Tag Archives: DHT11

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

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.

temperature sensor — This schematic shows how to create a programmable temperature alarm

3D Graphics with Visual Python, Arduino, Arduino with Python, Python

Using an Arduino with Python LESSON 8: Live Thermometer 3D Visual Using DHT11

March 1, 2022 admin

In this video lesson we connect the Arduino to a DHT11 temperature and humidity sensor. We show how to wire the device up, and then how to code the Arduino. The data is passed from the Arduino to python. We then create a live 3D thermometer model that updates as the temperature changes.

On the arduino side, this is the code which we use:

#include "DHT.h"
#define DHTPIN 2
#define DHTTYPE DHT11

float tempF;
float tempC;
float humidity;

int setTime=500;
int dt=1000;

DHT TH(DHTPIN,DHTTYPE);

void setup() {
  // put your setup code here, to run once:
Serial.begin(115200);
TH.begin();
delay(setTime);
}
void loop() {
  // put your main code here, to run repeatedly:
tempC=TH.readTemperature();
tempF=TH.readTemperature(true);
humidity=TH.readHumidity();


Serial.print(tempF);
Serial.print(",");
Serial.println(humidity);

delay(dt);
}

#include "DHT.h"

#define DHTPIN 2

#define DHTTYPE DHT11

float tempF;

float tempC;

float humidity;

int setTime=500;

int dt=1000;

DHT TH(DHTPIN,DHTTYPE);

void setup() {

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

Serial.begin(115200);

TH.begin();

delay(setTime);

}

void loop() {

// put your main code here, to run repeatedly:

tempC=TH.readTemperature();

tempF=TH.readTemperature(true);

humidity=TH.readHumidity();

Serial.print(tempF);

Serial.print(",");

Serial.println(humidity);

delay(dt);

}

Then on the python side, we use the following code:

import time
import serial
from vpython import *

arduinoData=serial.Serial('com3',115200)
time.sleep(.5)
digValue=label(text='50',height=20,box=False,pos=vector(0,-2.5,2))
bulb=sphere(radius=1,color=color.red,pos=vector(0,-3,0))
cyl=cylinder(radius=.6,color=color.red,axis=vector(0,1,0),length=6,pos=vector(0,-3,0))
bulbGlass=sphere(radius=1.2,color=color.white,opacity=.25,pos=vector(0,-3,0))
cylGlass=cylinder(radius=.8,color=color.white,axis=vector(0,1,0),opacity=.25,length=6,pos=vector(0,-3,0))
for temp in range(0,115,10):
    tickPos=4.5/115*temp+1.5
    tick=cylinder(radius=.7,color=color.black,length=.1,axis=vector(0,1,0),pos=vector(0,tickPos-3,0))
    label=text(text=str(temp),color=color.white,pos=vector(-2,tickPos-3,0),height=.3)
while True:
    while arduinoData.in_waiting==0:
        pass
    dataPacket=arduinoData.readline()
    dataPacket=str(dataPacket,'utf-8')
    dataPacket=dataPacket.strip('\r\n')
    dataPacket=dataPacket.split(',')
    temp=float(dataPacket[0])
    hum=float(dataPacket[1])
    len=(4.5/115)*temp+1.5
    cyl.length=len
    digValue.text=str(temp)

import time

import serial

from vpython import *

arduinoData=serial.Serial('com3',115200)

time.sleep(.5)

digValue=label(text='50',height=20,box=False,pos=vector(0,-2.5,2))

bulb=sphere(radius=1,color=color.red,pos=vector(0,-3,0))

cyl=cylinder(radius=.6,color=color.red,axis=vector(0,1,0),length=6,pos=vector(0,-3,0))

bulbGlass=sphere(radius=1.2,color=color.white,opacity=.25,pos=vector(0,-3,0))

cylGlass=cylinder(radius=.8,color=color.white,axis=vector(0,1,0),opacity=.25,length=6,pos=vector(0,-3,0))

for temp in range(0,115,10):

tickPos=4.5/115*temp+1.5

tick=cylinder(radius=.7,color=color.black,length=.1,axis=vector(0,1,0),pos=vector(0,tickPos-3,0))

label=text(text=str(temp),color=color.white,pos=vector(-2,tickPos-3,0),height=.3)

while True:

while arduinoData.in_waiting==0:

pass

dataPacket=arduinoData.readline()

dataPacket=str(dataPacket,'utf-8')

dataPacket=dataPacket.strip('\r\n')

dataPacket=dataPacket.split(',')

temp=float(dataPacket[0])

hum=float(dataPacket[1])

len=(4.5/115)*temp+1.5

cyl.length=len

digValue.text=str(temp)

Arduino, Tutorial

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

March 3, 2020 admin

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:

DHT11 Sensor — Connection schematic for the DHT11 Temperature Sensor.

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

Arduino LCD 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 ");

}

Arduino, Tutorial

Arduino Tutorial 50: How to Connect and Use the DHT11 Temperature and Humidity Sensor

February 25, 2020 admin

In this lesson we show how to measure Temperature and Humidityusing the DHT11 sensor. This is a relatively simple sensor to use, but you will have to download and install a library. In our earlier lessons, we have used libraries before, but this is the first time you will have to download a library. The library I used was downloaded from HERE. The video explains in detail how to install the library, but in a nutshell you download the library from clicking the link on that page. Then you need to open the downloaded zip file, and then drag and drop the contents of the zip file to your desktop. Next you must determine where your arduino library folder is. You can do that by going to the arduino IDE, and under “file” select preferences. This will show you your “Sketchbook Location”, and that folder will contain your libraries folder. The folder you dragged and dropped onto your desktop should be dragged and dropped now into this library folder. The video shows you how to do this if this description is not clear. Now you will need to connect the sensor, according to this schematic:

The video develops the code to use this sensor step-by-step, but the code is included below for your convenience.

#include "DHT.h"
#define Type DHT11
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);
}

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

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


}

#include "DHT.h"

#define Type DHT11

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);

}

void loop() {

humidity=HT.readHumidity();

tempC=HT.readTemperature();

tempF=HT.readTemperature(true);

Serial.print("Humidity: ");

Serial.print(humidity);

Serial.print("% Temperature ");

Serial.print(tempC);

Serial.print(" C ");

Serial.print(tempF);

Serial.println(" F ");

delay(dt);

}

Technology Tutorials

Tag Archives: DHT11

Measure Temperature and Humidity on the Raspberry Pi Pico W

Creating a programmable Temperature Alarm with the Raspberry Pi

Using an Arduino with Python LESSON 8: Live Thermometer 3D Visual Using DHT11

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

Arduino Tutorial 50: How to Connect and Use the DHT11 Temperature and Humidity Sensor

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