Category Archives: MicroPython

Parsing GPS NMEA Sentences With the Raspberry Pi Pico W

July 22, 2025 admin

In this video lesson I show you how to parse NMEA sentences using the Raspberry Pi Pico W. In our project our pico is connected to the Adafruit Ultimate GPS V3. For this lesson we are using the following schematic:

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

For your convenience, I have included the code below developed in the video:

# ====================================================================
# DISCLAIMER:
# This code is provided as-is for educational and experimental 
# purposes only. The author makes no representations or warranties of 
# any kind concerning the safety, suitability, or accuracy of this 
# code. Use at your own risk. The author assumes no liability for any 
# damages, system failures, security breaches, or network issues 
# resulting from the use or implementation of this script.
# ====================================================================

from machine import Pin,I2C,UART
import time
import _thread
dataLock = _thread.allocate_lock()
keepRunning = True
GPS = UART(1, baudrate=9600, tx=machine.Pin(8), rx=machine.Pin(9))
# The following line ensures that the GPS reports the GPVTG NMEA Sentence
GPS.write(b"$PMTK314,0,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n")
NMEAdata = {
    'GPGGA' : "",
    'GPGSA' : "",
    'GPRMC' : "",
    'GPVTG' : ""
    }
GPSdata = {
    'latDD' 	: 0,
    'lonDD'		: 0,
    'heading'	: 0,
    'fix'		: False,
    'sats'		: 0,
    'knots'		: 0
    }
def gpsThread():
    print("Thread Running")
    global keepRunning,NMEAdata
    GPGGA = ""
    GPGSA = ""
    GPRMC = ""
    GPVTG = ""
    while not GPS.any():
        pass
    while GPS.any():
        junk = GPS.read()
        print(junk)
    myNMEA = ""
    while keepRunning:
        if GPS.any():
            myChar=GPS.read(1).decode('utf-8')
            myNMEA = myNMEA + myChar
            if myChar == '\n':
                myNMEA = myNMEA.strip()
                if myNMEA[1:6] == "GPGGA":
                    GPGGA = myNMEA
                if myNMEA[1:6] == "GPGSA":
                    GPGSA = myNMEA
                if myNMEA[1:6] == "GPRMC":
                    GPRMC = myNMEA
                if myNMEA[1:6] == "GPVTG":
                    GPVTG = myNMEA
                if GPGGA != "" and GPGSA!="" and GPRMC!="" and GPVTG!="":
                    dataLock.acquire()
                    NMEAdata = {
                        'GPGGA' : GPGGA,
                        'GPGSA' : GPGSA,
                        'GPRMC' : GPRMC,
                        'GPVTG' : GPVTG
                        }
                    dataLock.release()
                myNMEA = ""
    print("Thread Terminated Cleanly")
def parseGPS():
    readFix=int(NMEAmain['GPGGA'].split(',')[6])
    if readFix !=0:
        GPSdata['fix'] = True
        latRAW = NMEAmain['GPGGA'].split(',')[2]
        latDD = int(latRAW[0:2]) + float(latRAW[2:])/60
        if NMEAmain['GPGGA'].split(',')[3] == 'S':
            latDD = -latDD
        GPSdata['latDD']= latDD
        lonRAW=NMEAmain['GPGGA'].split(',')[4]
        lonDD=int(lonRAW[0:3]) + float(lonRAW[3:])/60
        if NMEAmain['GPGGA'].split(',')[5] == 'W':
            lonDD = -lonDD
        GPSdata['lonDD'] = lonDD
        heading = float(NMEAmain['GPRMC'].split(',')[8])
        GPSdata['heading'] = heading
        knots = float(NMEAmain['GPRMC'].split(',')[7])
        GPSdata['knots'] = knots
        sats = NMEAmain['GPGGA'].split(',')[7]
        GPSdata['sats'] = sats
        
        
_thread.start_new_thread(gpsThread,())
ts=2
time.sleep(ts)
try:
    while True:
        dataLock.acquire()
        NMEAmain = NMEAdata.copy()
        dataLock.release()
        parseGPS()
        if GPSdata['fix'] == False:
            print("Waiting for Fix . . .")
        if GPSdata['fix'] == True:
            print("Ultimate GPS Tracker Report: ")
            print("Lat and Lon: ",GPSdata['latDD'],GPSdata['lonDD'])
            print("Knots: ",GPSdata['knots'])
            print("Heading: ",GPSdata['heading'])
            print("Sats: ",GPSdata['sats'])
            print()
        ts=10
        time.sleep(ts)
except KeyboardInterrupt:
    print("\nStopping Program . . . Cleaning Up UART")
    keepRunning = False
    ts=1
    time.sleep(ts)
    GPS.deinit()
    time.sleep(ts)
    print("Exited Cleanly")

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

# ====================================================================

# DISCLAIMER:

# This code is provided as-is for educational and experimental

# purposes only. The author makes no representations or warranties of

# any kind concerning the safety, suitability, or accuracy of this

# code. Use at your own risk. The author assumes no liability for any

# damages, system failures, security breaches, or network issues

# resulting from the use or implementation of this script.

# ====================================================================

from machine import Pin,I2C,UART

import time

import _thread

dataLock = _thread.allocate_lock()

keepRunning = True

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

# The following line ensures that the GPS reports the GPVTG NMEA Sentence

GPS.write(b"$PMTK314,0,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n")

NMEAdata = {

'GPGGA' : "",

'GPGSA' : "",

'GPRMC' : "",

'GPVTG' : ""

}

GPSdata = {

'latDD' : 0,

'lonDD' : 0,

'heading' : 0,

'fix' : False,

'sats' : 0,

'knots' : 0

}

def gpsThread():

print("Thread Running")

global keepRunning,NMEAdata

GPGGA = ""

GPGSA = ""

GPRMC = ""

GPVTG = ""

while not GPS.any():

pass

while GPS.any():

junk = GPS.read()

print(junk)

myNMEA = ""

while keepRunning:

if GPS.any():

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

myNMEA = myNMEA + myChar

if myChar == '\n':

myNMEA = myNMEA.strip()

if myNMEA[1:6] == "GPGGA":

GPGGA = myNMEA

if myNMEA[1:6] == "GPGSA":

GPGSA = myNMEA

if myNMEA[1:6] == "GPRMC":

GPRMC = myNMEA

if myNMEA[1:6] == "GPVTG":

GPVTG = myNMEA

if GPGGA != "" and GPGSA!="" and GPRMC!="" and GPVTG!="":

dataLock.acquire()

NMEAdata = {

'GPGGA' : GPGGA,

'GPGSA' : GPGSA,

'GPRMC' : GPRMC,

'GPVTG' : GPVTG

}

dataLock.release()

myNMEA = ""

print("Thread Terminated Cleanly")

def parseGPS():

readFix=int(NMEAmain['GPGGA'].split(',')[6])

if readFix !=0:

GPSdata['fix'] = True

latRAW = NMEAmain['GPGGA'].split(',')[2]

latDD = int(latRAW[0:2]) + float(latRAW[2:])/60

if NMEAmain['GPGGA'].split(',')[3] == 'S':

latDD = -latDD

GPSdata['latDD']= latDD

lonRAW=NMEAmain['GPGGA'].split(',')[4]

lonDD=int(lonRAW[0:3]) + float(lonRAW[3:])/60

if NMEAmain['GPGGA'].split(',')[5] == 'W':

lonDD = -lonDD

GPSdata['lonDD'] = lonDD

heading = float(NMEAmain['GPRMC'].split(',')[8])

GPSdata['heading'] = heading

knots = float(NMEAmain['GPRMC'].split(',')[7])

GPSdata['knots'] = knots

sats = NMEAmain['GPGGA'].split(',')[7]

GPSdata['sats'] = sats

_thread.start_new_thread(gpsThread,())

ts=2

time.sleep(ts)

try:

while True:

dataLock.acquire()

NMEAmain = NMEAdata.copy()

dataLock.release()

parseGPS()

if GPSdata['fix'] == False:

print("Waiting for Fix . . .")

if GPSdata['fix'] == True:

print("Ultimate GPS Tracker Report: ")

print("Lat and Lon: ",GPSdata['latDD'],GPSdata['lonDD'])

print("Knots: ",GPSdata['knots'])

print("Heading: ",GPSdata['heading'])

print("Sats: ",GPSdata['sats'])

print()

ts=10

time.sleep(ts)

except KeyboardInterrupt:

print("\nStopping Program . . . Cleaning Up UART")

keepRunning = False

ts=1

time.sleep(ts)

GPS.deinit()

time.sleep(ts)

print("Exited Cleanly")

MicroPython, Raspberry Pi Pico, Tutorial

Getting Latitude and Longitude from the Adafruit Ultimate GPS with Raspberry Pi Pico W

July 1, 2025 admin

In this video lesson I show how to get usable Latitude and Longitude from the Adafruit Ultimate GPS version 3 using the Raspberry Pi Pico W. We read the NMEA sentences from the GPS, we parse them into individual strings for each sentence, and then we create arrays of data from the strings. Then we begin to parse the arrays, and convert the confusing numbers into useful Decimal Degree values for Latitude and Longitude.

For your convenience, this is the code we developed in todays lesson:

# ====================================================================
# DISCLAIMER:
# This code is provided as-is for educational and experimental 
# purposes only. The author makes no representations or warranties of 
# any kind concerning the safety, suitability, or accuracy of this 
# code. Use at your own risk. The author assumes no liability for any 
# damages, system failures, security breaches, or network issues 
# resulting from the use or implementation of this script.
# ====================================================================
from machine import Pin,I2C,UART  #***************
import time
GPS = UART(1, baudrate=9600, tx=machine.Pin(8), rx=machine.Pin(9))
# The following line ensures that the GPS reports the GPVTG NMEA Sentence
GPS.write(b"$PMTK314,0,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n")
myNMEA=""
GPGGA=""
GPGSA=""
GPRMC=""
GPVTG=""
GPGSV=""
while not GPS.any():
    pass
while GPS.any():
    junk=GPS.read()
    print(junk)
try:
    while True:
        if GPS.any():
            #myChar=GPS.read(1)
            myChar=GPS.read(1).decode('utf-8')
            myNMEA=myNMEA+myChar
            if myChar=='\n':
                if myNMEA[1:6]=="GPGGA":
                    GPGGA=myNMEA
                    GPGGAarray=GPGGA.split(',')
                    #print(GPGGA)
                    #print(GPGGAarray)
                    if int(GPGGAarray[6]) != 0:
                        latRAW=GPGGAarray[2]
                        lonRAW=GPGGAarray[4]
                        numSat=int(GPGGAarray[7])
                        latDD=int(latRAW[0:2])+float(latRAW[2:])/60
                        lonDD=int(lonRAW[0:3])+float(lonRAW[3:])/60
                        if GPGGAarray[3]=='S':
                            latDD=-latDD
                        if GPGGAarray[5]=='W':
                            lonDD=-lonDD
                        print("LAT, LON, numSat ",latDD,lonDD,numSat)
                if myNMEA[1:6]=="GPGSA":
                    GPGSA=myNMEA
                    GPGSAarray=GPGSA.split(',')
                if myNMEA[1:6]=="GPRMC":
                    GPRMC=myNMEA
                    GPRMCarray=GPRMC.split(',')
                    knots=float(GPRMCarray[7])
                    heading=float(GPRMCarray[8])
                    print(knots, "Knots at a Heading of: ",heading)
                if myNMEA[1:6]=="GPVTG":
                    GPVTG=myNMEA
                    GPVTGarray=GPVTG.split(',')
                if myNMEA[1:6]=="GPGSV":
                    GPGSV=myNMEA
                    GPGSVarray=GPGSV.split(',')
                    if GPGGA!="":
                        if int(GPGGAarray[6])==0:
                            print('Aquiring Fix:', GPGSVarray[3], "Sattellites in View")
                                              
                myNMEA=""
except KeyboardInterrupt:
    print("\nStopping program... Cleaning up UART.")
    GPS.deinit()  # Properly release UART before exit
    ts=1
    time.sleep(ts)  # Short pause to ensure clean shutdown
    print("Exited cleanly.")

# ====================================================================

# DISCLAIMER:

# This code is provided as-is for educational and experimental

# purposes only. The author makes no representations or warranties of

# any kind concerning the safety, suitability, or accuracy of this

# code. Use at your own risk. The author assumes no liability for any

# damages, system failures, security breaches, or network issues

# resulting from the use or implementation of this script.

# ====================================================================

from machine import Pin,I2C,UART #***************

import time

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

# The following line ensures that the GPS reports the GPVTG NMEA Sentence

GPS.write(b"$PMTK314,0,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n")

myNMEA=""

GPGGA=""

GPGSA=""

GPRMC=""

GPVTG=""

GPGSV=""

while not GPS.any():

pass

while GPS.any():

junk=GPS.read()

print(junk)

try:

while True:

if GPS.any():

#myChar=GPS.read(1)

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

myNMEA=myNMEA+myChar

if myChar=='\n':

if myNMEA[1:6]=="GPGGA":

GPGGA=myNMEA

GPGGAarray=GPGGA.split(',')

#print(GPGGA)

#print(GPGGAarray)

if int(GPGGAarray[6]) != 0:

latRAW=GPGGAarray[2]

lonRAW=GPGGAarray[4]

numSat=int(GPGGAarray[7])

latDD=int(latRAW[0:2])+float(latRAW[2:])/60

lonDD=int(lonRAW[0:3])+float(lonRAW[3:])/60

if GPGGAarray[3]=='S':

latDD=-latDD

if GPGGAarray[5]=='W':

lonDD=-lonDD

print("LAT, LON, numSat ",latDD,lonDD,numSat)

if myNMEA[1:6]=="GPGSA":

GPGSA=myNMEA

GPGSAarray=GPGSA.split(',')

if myNMEA[1:6]=="GPRMC":

GPRMC=myNMEA

GPRMCarray=GPRMC.split(',')

knots=float(GPRMCarray[7])

heading=float(GPRMCarray[8])

print(knots, "Knots at a Heading of: ",heading)

if myNMEA[1:6]=="GPVTG":

GPVTG=myNMEA

GPVTGarray=GPVTG.split(',')

if myNMEA[1:6]=="GPGSV":

GPGSV=myNMEA

GPGSVarray=GPGSV.split(',')

if GPGGA!="":

if int(GPGGAarray[6])==0:

print('Aquiring Fix:', GPGSVarray[3], "Sattellites in View")

myNMEA=""

except KeyboardInterrupt:

print("\nStopping program... Cleaning up UART.")

GPS.deinit() # Properly release UART before exit

ts=1

time.sleep(ts) # Short pause to ensure clean shutdown

print("Exited cleanly.")

MicroPython, Raspberry Pi Pico

Connecting the Adafruit Ultimate GPS to the Raspberry Pi Pico W

June 9, 2025 admin

In this video lesson we will connect the Adafruit Ultimate GPS to the Raspberry Pi Pico W, and will write a simple program to capture the data being sent by the GPS. In this lesson, we simply want to read and print the NMEA sentences coming off the GPS, and then in future lessons we will begin to parse the data, and turn the data into usable numbers. This is the schematic for connecting the GPS to your Raspberry Pi Pico W.

Then this is the simple code we developed to allow reading the data coming from the GPS.

from machine import Pin,I2C,UART  #***************
import time

GPS = UART(1, baudrate=9600, tx=machine.Pin(8), rx=machine.Pin(9))
# The following line ensures that the GPS reports the GPVTG NMEA Sentence
GPS.write(b"$PMTK314,0,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n")
try:
    while True:
        if GPS.any():
            #myChar=GPS.read(1)
            myChar=GPS.read(1).decode('utf-8')
            print(myChar, end="") #Supress the line feed, so It continues to print across
except KeyboardInterrupt:
    print("\nStopping program... Cleaning up UART.")
    GPS.deinit()  # Properly release UART before exit
    time.sleep(1)  # Short pause to ensure clean shutdown
    print("Exited cleanly.")

from machine import Pin,I2C,UART #***************

import time

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

# The following line ensures that the GPS reports the GPVTG NMEA Sentence

GPS.write(b"$PMTK314,0,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n")

try:

while True:

if GPS.any():

#myChar=GPS.read(1)

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

print(myChar, end="") #Supress the line feed, so It continues to print across

except KeyboardInterrupt:

print("\nStopping program... Cleaning up UART.")

GPS.deinit() # Properly release UART before exit

time.sleep(1) # Short pause to ensure clean shutdown

print("Exited cleanly.")

MicroPython, Raspberry Pi Pico

RFID Project to Lock and Unlock Control of Servo

May 20, 2025 admin

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.

# ====================================================================
# DISCLAIMER:
# This code is provided as-is for educational and experimental 
# purposes only. The author makes no representations or warranties of 
# any kind concerning the safety, suitability, or accuracy of this 
# code. Use at your own risk. The author assumes no liability for any 
# damages, system failures, security breaches, or network issues 
# resulting from the use or implementation of this script.
# ====================================================================

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()
            ts=.2
            time.sleep(ts)
        if decButState==0 and decButStateOld==1:
            servoAngle=servoAngle - 10
            if servoAngle>180:
                servoAngle=180
            if servoAngle<0:
                servoAngle=0
            moveServo()
            unlockStart=time.time()
            ts=.2
            time.sleep(.2)
        incButStateOld=incButState
        decButStateOld=decButState

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

# ====================================================================

# DISCLAIMER:

# This code is provided as-is for educational and experimental

# purposes only. The author makes no representations or warranties of

# any kind concerning the safety, suitability, or accuracy of this

# code. Use at your own risk. The author assumes no liability for any

# damages, system failures, security breaches, or network issues

# resulting from the use or implementation of this script.

# ====================================================================

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()

ts=.2

time.sleep(ts)

if decButState==0 and decButStateOld==1:

servoAngle=servoAngle - 10

if servoAngle>180:

servoAngle=180

if servoAngle<0:

servoAngle=0

moveServo()

unlockStart=time.time()

ts=.2

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:

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:

# ====================================================================
# DISCLAIMER:
# This code is provided as-is for educational and experimental 
# purposes only. The author makes no representations or warranties of 
# any kind concerning the safety, suitability, or accuracy of this 
# code. Use at your own risk. The author assumes no liability for any 
# damages, system failures, security breaches, or network issues 
# resulting from the use or implementation of this script.
# ====================================================================

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()
            ts=.2
            time.sleep(ts)
        if decButState==0 and decButStateOld==1:
            butCount=butCount-1
            print("Button Count: ",butCount)
            unlockStart=time.time()
            ts=.2
            time.sleep(ts)
        incButStateOld=incButState
        decButStateOld=decButState

# ====================================================================

# DISCLAIMER:

# This code is provided as-is for educational and experimental

# purposes only. The author makes no representations or warranties of

# any kind concerning the safety, suitability, or accuracy of this

# code. Use at your own risk. The author assumes no liability for any

# damages, system failures, security breaches, or network issues

# resulting from the use or implementation of this script.

# ====================================================================

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()

ts=.2

time.sleep(ts)

if decButState==0 and decButStateOld==1:

butCount=butCount-1

print("Button Count: ",butCount)

unlockStart=time.time()

ts=.2

time.sleep(ts)

incButStateOld=incButState

decButStateOld=decButState

Technology Tutorials

Category Archives: MicroPython

Parsing GPS NMEA Sentences With the Raspberry Pi Pico W

Getting Latitude and Longitude from the Adafruit Ultimate GPS with Raspberry Pi Pico W

Connecting the Adafruit Ultimate GPS to the Raspberry Pi Pico W

RFID Project to Lock and Unlock Control of Servo

RFID Lock and Unlock Demonstration Project Raspberry Pi Pico W

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