Raspberry Pi Pico | Technology Tutorials

In this video lesson we show how to create a simple project where the Raspberry Pi Pico W is connected to a DHT11 temperature and humidity sensor. The Pico measures the temperature and humidity from the sensor, and then displays it both on the Computer Screen, and on the LCD display we have connected to the Pico. The display toggles between showing degrees C and degrees F via a pushbutton. The schematic for the circuit is shown below:

Raspberry Pi Pico with DHT11 — Schematic showing how to connect LCD, pushbutton and DHT11 to the Raspberry Pi Pico W

Below is the software we developed for this project. Note you must first install the LCD library, which we show how to do HERE.

from machine import Pin
import utime as time
from dht import DHT11
from lcd1602 import LCD
lcd=LCD()

dataPin=16
myPin=Pin(dataPin,Pin.OUT,Pin.PULL_DOWN)
sensor=DHT11(myPin)

butPin=15
myButton=Pin(butPin,Pin.IN,Pin.PULL_UP)
tempUnitC=True
buttonState=1
buttonStateOld=1
print('My Sensor Data')
while True:
    buttonState=myButton.value()
    if buttonStateOld==0 and buttonState==1:
        tempUnitC= not tempUnitC
    try:
        sensor.measure()
    except:
        pass
    tempC=sensor.temperature()
    tempF=tempC*9/5+32
    hum=sensor.humidity()
    if tempUnitC==True:
        print("\r",'Temp= ',tempC,chr(176)+'C ', 'Humidity= ',hum,'%',end='    ')
        lcd.write(0,0,'Temp: '+str(tempC)+'\xDF'+'C  ')
        lcd.write(0,1,"Humidity: "+str(hum)+'%')
    if tempUnitC==False:
        print("\r",'Temp= ',tempF,chr(176)+'F ', 'Humidity= ',hum,'%',end='    ')
        lcd.write(0,0,'Temp: '+str(tempF)+'\xDF'+'F')
        lcd.write(0,1,"Humidity: "+str(hum)+'%')
    time.sleep(.1)
    buttonStateOld=buttonState

from machine import Pin

import utime as time

from dht import DHT11

from lcd1602 import LCD

lcd=LCD()

dataPin=16

myPin=Pin(dataPin,Pin.OUT,Pin.PULL_DOWN)

sensor=DHT11(myPin)

butPin=15

myButton=Pin(butPin,Pin.IN,Pin.PULL_UP)

tempUnitC=True

buttonState=1

buttonStateOld=1

print('My Sensor Data')

while True:

buttonState=myButton.value()

if buttonStateOld==0 and buttonState==1:

tempUnitC= not tempUnitC

try:

sensor.measure()

except:

pass

tempC=sensor.temperature()

tempF=tempC*9/5+32

hum=sensor.humidity()

if tempUnitC==True:

print("\r",'Temp= ',tempC,chr(176)+'C ', 'Humidity= ',hum,'%',end=' ')

lcd.write(0,0,'Temp: '+str(tempC)+'\xDF'+'C ')

lcd.write(0,1,"Humidity: "+str(hum)+'%')

if tempUnitC==False:

print("\r",'Temp= ',tempF,chr(176)+'F ', 'Humidity= ',hum,'%',end=' ')

lcd.write(0,0,'Temp: '+str(tempF)+'\xDF'+'F')

lcd.write(0,1,"Humidity: "+str(hum)+'%')

time.sleep(.1)

buttonStateOld=buttonState

This is some demonstration sample code showing use of the LCD1602 as an LCD display for the Raspberry Pi Pico W. The code is explained in the video above. It will prompt a user for his name, and then display a greeting on the LCD.

from lcd1602 import LCD
import utime as time
lcd=LCD()
while True:
    
    myName=input('What is Your Name? ')
    lcd.clear()
    greeting1='Hello '+myName
    greeting2='Welcome to My Pi'
    lcd.write(0,0,greeting1)
    lcd.write(0,1,greeting2)

from lcd1602 import LCD

import utime as time

lcd=LCD()

while True:

myName=input('What is Your Name? ')

lcd.clear()

greeting1='Hello '+myName

greeting2='Welcome to My Pi'

lcd.write(0,0,greeting1)

lcd.write(0,1,greeting2)

Below is the library for the Sunfounder Kepler Kit LCD1602 display. It allows the LCD display to operate with the Raspberry Pi Pico W. The code should be copied and pasted into Thonny, and then saved to your Raspberry Pi Pico W, to the same folder that contains you Python code. It MUST be saved with file name lcd1602.py

import machine
import time

class LCD():
    def __init__(self, addr=None, blen=1):
        sda = machine.Pin(6)
        scl = machine.Pin(7)
        self.bus = machine.I2C(1,sda=sda, scl=scl, freq=400000)
        #print(self.bus.scan())
        self.addr = self.scanAddress(addr)
        self.blen = blen
        self.send_command(0x33) # Must initialize to 8-line mode at first
        time.sleep(0.005)
        self.send_command(0x32) # Then initialize to 4-line mode
        time.sleep(0.005)
        self.send_command(0x28) # 2 Lines & 5*7 dots
        time.sleep(0.005)
        self.send_command(0x0C) # Enable display without cursor
        time.sleep(0.005)
        self.send_command(0x01) # Clear Screen
        self.bus.writeto(self.addr, bytearray([0x08]))

    def scanAddress(self, addr):
        devices = self.bus.scan()
        if len(devices) == 0:
            raise Exception("No LCD found")
        if addr is not None:
            if addr in devices:
                return addr
            else:
                raise Exception(f"LCD at 0x{addr:2X} not found")
        elif 0x27 in devices:
            return 0x27
        elif 0x3F in devices:
            return 0x3F
        else:
            raise Exception("No LCD found")

    def write_word(self, data):
        temp = data
        if self.blen == 1:
            temp |= 0x08
        else:
            temp &= 0xF7
        self.bus.writeto(self.addr, bytearray([temp]))
    
    def send_command(self, cmd):
        # Send bit7-4 firstly
        buf = cmd & 0xF0
        buf |= 0x04               # RS = 0, RW = 0, EN = 1
        self.write_word(buf)
        time.sleep(0.002)
        buf &= 0xFB               # Make EN = 0
        self.write_word(buf)

        # Send bit3-0 secondly
        buf = (cmd & 0x0F) << 4
        buf |= 0x04               # RS = 0, RW = 0, EN = 1
        self.write_word(buf)
        time.sleep(0.002)
        buf &= 0xFB               # Make EN = 0
        self.write_word(buf)
    
    def send_data(self, data):
        # Send bit7-4 firstly
        buf = data & 0xF0
        buf |= 0x05               # RS = 1, RW = 0, EN = 1
        self.write_word(buf)
        time.sleep(0.002)
        buf &= 0xFB               # Make EN = 0
        self.write_word(buf)

        # Send bit3-0 secondly
        buf = (data & 0x0F) << 4
        buf |= 0x05               # RS = 1, RW = 0, EN = 1
        self.write_word(buf)
        time.sleep(0.002)
        buf &= 0xFB               # Make EN = 0
        self.write_word(buf)
    
    def clear(self):
        self.send_command(0x01) # Clear Screen
        
    def openlight(self):  # Enable the backlight
        self.bus.writeto(self.addr,bytearray([0x08]))
        # self.bus.close()
    
    def write(self, 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
        self.send_command(addr)

        for chr in str:
            self.send_data(ord(chr))
    
    def message(self, text):
        #print("message: %s"%text)
        for char in text:
            if char == '\n':
                self.send_command(0xC0) # next line
            else:
                self.send_data(ord(char))

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import machine

import time

class LCD():

def __init__(self, addr=None, blen=1):

sda = machine.Pin(6)

scl = machine.Pin(7)

self.bus = machine.I2C(1,sda=sda, scl=scl, freq=400000)

#print(self.bus.scan())

self.addr = self.scanAddress(addr)

self.blen = blen

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

time.sleep(0.005)

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

time.sleep(0.005)

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

time.sleep(0.005)

self.send_command(0x0C) # Enable display without cursor

time.sleep(0.005)

self.send_command(0x01) # Clear Screen

self.bus.writeto(self.addr, bytearray([0x08]))

def scanAddress(self, addr):

devices = self.bus.scan()

if len(devices) == 0:

raise Exception("No LCD found")

if addr is not None:

if addr in devices:

return addr

else:

raise Exception(f"LCD at 0x{addr:2X} not found")

elif 0x27 in devices:

return 0x27

elif 0x3F in devices:

return 0x3F

else:

raise Exception("No LCD found")

def write_word(self, data):

temp = data

if self.blen == 1:

temp |= 0x08

else:

temp &= 0xF7

self.bus.writeto(self.addr, bytearray([temp]))

def send_command(self, cmd):

# Send bit7-4 firstly

buf = cmd & 0xF0

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

self.write_word(buf)

time.sleep(0.002)

buf &= 0xFB # Make EN = 0

self.write_word(buf)

# Send bit3-0 secondly

buf = (cmd & 0x0F) << 4

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

self.write_word(buf)

time.sleep(0.002)

buf &= 0xFB # Make EN = 0

self.write_word(buf)

def send_data(self, data):

# Send bit7-4 firstly

buf = data & 0xF0

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

self.write_word(buf)

time.sleep(0.002)

buf &= 0xFB # Make EN = 0

self.write_word(buf)

# Send bit3-0 secondly

buf = (data & 0x0F) << 4

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

self.write_word(buf)

time.sleep(0.002)

buf &= 0xFB # Make EN = 0

self.write_word(buf)

def clear(self):

self.send_command(0x01) # Clear Screen

def openlight(self): # Enable the backlight

self.bus.writeto(self.addr,bytearray([0x08]))

# self.bus.close()

def write(self, 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

self.send_command(addr)

for chr in str:

self.send_data(ord(chr))

def message(self, text):

#print("message: %s"%text)

for char in text:

if char == '\n':

self.send_command(0xC0) # next line

else:

self.send_data(ord(char))

Technology Tutorials

Category Archives: Raspberry Pi Pico

Measure Temperature and Humidity on the Raspberry Pi Pico W

LCD1602 Display Library for Micropython and the Raspberry Pi Pico W

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