Download !!EXCLUSIVE!! Dht11 Sensor Library For Arduino
Tanja Mcinnis
DHT Library: GitHub - adafruit/DHT-sensor-library: Arduino library for DHT11, DHT22, etc Temperature & Humidity Sensors (this one was included with the original Project, so it should technically be compatible with the code)
I'm trying to read multiple DHT sensors. I'd like to loop through a class array that contains the data for the DHT sensors (as well as other sensors, which I have removed from my code to increase readibility here). I'm using LadyAda's DHT library at GitHub - adafruit/DHT-sensor-library: Arduino library for DHT11, DHT22, etc Temperature & Humidity Sensors (tried also DHT22, but that didn't help). The problem seems to be that the pointer does not point to the DHT. Usually it fails to read, but sometimes there can be wrong data. I included a simple uint_8 pointer as well, to help in debugging. It gets written over sometimes by the temperature reading. Here's the code:
But even this library doesn't work.
The strange thing is that, this library doesn't work for Arduino UNO also, i found a post on this forum and found that, there is some problem in Adafruit library for DHT11 sensor, that's why i used the above library.
I used DHT11 which works properly with arduino uno but giving no wrong response with nodeMCU.
I used different libraries for each considering the architecture.
For uno DHTLib library and for nodeMCU DHT11 as guided in the previous answers of this thread. But I always get "timeout error" with nodeMCU. please help
Hey guys, I urgently need help for my school project. I am building a greenhouse, and part of the project is the ventilation. I need my fan speed to change according to the temperature measured by a DHT 22. I have found a really good website (Temperature Controlled Fan using Arduino - Hobby Project) that explains the code and everything else. I copied the code and tried to download the necessary library for the DHT from a link(GitHub - adafruit/DHT-sensor-library: Arduino library for DHT11, DHT22, etc Temperature & Humidity Sensors)
Adafruit DHT Humidity & Temperature Unified Sensor Library
This library also includes an optional class for the DHT humidity and temperature sensor which is designed to work with the Adafruit unified sensor library.
I have published an updated version of the DHT interrupt driven sensor library. It now supports DHT22 and DHT11 sensors. It has been published it as PietteTech_DHT in the libraries. The source is located at my github _DHT It includes updated samples, including one that shows timing information while reading two different sensors. As this library is very sensitive to timing I recommend a 1K pull-up resistor on the data line. It has been tested running at 3.3v with both DHT11 and DHT22 sensors mounted on a breadboard. I have not done any testing on longer wire runs. Remember to terminate the data line on any long wire run at the sensor with a 1K pull-up to 3.3v
@mtnscott, nice work on this updated library! During testing I experienced another crash with a single-sensor configuration and though the serial output stalled, the cloud connection and Spark.publish() kept functioning.
I am working on a small sensor hub project. What I want to ultimately do is create a sensor hub centred around an arduino Uno and use XBee ZB (S2) to transmit data from the sensor hub to another XBee connected to a RaspberryPi which will host the data online.
I have just 1 arduino uno board, so to check that the XBees and the DHT11 sensor is actually working, I have used a very modular approach. First I tested the DHT11 sensor using the Adafruit DHT Sensor Library (GitHub - adafruit/DHT-sensor-library: Arduino library for DHT11, DHT22, etc Temperature & Humidity Sensors) with the arduino. It worked.
NaN stands for "Not a Number". Sometimes the sensor fails to read and gives you a nan value. You can't do anything against it, but in the DHT.h library is a function called isnan(). So you can make a backup variable were you store the last value that was correct. Then you can check if your sensor reads nan and if he does you can print out the backup variable:
I've been working on a smart greenhouse project, much of which relies on the use of a DHT11 temperature and humidity sensor. I had gotten it working, but now for whatever reason it no longer works properly. I've been using the adafruit DHT11 temperature and humidity library, as it will work on an ESP32, and it had in the past, but I'm not sure what has changed. It's a 3 pin DHT11 module, not a 4 pin where you need to connect two pins together with a resistor.
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?
Looking forward to your answer.
Thanks in advance.
line 1 reads the integer value of the dht11 sensor pin
line 2 simply print the phrase temperature=
line 3 prints the value (temperature) given by the integer found in line 1. It is printed alongside the phrase in line 2
I found this article to be a whole lot clearer and easier to understand than most, but I do have a few points.
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.
My other point is a question about line 3 of the code given: dht DHT;
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.
Does this line of code actually do anything?
The 10K resistor helps to pull the signal high where required which improves the signal received from the sensor. Having some form of pull up resistor is recommended for this sensor. This will ensure that if there are periods where the sensor is left floating its not likely to cause issues by sending data which can be interpreted as valid data. Depending on the sensor library used the pull up resistor may be more or less important.
Below is the source code I used for my test. Here you can see I define the DHTTYPE as DHT11 but this can be used for a DHT22 sensor as well. This library simplifies using the sensor as you have two helper methods readHumidity and readTemperature. Using these will then return the sensor readings as a floating point number (a decimal).
First we need to included the DHT library which can be found from the Arduino official website, then define the pin number to which our sensor is connected and create a DHT object. In the setup section we need to initiate the serial communication because we will use the serial monitor to print the results. Using the read22() function we will read the data from the sensor and put the values of the temperature and the humidity into the t and h variables. If you use the DHT11 sensor you will need to you the read11() function. At the end we will print the temperature and the humidity values on the serial monitor.
This Grove - Temperature&Humidity Sensor and our another product Grove-Temperature&Humidity Sensor pro are sharing this library. No matter which product you are using, make sure that you have made the definition line of the sensor of your board into effect and commented out the definition lines of other specs. For example, the sensor we used on Grove - Temperature&Humidity Sensor is DHT 11. So the definition part of the sensor spec should be:
I'm new user for Labview and arduino and recently start to use the arduino with labview via Linx firmware and labview 2013 and doing some small projects or experiments but i have some difficulties with some sensors of arduino which i have it now the 37 kit like the 18B20 and DHT11 and so.
Once you have the "Arduino_Uno_Serial" example opened go to Sketch-> Include Library->Manage libraries. In the library manager search "DHT sensor library", once it comes up click on it and then select the install button that pops up. After it is installed restart Arduino IDE and then reopen "Arduino_Uno_Serial"
// Initialize DHT sensor.
// Note that older versions of this library took an optional third parameter to
// tweak the timings for faster processors. This parameter is no longer needed
// as the current DHT reading algorithm adjusts itself to work on faster procs.
DHT dht(DHTPIN, DHTTYPE);
The older library fixes the issue for me I think it has something to do with OMG. I also tried my ESP32 with OMG and I got the same wrong readings (dht library 1.4.4 and unified sensor 1.1.6). Using the same libraries (and versions) and the sketch I referred to earlier I got the correct values.
I bought a DHT11 sensor because I need to measure umidity and temperature and its output is a 40bit serial data. In fact, I don't know how to set a pin to read the 40bit output and then separe it in 5 bytes or read 1 byte a time. I've tried to use the UART library, but it gives me an error saying that "identifier 'bool' is undefined" and I can't find anything about this sensor on these boards over the internet.
I have downloaded the boltiot-arduino-helper and even put my credentials in the BoltDeviceCredentials.
I have a DHT11 and an LDR, I want to be able to read the data received in arduino from these two sensors regarding temperature, humidity and light, and send it to the cloud to make a graph out of it.