bluePin=13
redLED=Pin(redPin,Pin.OUT)
greenLED=Pin(greenPin,Pin.OUT)
blueLED=Pin(bluePin,Pin.OUT)
redLED.on()
greenLED.off()
blueLED.off()

incButState=1
incButStateOld=1

decButState=1
decButStateOld=1

butCount = 0

reader=SimpleMFRC522(spi_id=0,sck=18,miso=16,mosi=19,cs=17,rst=9)

def readRFID():
    global cardID
    print()
    print("System LOCKED")
    print("Reading . . . Please Place the Card")
    cardID,readText = reader.read()
    print()
    print("ID: ",cardID)
while True:
    redLED.on()
    greenLED.off()
    blueLED.off()
    readRFID()
    print("System Unlocked by Card: ",cardID)
    unlockStart= time.time()
    while time.time()-unlockStart<unlockTime:
        redLED.off()
        greenLED.on()
        incButState=incBut.value()
        decButState=decBut.value()
        if incButState==0 and incButStateOld==1:
            butCount=butCount+1
            print("Button Count: ",butCount)
            unlockStart=time.time()
            time.sleep(.2)
        if decButState==0 and decButStateOld==1:
            butCount=butCount-1
            print("Button Count: ",butCount)
            unlockStart=time.time()
            time.sleep(.2)
        incButStateOld=incButState
        decButStateOld=decButState

from mfrc522 import SimpleMFRC522

import time

from machine import Pin, PWM

unlockTime = 5

decPin = 20

incPin = 21

decBut=Pin(decPin,Pin.IN,Pin.PULL_UP)

incBut=Pin(incPin,Pin.IN,Pin.PULL_UP)

redPin=15

greenPin=14

bluePin=13

redLED=Pin(redPin,Pin.OUT)

greenLED=Pin(greenPin,Pin.OUT)

blueLED=Pin(bluePin,Pin.OUT)

redLED.on()

greenLED.off()

blueLED.off()

incButState=1

incButStateOld=1

decButState=1

decButStateOld=1

butCount = 0

reader=SimpleMFRC522(spi_id=0,sck=18,miso=16,mosi=19,cs=17,rst=9)

def readRFID():

global cardID

print()

print("System LOCKED")

print("Reading . . . Please Place the Card")

cardID,readText = reader.read()

print()

print("ID: ",cardID)

while True:

redLED.on()

greenLED.off()

blueLED.off()

readRFID()

print("System Unlocked by Card: ",cardID)

unlockStart= time.time()

while time.time()-unlockStart<unlockTime:

redLED.off()

greenLED.on()

incButState=incBut.value()

decButState=decBut.value()

if incButState==0 and incButStateOld==1:

butCount=butCount+1

print("Button Count: ",butCount)

unlockStart=time.time()

time.sleep(.2)

if decButState==0 and decButStateOld==1:

butCount=butCount-1

print("Button Count: ",butCount)

unlockStart=time.time()

time.sleep(.2)

incButStateOld=incButState

decButStateOld=decButState

MicroPython, Raspberry Pi Pico

Connecting and Using the RFID-RC522 RFID Tag in a Raspberry Pi Pico Project

May 5, 2025 admin

This lesson is a brief introduction to incorporating an RFID tag into your Raspberry Pi Pico W project. We will be using the RFID-RC522 module, and will show to how to both read and write RFID tags.

The schematic shows how to connect the RFID module to your Pi Pico project.

The schematic above includes the breadvolt power supply, which we will use later as the project advances in future lessons. Notice carefully the top jumpers on the breadvolt set to 5 Volts, and the lower jumpers are set as 3.3 volts.

This is an alternative view of the same schematic, showing the pin labels on the RFID module. Both these schematics are the same, you can use the one you find easiest.

As the project progresses, we will also add two pushbuttons and an RGB LED to the circuit. This is the schematic, which we will use in lesson 121.

MicroPython, Raspberry Pi Pico

Incorporating an Adafruit Ultimate GPS into your Raspberry Pi Pico W Project

May 2, 2025 admin

In this video lesson we will show you how to connect and begin to get data from your Raspberry Pi Pico W connected to an Adafruit Ultimate GPS. The circuit schematic presented below. Notice Tx on the Pi Pico goes to Rx on the GPS, and Rx on the Pi Pico goes to Tx on the GPS.

Pi Pico GPS — This schematic shows how to connect the Adafruit Ultimate GPS to the Raspberry Pi Pico W

Then this is our initial code which reads the data from the GPS one byte at a time and prints it. In future lessons we will explain how to get useful information from this data, but for now, this code will allow you to read the data:

from machine import Pin,I2C,UART
import time

GPS = UART(1, baudrate = 9600, tx=machine.Pin(8), rx=machine.Pin(9))

try:
    while True:
        if GPS.any():
            myChar=GPS.read(1).decode('utf-8')
            print(myChar, end="")
    
except KeyboardInterrupt:
    print("\n . . . Cleaning Up UART")
    GPS.deinit()
    time.sleep(1)
    print("Cleanly Exited UART")

from machine import Pin,I2C,UART

import time

GPS = UART(1, baudrate = 9600, tx=machine.Pin(8), rx=machine.Pin(9))

try:

while True:

if GPS.any():

myChar=GPS.read(1).decode('utf-8')

print(myChar, end="")

except KeyboardInterrupt:

print("\n . . . Cleaning Up UART")

GPS.deinit()

time.sleep(1)

print("Cleanly Exited UART")

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

Improved Client Server Framework for Arduino

RFID Lock and Unlock Demonstration Project Raspberry Pi Pico W

Connecting and Using the RFID-RC522 RFID Tag in a Raspberry Pi Pico Project

Incorporating an Adafruit Ultimate GPS into your Raspberry Pi Pico W Project

Parsing Comma Delimited Data Strings in Arduino

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