arduino dht11 lcd display manufacturer

Want to keep a log of the climate in your greenhouse, build a humidor control system, or track temperature and humidity data for a weather station project? AOSONG’s DHT11 or DHT22 Temperature and Humidity Sensor could be the perfect fit for you!

These sensors are factory-calibrated and do not require any external components to function. With just a few connections and a bit of Arduino code, you can begin measuring relative humidity and temperature right away.

The DHT11 and the DHT22 are the two most widely used sensors in the DHTxx series. They look kind of the same and have the same pinout, but their specs are different.

Of the two, the DHT22 is more expensive and, undoubtedly, has better specifications. The DHT22 can measure temperatures from -40°C to +125°C with an accuracy of ±0.5°C, while the DHT11 can measure temperatures from 0°C to 50°C with an accuracy of ±2°C. In addition, the DHT22 sensor can measure relative humidity from 0 to 100% with an accuracy of 2-5%, while the DHT11 sensor can only measure relative humidity from 20 to 80% with an accuracy of 5%.

Despite the fact that the DHT22 is more accurate, precise, and capable of operating in a wider range of temperature and humidity, there are three areas where the DHT11 completely outperforms the DHT22 – It is more affordable, more compact, and has a higher sampling rate. DHT11 takes a reading once per second (or 1Hz sampling rate), while DHT22 takes a reading once every two seconds (or 0.5Hz sampling rate).

Despite these differences, the operating voltage of both sensors ranges from 3 to 5 volts, with a maximum current of 2.5mA (during conversion). The best part is that DHT11 and DHT22 sensors are swappable, which means that if you build your project with one, you can simply unplug it and replace it with another. Your code may need to be tweaked slightly, but the wiring remains the same!

Connecting DHT sensors to Arduino is straightforward. They have fairly long 0.1′′-pitch pins, allowing them to be easily plugged into any breadboard. Connect the VCC pin to the Arduino’s 5V and the GND pin to ground. Finally, connect the Data pin to digital pin #8.

After installing the library, copy and paste this sketch into the Arduino IDE. The following test sketch will print the temperature and relative humidity values to the serial monitor. Try out the sketch, and then we’ll go over it in more detail.

The sketch begins by including the DHT library. Following that, we specify the Arduino pin number to which our sensor’s Data pin is connected and create a DHT object.

In the loop, we use the read22(dataPin) function to read the DHT22. This function takes as a parameter the sensor’s Data pin number. When working with DHT11, you must use the read11() function; to do so, you just need to uncomment the second line.

If you’re constructing your own incubator or a similar project, you’ll need a 16×2 character LCD rather than a serial monitor to display the current temperature and humidity levels. So, in this example, we’ll also connect the LCD to the Arduino in addition to the DHT11 and DHT22 sensors.

The sketch below will display the temperature and relative humidity values on the 16×2 character LCD. This sketch is similar to the previous one, except that the values are printed on the LCD.

If you do not know about DHT11, DHT22 temperature sensor and LCD (pinout, how it works, how to program ...), learn about them in the following tutorials:

The above code also work for Arduino Nano. A grandfather, who learns through this tutorial to guide his grandchild has tested this code with Arduino Nano and send us the result like below:

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I have the dht11 reading and printing to lcd and serial monitor.I have the dht11 controlling two relays one for temp and one for humidity.When the relay turns on the dht11 stops sending readings and freezes and stops reading? Any way I can fix that ?thanks

The output is to the serial monitor, unless you have connected an LCD. The video will show you how to open the serial monitor if you don’t already know how to.

A quick question tho, do you have a tutorial on how to connect this to a wireless transceiver?? also in theory could i connect more then one humidity detector to an arduino in order to detect humidity from more then one spot? Thank you again and i’ve subscribed!

Hi Jose, you can definitely connect more than one sensor to a single Arduino. You would basically duplicate the code, and have a separate pins read the data from each sensor. As for connecting them to a wireless tranceiver, I’m sure it’s possible, but you would probably need to use another microcontroller as a hub to transmit the data. I haven’t tried it yet though, so don’t take my word for it!

Hello, I built my first arduino project (measuring the room temperature and humidity with the DHT11) during Christmas holidays. The readings of the values were shown on the screen of my laptop. The measured room temperature was correct, but the measured humidity was much too low (about 20%RH). What can be the reason for ithe low humidity? And how can the sensor (if needed) be recalibrated?

vcc is the left one, signal the middle one and ground is the round one, in case of a 3 pin DHT11. the diagram above is not right. i was getting the same problem here.

The diagram is correct for most three pin DHT11 modules. Depending on the manufacturer, the pins on the PCB might be different though. The pins should be labelled with S for signal and “-” or “GND” ground.

See the section “Output Humidity and Temperature Readings to an LCD Display” on a desktop… If you are viewing it on mobile, the full code might not display. Hope this helps

It sounds like you want to control the heater with the DHT11 and have the readings output to an LCD too… You can use the DHT11 to control the signal to a 5V relay, similar to what’s done in this article: https://www.circuitbasics.com/build-an-arduino-controlled-power-outlet/

Then you just need to add the code to initialize the LCD, include the LiquidCrystal library, and change the “serialprint()” functions to “lcd.print(). We have another article on setting up an LCD on the Arduino if you need help with it: https://www.circuitbasics.com/how-to-set-up-an-lcd-display-on-an-arduino/

i didnt have any trouble interfacing the arduino, lcd and the dht11 sensor and my codes were quite right since when i run it, nothing’s odd in the output. but when i connect the relay,in which an ac device is connected, as an output that turns on after a couple of minutes, the temperature and humidity dislayed on the lcd becomes odd, like chinese and numbers, after some time. i checked my codes but i cant figure out whats wrong with it.

please help me.. i won’t get Alarm temperature and humidity..and show in lcd display 16×2.. and changeing temperature, humidity alarm set point HOW IS DO… PLEASE HELP ME.

Any comments about DHTLib v0.1.14 vs. v0.1.21, and why this simple Arduino sketch works in the former, but not the latter? The brief history in the cpp file header for v0.1.21 looks like it took care of a few issues so my first instinct is to use that, but again, it results in all zero readings. Anyway, if no comments, well, I’ll have to take a look through the diffs between the two versions to see what might be causing the issue.

vcc is the left one, signal the middle one and ground is the right one, in case of a 3 pin DHT11. the diagram above is not right. i was getting the same problem here.

The diagram is correct, but your particular DHT11 could have a different pinout depending on the manufacturer. The DHT11 I used is from Keyes, what type do you have?

Are you using the four pin DHT11? If so you’ll need to put a 10K Ohm resistor between the Signal line and Vcc. I just added another diagram to the post to make it a bit clearer. That may be causing your issue.

Thanks a lot, may you please help me out, I am using a Mega 2560 with a DHT11 sensor, my problem is that both temperature and humidity reading is just being reed as 0.00 and they are not changing. What might i be doing wrongly, I have even tried the code that accompanies these tutorials

This seems like a really simple setup, but I’ve been having a lot of trouble setting this up. Have there been changes to this library? I have downloaded it, but arduino still refuses to recognize dht or any of the related functions, like temperature/humidity. It had a lot of trouble with line 3, dht DHT;. Any advice?

Hi, you mentioned you added a piece of code to show the “degree” symbol,” lcd.print((char)223)”, can you tell me if the number 223 is from the ASCII table.

vcc is the left one, signal the middle one and ground is the right one, in case of a 3 pin DHT11. the diagram above is not right. i was getting the same problem here.

i am doing fire alarm system using dht and lcd and GSM sim800l how can i make argument to send message from gsm if the sensor reading is higher that the set temp and how to declare it thanks for your response

I am very happy to inform you that I fixed successfully the temp and humidity project with LCD display. I would like to subscribe but cannot find the link.Many thanks

C:\Users\mhine\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.2.0\cores\esp8266/Arduino.h:227:63: error: cannot convert ‘volatile uint32_t* {aka volatile unsigned int*}’ to ‘volatile uint8_t* {aka volatile unsigned char*}’ in initialization

Hi. I have the same issue with the same board. Did you get it to succeed in the end? I would be interested, but I feel that it may be a compatibility issue with a 3rd-party board. I have tried the exact code with other Arduinos that I have and it works just fine.

I get this same error when I try to use the Arduino 101 instead of the Uno. I think the library doesn’t support the board. I would try finding a different DHT library, there are several others out there.

I Have issues with the Arduino recognizing the file dht.h. Was told no such file exist, meanwhile I have uploaded the zip file into the Arduino IDE, which showed in the file directory.

Did you use the library in the zip file from the post, or did you download it from the Arduino.cc page? Version 0.1.21 has some issues and doesn’t appear to work. The zip file in the post is version 0.1.14, and it does work. Also, are you using the Uno, or another board? I couldn’t get the library to work on my Arduino 101…

In this language, does declaring an object variable (as in “dht DHT;”) automatically instantiate it? I am more used to other languages that would need to follow the declaration with something along the lines of “DHT = new dht(params, for, constructor);” Does this normally go without saying in C++, or is this something the Arduino environment automatically adds at the preprocessing** stage?

**: If not “preprocessing,” then whatever else Arduino parlance calls the process of converting/expanding the “Processing” (??) or “Wiring” (???) code into standard C/C++ ????

hey can you pls help me how to use rf module with the above project. i am using two arduino uno, DHT11, LCD, RF transmitter and receiver. please can u give me a code to display temperature and humidity on the receiver side lcd…

I connected the LCD and the DHT11 and copied and pasted the code. It uploaded and then I look at my LCD and all I see are white boxes on the top of the display. Can anyone help me?

I copied this exactly and got it to display temperature and humidity, but it flashes -999 for temp and -999 for humidity every other second. For example, it will display correct readings for one second, then the -999 for both readings the next second.. Flashing between the two. Any ideas why it might be doing this. I have been playing with the code, rechecking pins, etc, but I cant seem to pinpoint the problem. Any input is appreciated.

hello, i need some help, i want code for, if i m sending message from mobile (e.g. ABC) to arduino via gsm module then the values of temperature and humidity receiving specific number

I have arn Arduino y module that I am using to trgger an extractor fan in a shower. I was wondering whether this humidity sensor could be used to simply close the 5v circuit so teh fan runs on until teh humidity is below a set vaue. Is that possible simply?

Hi.recently i conduct sensor circuitry.in source code,i notice that it use \xF8 to display temperature in degree celcius.what is the function of that?

I followed the instructions exactly, wiring was good, code was an exact replica of that given. Everything was correct, but I got -999 error message every time. I was using a three pin sensor, triple checked my wiring against the diagram. I increased the delay time to 3000ms. I was definitely using the correct older version of the library. After throwing out the sensor thinking it faulty, I have since discovered that the diagram above is does not apply to every dht11, that there are some where the pins are in a different order.

What does this mean? in every other arduino program I can find that uses additional libraries, the library is called first, then the code goes straight on to initialising the variables and describing the setup. I have not been able to find any other mention of the library name mentioned twice like this. A few people have asked about this, with no answers given. I cant even search for it because I dont know what to search by.

You will get 100% humidity if you put the sensor in water and it works. Use an SHT31-D breakout board to detect humidity and temperature. I’m sure you didn’t mean you are going to submerge the sensor. The SHT31-D is more accurate and easier to install and costs about the same as the DHT11 /22 both of which really aren’t accurate at all.

Ine is set up exactly as you show. I get -999.00 for both humidity and temperature. I have 2 different sensors (both DHT11) and I get the same readings. I even set this up on an RPI 3B+ and the readings were similar. 1.0 temp and humidity. What am I doing wrong?

I can not keep my display from blinking the temp and humidity values. It displays the value but blinks back and forth to -999.00. Thanks for the help I’m new

Still getting -999.00 on both temperature and humidity with LCD. If I connects ONLY DTH11 to Arduino with serial monitor it works fine, BUT if I connect it to LCD as described above it shows -999.00 In both LCD and serial monitor. It looks like it disables the DTH11 when connected to LCD. It does not work with dely(2000); or any other value.

i don’t know why but the LCD shows me white circles and within them the text is written also the temp and humidity are a constant 0 even with the serial monitor

It’s good idea for projects. I am thinking of building my own weather unit soon. Please can someone help me with a simulation circuit that will show the response graphs of dht11 for temperature and humidity

How would you configure Celsius to Fahrenheit when doing the LCD version? I read others commenting how with out the LCD but not with the code for using the LCD.

A few years back, I created a new home automation course at Santiago Canyon College in Orange, Calif. where I taught Computer Science and Robotics. I wanted to introduce my programming students to microcontrollers so they could have some fun controlling things around their home. The students never built anything like that so I came up with a couple introductory level lab projects for them to try out. I decided to make a simple "weather station" project so they could learn how to build a circuit on a breadboard, learn to program an Arduino, and how to write some code that could read multiple sensors and display the readings on a small LCD display.

You will discover that you must have the correct Arduino libraries installed for your particular sensor. This is especially true when working with LCD displays. The one we use in this project is version 1.2 so be sure to download both the LCD and the DHT-11 temperature libraries from my websitehere. Unzip them on your desktop and copy each folder to your Documents | Arduino | Library folder. Be sure to delete any existing libraries with the same name.

Always choose wire colors that make sense to you. Use red for power, black for ground, and another color for the output of your sensors. Be very careful when you wire up the LCD. On the connector, you must connect wires to the right place. For some reason, LCD"s even from the same manufacturer have the connector pins in different positions. Look at my comments under the LCD section below to see how I wired it. I also added a closeup photo of my connections.

Notice how I added the resistors to the breadboard and how the green and yellow wires go from the LCD connector to those resistors and THEN connect to the Arduino. The SCL & SDA pins on the LCD each need a pull--up resistor or it won"t display properly! The resistors provide a small amount of current to the LCD so the Arduino signals are interpreted correctly.

The DHT11 is an all-in-one temperature and humidity digital sensor that includes an internal resistive moisture measurement element and an NTC temperature measurement element and is connected to a high performance 8-bit micro-controller.

A simple external circuit connection is all that is needed to collect local temperature and humidity in real time. the DHT11 communicates with controllers such as micro-controllers using a simple single bus, requiring only one I/O port.

The Arduino Uno is an ATmega328P based micro-controller board. It has 14 digital input/output pins (6 of which can be used as PWM outputs), 6 analog inputs, a 16MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power socket, an ICSP header, and a reset button.

We just need to add the designed UI images through menu bar options for buttons, text boxes, background images, and page logic through the host computer, then generate the configuration file, and finally download it into the display and it is ready to run.

To develop based on our STONE TFT LCD, you first need to use to an upper computer development software STONE designer, in this upper computer, all screen-related settings are carried out in this upper computer, so how to download it, click the link below to go to the official website：https://www.stoneitech.com/support/download

First add a button control to the temperature, select “button” control, and draw the corresponding area; then in the right feature settings, set the button effect, here select page 2, that is, when the button is pressed, the corresponding area to display the effect of page 2; then select the page switch function, here select the No. 4 page, that is, when this button is pressed, the page will immediately switch to page 4, that is, the temperature display interface.

Under the temperature display interface, a text display control is needed to display the real-time temperature data passed by the Arduino, so it is necessary to add a data variable control, as shown in the following figure.

First of all, you need to set the variable address of the control, this address is very important, the data of the micro-controller can only be displayed by sending data to this address, and then set the format of the display, here choose 2 integers and 1 decimal.

If you feel that the font size of the display is too small to see clearly, you can also adjust the font size, and finally the alignment, I generally choose the center alignment, of course, there are also left-aligned, right-aligned to choose.

The STONE TFT LCD sometimes needs to control the micro-controller to achieve a two-way interaction, which is also the case here, and needs to implement the start and stop acquisition function, using the START button as an example.

First set the key effect, here select page 2, when the key is pressed it will display the effect of page 2, here there is no need to switch pages, so select null, it should be noted that it is also necessary to set a variable address.

After setting, click compile, then insert the U disk, wait for the recognition to finish and click download to copy the project into the U disk, and plug in the display to upgrade. In this way, the whole project is finished.

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.