Tag Archives: LCD

Raspberry Pi LESSON 37: Raspberry Pi Security System

November 24, 2022 admin

In this lesson we add an audible alarm to our security system. I am connecting to a Bluetooth speaker, and then using the pygame library to play an alarm sound. The pygame library will play any .mp3 file, so search the internet and find a suitable alarm sound for your system. I amusing an air raid siren, and really like it! Below for your convenience is the code we develop in this video:

import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BOARD)
PIRpin=12
GPIO.setup(PIRpin,GPIO.IN)
import LCD1602
import KPLIB
from time import sleep
import threading
myPad=KPLIB.keypad(retChar='D')
LCD1602.init(0x27,1)
myString=''
pwd='1234'

from pygame import mixer
mixer.init()
mixer.music.load('alarm.mp3')

def readKP():
    global myString
    while myString != '*':
        myString=myPad.readKeypad()
        sleep(.5)
readThread=threading.Thread(target=readKP,)
readThread.daemon=True
readThread.start()
while myString != '*':
    CMD=myString
    if CMD=='A'+pwd:
        LCD1602.write(0,0,'Armed          ')
        moveVal=GPIO.input(PIRpin)
        if moveVal==1:
            LCD1602.write(0,1,'Intruder Alert')
            mixer.music.play()
            sleep(10)
        if moveVal==0:
            LCD1602.write(0,1,'All Clear      ')
    if CMD=='B'+pwd:
        LCD1602.write(0,0,'UnArmed        ')
        LCD1602.write(0,1,'               ')
    if CMD=='C'+pwd:
        LCD1602.write(0,0,'Password?      ')
        LCD1602.write(0,1,'               ')
        while myString=='C'+pwd:
            pass
        pwd=myString
        LCD1602.write(0,0,pwd+'         ')
        sleep(2)
        LCD1602.write(0,0,'               ')
        LCD1602.clear()
sleep(1)
GPIO.cleanup()
LCD1602.clear()
print('GPIO Good to Go')

import RPi.GPIO as GPIO

GPIO.setmode(GPIO.BOARD)

PIRpin=12

GPIO.setup(PIRpin,GPIO.IN)

import LCD1602

import KPLIB

from time import sleep

import threading

myPad=KPLIB.keypad(retChar='D')

LCD1602.init(0x27,1)

myString=''

pwd='1234'

from pygame import mixer

mixer.init()

mixer.music.load('alarm.mp3')

def readKP():

global myString

while myString != '*':

myString=myPad.readKeypad()

sleep(.5)

readThread=threading.Thread(target=readKP,)

readThread.daemon=True

readThread.start()

while myString != '*':

CMD=myString

if CMD=='A'+pwd:

LCD1602.write(0,0,'Armed ')

moveVal=GPIO.input(PIRpin)

if moveVal==1:

LCD1602.write(0,1,'Intruder Alert')

mixer.music.play()

sleep(10)

if moveVal==0:

LCD1602.write(0,1,'All Clear ')

if CMD=='B'+pwd:

LCD1602.write(0,0,'UnArmed ')

LCD1602.write(0,1,' ')

if CMD=='C'+pwd:

LCD1602.write(0,0,'Password? ')

LCD1602.write(0,1,' ')

while myString=='C'+pwd:

pass

pwd=myString

LCD1602.write(0,0,pwd+' ')

sleep(2)

LCD1602.write(0,0,' ')

LCD1602.clear()

sleep(1)

GPIO.cleanup()

LCD1602.clear()

print('GPIO Good to Go')

Raspberry Pi

Raspberry Pi LESSON 36: Motion Detection Alarm System With LCD and Keypad

November 10, 2022 admin

In this lesson we show the basic framework for an Alarm System with operator control through a keypad, and output to an LCD screen. We incorporate a PIR sensor to detect motion. In the next lesson we will add an audible alarm. For your convenience, the code developed in the above video is included below:

import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BOARD)
PIRpin=12
GPIO.setup(PIRpin,GPIO.IN)
import LCD1602
import KPLIB
from time import sleep
import threading
myPad=KPLIB.keypad(retChar='D')
LCD1602.init(0x27,1)
myString=''
pwd='1234'
def readKP():
    global myString
    while myString != '*':
        myString=myPad.readKeypad()
        sleep(.5)
readThread=threading.Thread(target=readKP,)
readThread.daemon=True
readThread.start()
while myString != '*':
    CMD=myString
    if CMD=='A'+pwd:
        LCD1602.write(0,0,'Armed          ')
        moveVal=GPIO.input(PIRpin)
        if moveVal==1:
            LCD1602.write(0,1,'Intruder Alert')
        if moveVal==0:
            LCD1602.write(0,1,'All Clear      ')
    if CMD=='B'+pwd:
        LCD1602.write(0,0,'UnArmed        ')
        LCD1602.write(0,1,'               ')
    if CMD=='C'+pwd:
        LCD1602.write(0,0,'Password?      ')
        LCD1602.write(0,1,'               ')
        while myString=='C'+pwd:
            pass
        pwd=myString
        LCD1602.write(0,0,pwd+'         ')
        sleep(2)
        LCD1602.write(0,0,'               ')
        LCD1602.clear()
sleep(1)
GPIO.cleanup()
LCD1602.clear()
print('GPIO Good to Go')

import RPi.GPIO as GPIO

GPIO.setmode(GPIO.BOARD)

PIRpin=12

GPIO.setup(PIRpin,GPIO.IN)

import LCD1602

import KPLIB

from time import sleep

import threading

myPad=KPLIB.keypad(retChar='D')

LCD1602.init(0x27,1)

myString=''

pwd='1234'

def readKP():

global myString

while myString != '*':

myString=myPad.readKeypad()

sleep(.5)

readThread=threading.Thread(target=readKP,)

readThread.daemon=True

readThread.start()

while myString != '*':

CMD=myString

if CMD=='A'+pwd:

LCD1602.write(0,0,'Armed ')

moveVal=GPIO.input(PIRpin)

if moveVal==1:

LCD1602.write(0,1,'Intruder Alert')

if moveVal==0:

LCD1602.write(0,1,'All Clear ')

if CMD=='B'+pwd:

LCD1602.write(0,0,'UnArmed ')

LCD1602.write(0,1,' ')

if CMD=='C'+pwd:

LCD1602.write(0,0,'Password? ')

LCD1602.write(0,1,' ')

while myString=='C'+pwd:

pass

pwd=myString

LCD1602.write(0,0,pwd+' ')

sleep(2)

LCD1602.write(0,0,' ')

LCD1602.clear()

sleep(1)

GPIO.cleanup()

LCD1602.clear()

print('GPIO Good to Go')

Raspberry Pi

Creating a programmable Temperature Alarm with the Raspberry Pi

September 22, 2022 admin

In this video lesson we show how to create a programmable temperature alarm using the Raspberry Pi, the DHT11 sensor, the ADC0834, a potentiometer and a buzzer. The results are displayed on a LCD1602 LCD display with a i2c connection. The device operates in either program mode or monitor mode. Pressing the button puts you in programming mode. In this mode you turn the potentiometer until your desired set temperature is reached. Then pressing the button again will switch you to monitor mode. In monitor mode the current temperature and humidity are displayed on the LCD. When the temperature exceeds your setpoint, the buzzer will release an audible alarm. Below is the schematic for our build.

This schematic shows how to create a programmable temperature alarm

Python, Raspberry Pi

Library for I2C Connection of the LCD1602 to the Raspberry PI

August 31, 2022 admin

This lesson shows how to connect an LCD1602 to a Raspberry Pi using only 4 wires by I2C. You will need to copy the code below, and create a program called LCD1602.py, and save it in the same folder your main python programs are in.

#!/usr/bin/env python3

import time
import smbus2 as smbus

BUS = smbus.SMBus(1)

def write_word(addr, data):
    global BLEN
    temp = data
    if BLEN == 1:
        temp |= 0x08
    else:
        temp &= 0xF7
    BUS.write_byte(addr ,temp)

def send_command(comm):
    # Send bit7-4 firstly
    buf = comm & 0xF0
    buf |= 0x04               # RS = 0, RW = 0, EN = 1
    write_word(LCD_ADDR ,buf)
    time.sleep(0.002)
    buf &= 0xFB               # Make EN = 0
    write_word(LCD_ADDR ,buf)

    # Send bit3-0 secondly
    buf = (comm & 0x0F) << 4
    buf |= 0x04               # RS = 0, RW = 0, EN = 1
    write_word(LCD_ADDR ,buf)
    time.sleep(0.002)
    buf &= 0xFB               # Make EN = 0
    write_word(LCD_ADDR ,buf)

def send_data(data):
    # Send bit7-4 firstly
    buf = data & 0xF0
    buf |= 0x05               # RS = 1, RW = 0, EN = 1
    write_word(LCD_ADDR ,buf)
    time.sleep(0.002)
    buf &= 0xFB               # Make EN = 0
    write_word(LCD_ADDR ,buf)

    # Send bit3-0 secondly
    buf = (data & 0x0F) << 4
    buf |= 0x05               # RS = 1, RW = 0, EN = 1
    write_word(LCD_ADDR ,buf)
    time.sleep(0.002)
    buf &= 0xFB               # Make EN = 0
    write_word(LCD_ADDR ,buf)

def init(addr, bl):
#    global BUS
#    BUS = smbus.SMBus(1)
    global LCD_ADDR
    global BLEN
    LCD_ADDR = addr
    BLEN = bl
    try:
        send_command(0x33) # Must initialize to 8-line mode at first
        time.sleep(0.005)
        send_command(0x32) # Then initialize to 4-line mode
        time.sleep(0.005)
        send_command(0x28) # 2 Lines & 5*7 dots
        time.sleep(0.005)
        send_command(0x0C) # Enable display without cursor
        time.sleep(0.005)
        send_command(0x01) # Clear Screen
        BUS.write_byte(LCD_ADDR, 0x08)
    except:
        return False
    else:
        return True

def clear():
    send_command(0x01) # Clear Screen

def openlight():  # Enable the backlight
    BUS.write_byte(0x27,0x08)
    BUS.close()

def write(x, y, str):
    if x < 0:
        x = 0
    if x > 15:
        x = 15
    if y <0:
        y = 0
    if y > 1:
        y = 1

    # Move cursor
    addr = 0x80 + 0x40 * y + x
    send_command(addr)

    for chr in str:
        send_data(ord(chr))

if __name__ == '__main__':
    init(0x27, 1)
    write(4, 0, 'Hello')
    write(7, 1, 'world!')

100

101

#!/usr/bin/env python3

import time

import smbus2 as smbus

BUS = smbus.SMBus(1)

def write_word(addr, data):

global BLEN

temp = data

if BLEN == 1:

temp |= 0x08

else:

temp &= 0xF7

BUS.write_byte(addr ,temp)

def send_command(comm):

# Send bit7-4 firstly

buf = comm & 0xF0

buf |= 0x04 # RS = 0, RW = 0, EN = 1

write_word(LCD_ADDR ,buf)

time.sleep(0.002)

buf &= 0xFB # Make EN = 0

write_word(LCD_ADDR ,buf)

# Send bit3-0 secondly

buf = (comm & 0x0F) << 4

buf |= 0x04 # RS = 0, RW = 0, EN = 1

write_word(LCD_ADDR ,buf)

time.sleep(0.002)

buf &= 0xFB # Make EN = 0

write_word(LCD_ADDR ,buf)

def send_data(data):

# Send bit7-4 firstly

buf = data & 0xF0

buf |= 0x05 # RS = 1, RW = 0, EN = 1

write_word(LCD_ADDR ,buf)

time.sleep(0.002)

buf &= 0xFB # Make EN = 0

write_word(LCD_ADDR ,buf)

# Send bit3-0 secondly

buf = (data & 0x0F) << 4

buf |= 0x05 # RS = 1, RW = 0, EN = 1

write_word(LCD_ADDR ,buf)

time.sleep(0.002)

buf &= 0xFB # Make EN = 0

write_word(LCD_ADDR ,buf)

def init(addr, bl):

# global BUS

# BUS = smbus.SMBus(1)

global LCD_ADDR

global BLEN

LCD_ADDR = addr

BLEN = bl

try:

send_command(0x33) # Must initialize to 8-line mode at first

time.sleep(0.005)

send_command(0x32) # Then initialize to 4-line mode

time.sleep(0.005)

send_command(0x28) # 2 Lines & 5*7 dots

time.sleep(0.005)

send_command(0x0C) # Enable display without cursor

time.sleep(0.005)

send_command(0x01) # Clear Screen

BUS.write_byte(LCD_ADDR, 0x08)

except:

return False

else:

return True

def clear():

send_command(0x01) # Clear Screen

def openlight(): # Enable the backlight

BUS.write_byte(0x27,0x08)

BUS.close()

def write(x, y, str):

if x < 0:

x = 0

if x > 15:

x = 15

if y <0:

y = 0

if y > 1:

y = 1

# Move cursor

addr = 0x80 + 0x40 * y + x

send_command(addr)

for chr in str:

send_data(ord(chr))

if __name__ == '__main__':

init(0x27, 1)

write(4, 0, 'Hello')

write(7, 1, 'world!')

Arduino, Tutorial

Arduino Tutorial 51: DHT11 Temperature and Humidity Sensor with LCD Display

March 3, 2020 admin

This shows our completed build with an Arduino Nano, LCD and DHT11 Sensor

In this lesson we work towards a stand alone Temperature and Humidity project using the DHT11 sensor.

This video will take you through the build and coding step-by-step, and the schematics below will help you follow along at home.

Our goal in this lesson is to add an LCD to the project. In lesson 50, we got the sensor working, and here we want to get the LCD connected. We are working with components from the Elegoo kit, which you can get HERE. In addition, your build can be much neater, cleaner and more stable is you use an arduino nano, instead of the standard arduino uno. The nano is small, and has male pins that allow it to be plugged directly into the breadboard, as seen above. I strongly suggest picking up an Arduino Nano, which you can get HERE. This lesson follows on to the work done in lesson 50. To recap, the DHT11 is connected as follows:

Connection schematic for the DHT11 Temperature Sensor.

You will also need to add the LCD, using the following schematic:

This schematic will allow you to connect the LCD to the

In my photograph at the top of the post, you can see it is important to keep the build neat, as there are lots of connections which must be made. Neat work is facilitated is you use short jumper wires, instead of the big male to male wires. You can get a jumper wire set that will keep your work neat HERE. I am not trying to sell you a bunch of junk, but as projects get more complicated, you really need to use the short straight wires, or your build will become a rat’s nest.

We develop the code in the video in detail, but you can get the finished code down below.

#include "DHT.h"
#define Type DHT11
#include <LiquidCrystal.h>
int rs=7;
int en=8;
int d4=9;
int d5=10;
int d6=11;
int d7=12;
LiquidCrystal lcd(rs,en,d4,d5,d6,d7);

int sensePin=2;
DHT HT(sensePin,Type);
float humidity;
float tempC;
float tempF;
int setTime=500;
int dt=1000;

void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
HT.begin();
delay(setTime);
lcd.begin(16,2);

}

void loop() {
humidity=HT.readHumidity();
tempC=HT.readTemperature();
tempF=HT.readTemperature(true);

lcd.setCursor(0,0);
lcd.print("Temp F= ");
lcd.print(tempF);
lcd.setCursor(0,1);
lcd.print("Humidity= ");
lcd.print(humidity);
lcd.print(" %");
delay(500);
lcd.clear();

Serial.print("Humidity: ");
Serial.print(humidity);
Serial.print("% Temperature ");
Serial.print(tempC);
Serial.print(" C ");
Serial.print(tempF);
Serial.println(" F ");

}

#include "DHT.h"

#define Type DHT11

#include <LiquidCrystal.h>

int rs=7;

int en=8;

int d4=9;

int d5=10;

int d6=11;

int d7=12;

LiquidCrystal lcd(rs,en,d4,d5,d6,d7);

int sensePin=2;

DHT HT(sensePin,Type);

float humidity;

float tempC;

float tempF;

int setTime=500;

int dt=1000;

void setup() {

// put your setup code here, to run once:

Serial.begin(9600);

HT.begin();

delay(setTime);

lcd.begin(16,2);

}

void loop() {

humidity=HT.readHumidity();

tempC=HT.readTemperature();

tempF=HT.readTemperature(true);

lcd.setCursor(0,0);

lcd.print("Temp F= ");

lcd.print(tempF);

lcd.setCursor(0,1);

lcd.print("Humidity= ");

lcd.print(humidity);

lcd.print(" %");

delay(500);

lcd.clear();

Serial.print("Humidity: ");

Serial.print(humidity);

Serial.print("% Temperature ");

Serial.print(tempC);

Serial.print(" C ");

Serial.print(tempF);

Serial.println(" F ");

}

Technology Tutorials

Tag Archives: LCD

Raspberry Pi LESSON 37: Raspberry Pi Security System

Raspberry Pi LESSON 36: Motion Detection Alarm System With LCD and Keypad

Creating a programmable Temperature Alarm with the Raspberry Pi

Library for I2C Connection of the LCD1602 to the Raspberry PI

Arduino Tutorial 51: DHT11 Temperature and Humidity Sensor with LCD Display

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