Tag Archives: RFID

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.

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

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:

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.

Technology Tutorials

Tag Archives: RFID

RFID Project to Lock and Unlock Control of Servo

RFID Lock and Unlock Demonstration Project Raspberry Pi Pico W

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

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