arduino dht11 lcd display quotation

I downloaded a bookstore that worked on my arduino mega 2560, but I can only read the sensor data on the serial monitor of the arduino software. Would you like to modify the code to throw that data on the display? I tried to, but until now I could not.

Since my study was not always at the best temperature, I decided it would be useful to display the ambient temperature on my desk. The cost of a sensor that provided humidity, in addition to temperature, was not prohibitive; therefore that was what was chosen.

Both the DHT11 and DHT22 sensors I considered provide temperature results in Centigrade. Fortunately it is an easy conversion to Fahrenheit (the format used in the USA, which is my location) . The sketch below displays temperature in both Fahrenheit and Centigrade, so it is applicable to whatever region of the world you are located in.

There are many published examples on-line showing how to display humidity and temperature using an Arduino UNO, some include displaying the results on an LCD. In this Instructable, we will also display the results on an LCD, but with the addition of power conservation that allows the LCD backlight to be toggled on and off when the display is not needed. This ability was meaningful to me, as I prefer to be able to turn the display off when I am not in the study.

If you are using a “wall wart” extra power consumption may not be of overwhelming importance, but if you are powering the display from a battery it likely is, as reduced power consumption will extend a battery’s life.

I considered both the DHT22 and the DTH11/12 sensors, and settled on the DHT22, although slightly more expensive. The DHT11 can often be purchased for less than $2, while the DHT22 is often found for less than $5. If purchased directly from China, the cost can be even less. If I only wanted to display temperature, I could have used instead the TMP36 sensor and realized some savings, and indeed this is how I built an earlier DIY of mine. However, I decided to include a humidity display in this project.

The DHT22 is slightly more accurate than the DHT11. So, the slightly higher cost of the DHT22 seemed reasonable. Both DTH devices contain capacitive humidity sensors. These humidity sensors are widely used for industrial and commercial projects. While not extremely accurate, they are capable of functioning at relatively high temperatures and have a reasonable resistance to chemicals in their surroundings. They measure the changes in a dielectric that are produced by the relative humidity of their surroundings. Fortunately, the changes in capacitance are essentially linear in relation to humidity. The relative accuracy of these sensors can be easily seen by placing two of them side-by-side. If this is done it will be seen that they differ by, at most, 1 or 2 percentage points.

The DHT11/22 sensors can easily be substituted for each other. Depending on cost constraints, if any, either sensor can be chosen. They both come in similar 4-pin packages that are interchangeable, and as we will see shortly only 3 of the 4 pins on either package will be needed to build the desktop humidity and temperature display presented here. Although only three pins are needed for use, the four pins provide additional stability when these DHT sensors are placed/mounted on a breadboard.

In this project you’ll create a standalone web server with an ESP8266 that displays the temperature and humidity with a DHT11 or DHT22 sensor using the Arduino IDE. The web server you’ll build can be accessed with any device that has a browser on your local network.

Before proceeding with the tutorial, wire the DHT11 or DHT22 temperature and humidity sensor to the ESP8266 as shown in the following schematic diagram.

We’ll program the ESP8266 using Arduino IDE, so you must have the ESP8266 add-on installed in your Arduino IDE. If you haven’t, follow the next tutorial first:

As you can see in the above figure, the web page shows one heading and two paragraphs. There is a paragraph to display the temperature and another to display the humidity. There are also two icons to style the page.

In this section, we’ll show you how to build a simple HTTP web server that displays the temperature and humidity in a raw HTML page. This web server sends an HTTP response when your browser makes a request on the ESP8266 IP address.

We’ll program the ESP8266 using Arduino IDE, so you must have the ESP8266 add-on installed in your Arduino IDE. If you haven’t follow the next tutorial first.

In this project we’ve shown you how to display sensor readings from a DHT sensor on a web page. We’ve provided two examples: a simple web server and an asynchronous web server with auto-updates.

Now, you can easily modify the examples provided to display readings from other sensors. If you like the ESP8266 and IoT projects take a look at some of our resources:

Using a display to view the temperature and humidity of your environment can be possible using the DHT11 or DHT22 sensor with the easy to use Arduino microcontroller platform and that’s the goal of this project. For this project, we will be using the 16×2 LCD display module to display the temperature and humidity readings gathered from the environment using the DHT11 temperature and humidity sensor.

Although the DHT11 temperature and humidity sensor isn’t the fastest temperature and humidity sensor around, it has fair level of accuracy, +-5% for humidity readings and +-2% for temperature readings. With the DHT we will be able to measure temperature and humidity of the environment with a very fair degree of accuracy.

The LCD Keypad shield makes connecting the 16×2 LCD module to any system quite easy as it simply just plugs on the Arduino mega which is being used for this project.

Putting the component together is very easy if using the LCD keypad shield. All you just need to do is plug the LCD in as shown below and connect the DHT as described in the schematics above.

Note that the RW pin is connected to GND because we will be writing only to the LCD and not to read from it, for this to be possible the RW pin has to be pulled LOW

Pin connection of the dht11 to the arduino is as illustrated below. All DHT11 sensors have three main functional pins. The DHT types with four pins always have a void pin which is never connected to anything.

Before we start, we have to download DHT library and set its type. The required library is available on github. Download it and extract it into Arduino libraries folder, then open Arduino IDE. Its probably important to note at this point that the library will not be visible to an Arduino IDE instance that was already running before installation, you have to restart the Arduino IDE after installing the library.

With the next line, we create an LCD object,  passing in the Arduino pin numbers to which our LCD pins are connected as follows in the format lcd (RS, E, D4, D5, D6, D7).

In the setup function, we call the LCD begin method, passing in the LCD size which is a 16×2. Next, we print a message to indicate the device has commenced reading data from the sensor on the first line of the LCD then call the DHT begin method.

Moving on to the loop() function, we create two variables of type float which will hold the temperature and humidity value, give it a delay of two seconds after reading values into them and then clear the LCD.

Next we create two character arrays both of size six and then we use the dtostrf function to convert our temperature and humidity value from type float to string and then we print it on the LCD. Note that the explicit typecasting used in the lcd.print() function ((char)223) is used to print the degree symbol on the display.

Save your code, connect your Mega to your computer and make sure under your tools menu, the board picked is “Arduino/Genuino Mega or Mega 2560” and also ensure the right COM port is selected. Click upload when done and you should have something like the Image below.

The DHT11 temperature and humidity sensor is a nice little sensor that provides digital temperature and humidity readings. It’s really easy to set up, and only requires one wire for the data signal. These sensors are popular for use in remote weather stations, soil monitors, and home automation systems.

Programming the DHT11 and connecting it to a Raspberry Pi is pretty simple too. In this tutorial, I’ll show you how to connect the DHT11 to the Raspberry Pi and output the humidity and temperature readings to an SSH terminal or to an LCD. Then I’ll give you some example programs for programming it with either C or Python.

We have another tutorial on the DHT11 for the Arduino that goes into detail on relative humidity and how the DHT11 measures it. So instead of repeating all of that here, check out How to Set Up the DHT11 Humidity Sensor on an Arduino, then come back for the specifics on setting it up on the Raspberry Pi.

But just to quickly summarize… The DHT11 has a surface mounted NTC thermistor and a resistive humidity sensor. An IC on the back of the module converts the resistance measurements from the thermistor and humidity sensor into digital temperature (in °C) and relative humidity measurements.

There are two variants of the DHT11 you’re likely to come across. One is a three pin PCB mounted module and the other is a four pin stand-alone module. The pinout is different for each one, so connect the DHT11 according to which one you have:

I’ll explain how to use both C and Python to get temperature and humidity from the DHT11, so you’ll be able to incorporate the DHT11 into pretty much any existing RPi project.

We’ll be using WiringPi to program the DHT11 in C. If you don’t have WiringPi installed already, follow this link for instructions on how to install WiringPi.

For temperature in Celsius, un-comment line 72 where it says lcdPrintf(lcd, "Temp: %d.0 C", dht11_dat[2]);, then comment out line 73. To find out more about how to control text on an LCD with C, check out How to Setup an LCD on the Raspberry Pi and Program it With C.

We’ll be using the Adafruit DHT11 Python library. You can download the library using Git, so if you don’t have Git installed on your Pi already, enter this at the command prompt:

To output the DHT11 readings to an LCD, we’ll need to install another Python library called RPLCD to drive the LCD. To install the RPLCD library, we first need to install the Python Package Index, or PIP. PIP might already be installed on your Pi, but if not, enter this at the command prompt to install it:

That should about cover most of what you’ll need to get the DHT11 up and running on your Raspberry Pi. Hope this made it easier for you. Be sure to subscribe if you liked this article and found it useful, and if you have any questions or need help with anything, just leave a comment below…

Let"s get started with this innovative Arduino tutorial where you will learn about the DHT11 Temperature and Humidity Sensor Module and how to use it with our Arduino Board to create our own weather station project at home.

The DHT11 module is a temperature and humidity sensing module that uses Digital Signal Acquisition to translate temperature and humidity to a digital reading that a microcontroller can easily read. The DHT11 has a temperature range of 0°C to 50°C, which is ideal for home or hobby use.

The DHT11 Humidity and Temperature Sensor is made up of three main parts. A resistive type humidity sensor, an NTC thermistor (to calculate temperature), and an 8-bit microcontroller that transforms the analog signals from both sensors into a single digital signal.

The DHT11 Sensor can detect humidity levels ranging from 20% to 90% relative humidity (RH) and temperatures ranging from 0 to 50°C. The sensor"s sampling time is one second.

Initially Arduino sends a high to low start signal to DHT11 with 18µs delay to ensure DHT’s detection. The Arduino then pulls up the data line and waits 20-40µs for DHT to respond. When DHT detects a start signal, it sends a low voltage level response signal to the Arduino with an 80µs delay. The DHT controller then pulls up the data line and holds it for 80µs for DHT’s arrangement of sending data.

When the data bus voltage is low, the DHT11 is sending a response signal. After that, DHT performs another data line pull-up for 80µs to prepare data transmission.

Data format that is sent by DHT to the Arduino for every bit starts with 50µs low voltage level and length of high voltage level signal decides whether data bit is0or1.

LCD modules are a critical component in many Arduino-based embedded systems. As a result, understanding how to attach an LCD module to an Arduino is crucial when designing embedded systems. Here you will learn how to connect an Arduino to a 16x2 LCD display.

The JHD162A is a 16x2 LCD module based on Hitachi"s HD44780 driver. The JHD162A has 16 pins and can be used in 4-bit or 8-bit mode (using only four data lines) or (using all 8 data lines) respectively. In this case, the LCD module is set to 4-bit mode.

Pin4(RS): Register select pin.The JHD162A has two registers namely command register and data register. Logic HIGH at RS pin selects data register and logic LOW at RS pin selects command register. If we make the RS pin HIGH and feed an input to the data lines (DB0 to DB7), this input will be treated as data to display on the LCD screen. If we make the RS pin LOW and feed an input to the data lines, then this will be treated as a command ( a command to be written to LCD controller – like positioning cursor or clear screen or scroll).

Pin15(Backlight +): Anode of the back light LED. When operated on 5V, a 560 ohm resistor should be connected in series to this pin. In arduino based projects the back light LED can be powered from the 3.3V source on the arduino board.

LCD module enable pin to the Arduino"s digital pin 11. The LCD module and the Arduino are connected in 4-bit mode in this project. This means that only four of the LCD"s digital input lines (DB4 to DB7) are used.

This method is very simple and needs fewer connections, and allows you to almost fully leverage the LCD module"s capabilities. The digital lines DB4, DB5, DB6, and DB7 are connected to the Arduino"s digital pins 5, 4, 3, and 2. The 10K potentiometer is used for controlling the contrast of the light. The current through the back light LED is limited by the 560 ohm resistor R1.

A built-in library in Arduino called LiquidCrystal.h> to enable communication between the Arduino and the LCD module is used here. This library is written for LCD modules that use the Hitachi HD44780 chipset (or a compatible chipset). This library can accommodate LCD wiring in both 4 bit and 8 bit modes.

LiquidCrystal lcd()– is  a constructor used to declare a variable of its kind. Here ‘lcd’ is the variable declared using the constructor and is used to call methods defined inside the library LiquidCrystal.h

We imported the DHT and LiquidCrystal libraries in the first two lines of this code. Then we created a variable DPIN to hold the PIN to which the DHT11 data pin is attached. Next, we created a new variable DTYPE, which contains the name of the sensor"s type (DHT11 or DHT22)

Similarly, rs, en, d4, d5, d6, and d7 are the pins of the LCD whose values are assigned to the number of the pins they are attached to respectively. To set up our LCD and sensor, we now use two functions called LCD and DHT.

The setup() function is then used to start our LCD display and DHT11 sensor. Since the setup() function only runs once after the project is powered on, the syntax in it starts the LCD and sensor at the beginning.

After that, we"ll look at the loop() feature. Since we need a time interval to display the results, we added a delay of 0.5 seconds or 5000 milliseconds. Following that, we declared two float variables, ‘h" and ‘t." The letters ‘h" and ‘t" represent the percentage value of humidity and the centigrade value of temperature, respectively.

The loop() function"s if statement tests if we"re getting both humidity and temperature; otherwise, the LCD will show "Failed to read from DHT sensor!" The following lines of code simply provide the syntax for printing our result on the LCD.

The DHT11 is a simple digital temperature/humidity sensor that easily connects to any Arduino. Most sample programs just take the reading and output it to the serial port. This example code will let you connect a LCD screen and track the min and max temp/humidity readings.

It doesn’t take much to put this all together. Place the SainSmart LCD Shield over the Arduino and connect the headers together. I then used 3 male to female breadboard wires to connect the sensor into the A5 (Analog 5) port. Then write/copy the software and you are ready to go.

After building this I have one complaint, is the data from the DHT11 even realistic. The temperature result is an easy one to check but the relative humidity can seem more like a predictable random number. In the project, you will see various fudge factors to align the DHT11 to a more realistic number. The question raises, does the DHT11 need a constant calibration factor or does it need varying amounts of correction at different temperatures and humidity.

The DHT11 has an accuracy of 1 degree in Celsius, which after conversion gives you about 2 degree accuracy in Fahrenheit. For most applications, it’s probably not a big deal, but it leaves you wanting more resolution. The reason for decimal points in the 9.0/5.0 (C to F conversion) is to force the compiler to treat 9/5 as a floating point [1.88] instead of an integer [1].

Here I am going to display the temperature and humidity using the DHT11 sensor and LCD display 1602 with an I2C module and a relevant code.Now I have been struggling with this project for like hours now. But at the end I find out I did not have the correct knowledge. So people it is very important to know what you are making. In this case I recommend you to go through the page and not just copy and paste the code.

Now, this project uses a DHT11 temperature and humidity sensor with the three pin but you can also use any other sensor the changes in the code should be as per the model. I have used Arduino UNO for this project.

This paper presents designing and implementing an Automatic room temperature control system using the Arduino and DHT11 sensor. The fan speed control system has also been proposed. Here, the user sets the minimum and the maximum reference temperature range from the keypad. The DHT11 sensor senses the surrounding room temperature and gives the result in degrees Celsius. Both the reference and the measured values are displayed on the Liquid Crystal Display (LCD). The Arduino microcontroller…Expand