In this video lesson we explore a project where control access to a servo is activated by an RDID tag. In order to position the servo with the pushbuttons, the system must be unlocked by a RDID tag. When the system is locked, the LED is red, when the system is unlocked, the LED is green. 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.

RFID-SERVO — This schematic allows servo control to be granted via RFID tag

For your convenience, this is the code we developed below.

from mfrc522 import SimpleMFRC522
import time
import ujson
from machine import Pin, PWM
unlockTime = 5
decPin = 20
incPin = 21
servoPin=0
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

myServo=PWM(Pin(servoPin))
myServo.freq(50)
servoAngle=0

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

try:
    f=open("/dict.json","r")
    servoDict=ujson.load(f)
    f.close()
except:
    myDict={}
    f=open('dict.json','w')
    ujson.dump(myDict,f)
    f.close()
def readRFID():
    global cardID,servoAngle
    print()
    print("System LOCKED")
    print("Reading . . . Please Place the Card")
    cardID,readText = reader.read()
    print()
    print("ID: ",cardID)
    try:
        f=open('/dict.json','r')
        servoDict = ujson.load(f)
        f.close()
        servoAngle=servoDict[cardID]
        print(servoAngle)
        moveServo()
    except:
        f=open('/dict.json','r')
        myDict=ujson.load(f)
        f.close()
        myDict[cardID]=servoAngle
        f = open('/dict.json','w')
        ujson.dump(myDict,f)
        f.close()
        moveServo()

def moveServo():
    writeVal = 6553/180*servoAngle + 1638
    myServo.duty_u16(int(writeVal))
    f=open('/dict.json','r')
    myDict =ujson.load(f)
    f.close()
    myDict[cardID]=servoAngle
    f=open('/dict.json','w')
    ujson.dump(myDict, f)
    f.close()
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:
            servoAngle=servoAngle + 10
            if servoAngle>180:
                servoAngle=180
            if servoAngle<0:
                servoAngle=0
            moveServo()
            unlockStart=time.time()
            time.sleep(.2)
        if decButState==0 and decButStateOld==1:
            servoAngle=servoAngle - 10
            if servoAngle>180:
                servoAngle=180
            if servoAngle<0:
                servoAngle=0
            moveServo()
            unlockStart=time.time()
            time.sleep(.2)
        incButStateOld=incButState
        decButStateOld=decButState

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from mfrc522 import SimpleMFRC522

import time

import ujson

from machine import Pin, PWM

unlockTime = 5

decPin = 20

incPin = 21

servoPin=0

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

myServo=PWM(Pin(servoPin))

myServo.freq(50)

servoAngle=0

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

try:

f=open("/dict.json","r")

servoDict=ujson.load(f)

f.close()

except:

myDict={}

f=open('dict.json','w')

ujson.dump(myDict,f)

f.close()

def readRFID():

global cardID,servoAngle

print()

print("System LOCKED")

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

cardID,readText = reader.read()

print()

print("ID: ",cardID)

try:

f=open('/dict.json','r')

servoDict = ujson.load(f)

f.close()

servoAngle=servoDict[cardID]

print(servoAngle)

moveServo()

except:

f=open('/dict.json','r')

myDict=ujson.load(f)

f.close()

myDict[cardID]=servoAngle

f = open('/dict.json','w')

ujson.dump(myDict,f)

f.close()

moveServo()

def moveServo():

writeVal = 6553/180*servoAngle + 1638

myServo.duty_u16(int(writeVal))

f=open('/dict.json','r')

myDict =ujson.load(f)

f.close()

myDict[cardID]=servoAngle

f=open('/dict.json','w')

ujson.dump(myDict, f)

f.close()

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:

servoAngle=servoAngle + 10

if servoAngle>180:

servoAngle=180

if servoAngle<0:

servoAngle=0

moveServo()

unlockStart=time.time()

time.sleep(.2)

if decButState==0 and decButStateOld==1:

servoAngle=servoAngle - 10

if servoAngle>180:

servoAngle=180

if servoAngle<0:

servoAngle=0

moveServo()

unlockStart=time.time()

time.sleep(.2)

incButStateOld=incButState

decButStateOld=decButState

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")

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")

Technology Tutorials

RFID Project to Lock and Unlock Control of Servo

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

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