ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (2023)

Learn how to publish DS18B20 temperature readings over MQTT with ESP8266 (NodeMCU) on any platform that supports MQTT or any other MQTT client. As an example, we will send the sensor readings to the Node-RED board and the ESP8266 will be programmed using the Arduino IDE.

ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (1)

Literature recommendations: What is MQTT and how does it work?

project description

The diagram below shows a high-level overview of the project we are going to create.

ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (2)
  • The ESP8266 requests temperature readings from the DS18B20 sensor. The readings are published inesp/ds18b20/temperaturais;
  • Node-RED is subscribedesp/ds18b20/temperaturaTheme. So it receives temperature readings from the DS18B20 and displays the readings on an indicator/chart;
  • You can get the reads on any other MQTT compatible platform and manipulate them however you like.

previous requirements

Before proceeding with this tutorial, be sure to review the following prerequisites.


We will be programming the ESP8266 using the Arduino IDE, so make sure you have the ESP8266 plugin installed.

  • Installation des ESP8266 Boards in der Arduino IDE (Windows, Mac OS X, Linux)


ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (3)

To be able to use MQTT, you need a broker. we will useinsect repellentinstalled on a RaspberryPi. ReadHow to Install Mosquitto Broker on Raspberry Pi.

You can use any other MQTT broker, including a cloud MQTT broker. We'll show you how to do this in code later.

If you are not familiar with MQTT, be sure to read our introductory tutorial:What is MQTT and how does it work?.

MQTT Libraries

To use MQTT with ESP8266 we use theAsynchronous MQTT client library.

Installing the Async MQTT client library

  1. Click here to download the Async MQTT client library🇧🇷 You should have a .zip folder in your Downloads folder
  2. Extract the .zip folder and you should getasync-mqtt-client-masterPasta
  3. Rename your folderasync-mqtt-client-masterProcliente_async_mqtt
  4. move thatcliente_async_mqttinto the Arduino IDE libraries installation folder
  5. Finally, open your Arduino IDE again

Alternatively you can go toDescribe>include library>add . postal codeLibrary and select the library you just downloaded.

Install the ESPAsync TCP library

In order to be able to use MQTT with ESP, you also need theESPAsync TCP-Bibliothek.

  1. Click here to download the ESPAsync TCP Client Library🇧🇷 You should have a .zip folder in your Downloads folder
  2. Extract the .zip folder and you should getESPAsyncTCP-MasterPasta
  3. Rename your folderESPAsyncTCP-MasterProESPAsyncTCP
  4. move thatESPAsyncTCPinto the Arduino IDE libraries installation folder
  5. Finally, open your Arduino IDE again

Alternatively you can go toDescribe>include library>add . postal codeLibrary and select the library you just downloaded.

DS18B20 Temperatursensorbibliotheken

To connect to the DS18B20 temperature sensor, you need to install theBiblioteca One Wire de Paul StoffregenIt is inDallas Temperaturbibliothek🇧🇷 Follow the steps below to install these libraries.

(Video) ESP32/ESP8266 Plot Sensor Readings in Real Time Charts - Web Server

1. Open your Arduino IDE and go toDescribe>include library>manage libraries🇧🇷 The library manager should open.

2. Type "a cable” in the search box and install Paul Stoffregen's OneWire library.

ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (4)

3. Then search for "Dallas' and install Miles Burton's DallasTemperature library.

ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (5)

After installing the libraries, restart your Arduino IDE.

To learn more about the DS18B20 temperature sensor, read our guide:ESP8266 DS18B20 Temperature Sensor with Arduino IDE (single, multiple, web server)

required parts

You will need the following parts for this tutorial:

You can use the links above or go find all the parts for your projects at the best price!

ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (6)

schematic representation

Connect the DS18B20 to the ESP8266 as shown in the schematic diagram below, with the DS18B20's data pin connected to theGPIO4(D2).

ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (7)


Copy the following code into your Arduino IDE. In order for it to work for you, you need to enter your network credentials as well as your MQTT broker details.

/* Rui Santos Full project details at Permission is granted at no charge to anyone who obtains a copy of this software and accompanying documentation. The above copyright notice and this permission notice must be included in all copies or substantial portions of the Software.*/#include <OneWire.h>#include <DallasTemperature.h>#include <ESP8266WiFi.h>#include <Ticker.h >#include <AsyncMqttClient.h>#define WIFI_SSID "REPLACE_WITH_YOUR_SSID"#define WIFI_PASSWORD "REPLACE_WITH_YOUR_PASSWORD" // Raspberri Pi Mosquitto MQTT Broker#define MQTT_HOST IPAddress(192, 168, 1, XXX)// For an MQTT broker in the cloud, enter the domain name //#define MQTT_HOST ""#define MQTT_PORT 1883// Temperature MQTT Topics#define MQTT_PUB_TEMP "esp/ds18b20/temperature"// GPIO where the DS18B20 is connected with const int oneWireBus = 4; // Configure an instance of oneWire to communicate with any OneWireOneWire device oneWire(oneWireBus); // Pass our OneWire reference to the Dallas temperature sensor DallasTemperaturesensors(&oneWire); // Temperature value float temp;AsyncMqttClient mqttClient;Ticker mqttReconnectTimer;WiFiEventHandler wifiConnectHandler ;WiFiEventHandler wifiDisconnectHandler ;Ticker wifiReconnectTimer;unsigned long prevMillis = 0; // Stores the last time the temperature was published const long interval = 10000; //Interval at which sensorvoid readings are published void connectToWifi() { Serial.println("Connecting to Wi-Fi..."); WiFi.begin(WIFI_SSID, WIFI_PASSWORD); } void onWifiConnect(const WiFiEventStationModeGotIP& event) { Serial.println("Connected to Wi-Fi"); connectToMqtt();}void onWifiDisconnect(const WiFiEventStationModeDisconnected& event) {Serial.println("Disconnected from Wi-Fi"); mqttReconnectTime.detach(); // Make sure we don't reconnect to MQTT while reconnecting to Wi-Fi wifiReconnectTimer.once(2, connectToWifi);}void connectToMqtt() { Serial.println("Connecting to MQTT... ") ; mqttClient.connect();}void onMqttConnect(bool sessionPresent) {Serial.println("Connected to MQTT."); Serial.print("Session exists: "); Serial.println(sessionPresent);}void onMqttDisconnect(AsyncMqttClientDisconnectRason Reason) {Serial.println("Disconnected from MQTT."); if (WiFi.isConnected()) {mqttReconnectTimer.once(2, connectToMqtt); }}/*void onMqttSubscribe(uint16_t packageId, uint8_t qos) { Serial.println("Subscription confirmed."); Serial.print("PackageID:"); Serial.println(PackageID); Serial.print(" qos: "); Serial.println(qos); } void onMqttUnsubscribe(uint16_t packageId) { Serial.println("Unsubscribe confirmed"); Serial.print("PackageID:"); Serial.println(packetId);}*/void onMqttPublish(uint16_t packetId) { Serial.print("Publishing confirmed."); Serial.print("PackageID:"); Serial.println(packetId); } void setup() { sensors.begin(); Serial.begin(115200); Serial.println(); wifiConnectHandler = WiFi.onStationModeGotIP(onWifiConnect); wifiDisconnectHandler = WiFi.onStationModeDisconnected(onWifiDisconnect); mqttClient.onConnect(onMqttConnect); mqttClient.onDisconnect(onMqttDisconnect); //mqttClient.onSubscribe(onMqttSubscribe); //mqttClient.onUnsubscribe(onMqttUnsubscribe); mqttClient.onPublish(onMqttPublish); mqttClient.setServer(MQTT_HOST, MQTT_PORT); // If your broker requires authentication (username and password), set it below //mqttClient.setCredentials("REPlACE_WITH_YOUR_USER", "REPLACE_WITH_YOUR_PASSWORD"); connectToWifi();}void loop() { unsigned long currentMillis = millis(); // Every X seconds (interval = 10 seconds) // Publish a new MQTT message if (currentmillis - oldMillis >= interval) { // Store the last time a new metric was published OldMillis = currentMillis; // New readings from temperaturesensors.requestTemperatures(); // Temperature in degrees Celsius temp =sensors.getTempCByIndex(0); // Temperature in Fahrenheit //temp =sensors.getTempFByIndex(0); // Publish an MQTT message on the topic esp/ds18b20/temp uint16_t packageIdPub1 = mqttClient.publish(MQTT_PUB_TEMP, 1, true, String(temp).c_str()); Serial.printf("Publication on topic %s at QoS 1, Package ID: %i ", MQTT_PUB_TEMP, Package IdPub1); Serial.printf("message: %.2f \n", temporary); 🇧🇷

see raw code

How the code works

In the next section, all required libraries are imported.

#include <OneWire.h>#include <DallasTemperature.h>#include <ESP8266WiFi.h>#include <Ticker.h>#include <AsyncMqttClient.h>

Please enter your network credentials in the following lines.


Enter the Raspberry Pi's IP address for the ESP8266 to connect to your broker.

#define IP address MQTT_HOST(192, 168, 1, 106)

If you are using a cloud MQTT broker, enter the broker's domain name, for example:

#define MQTT_HOST ""

Configure El Puerto MQTT.

#define MQTT_PORT 1883

We will post at temp noesp/ds18b20/temperaturaTheme. If you want to change the theme, change it on the next line.

(Video) DHT11 & NodeMCU Tutorial || Humidity & Temperature Monitoring over Thingspeak

#define MQTT_PUB_TEMP "esp/ds18b20/temperatura"

You can create more themes if you want.

Please configure your DS18B20 in the following lines. In our case it is related to thatGPIO4🇧🇷 You can connect it to any other GPIO.

// GPIO where the DS18B20 is connected to const int oneWireBus = 4; // Configure an instance of oneWire to talk to any OneWire device OneWire oneWire(oneWireBus); // Pass our OneWire reference to the Dallas temperature sensorDallasTemperaturesensors(&oneWire);

ÖTemperatureThe variable contains the temperature value of the DS18B20 temperature sensor.

fluctuation temperature;

Create oneAsyncMqttClientnamed objectmqtt-Clientto handle the MQTT client and timers to reconnect to your MQTT broker and router when the connection is lost.

AsyncMqttClient mqttClient;Ticker mqttReconnectTimer;WiFiEventHandler wifiConnectHandler;WiFiEventHandler wifiDisconnectHandler;Ticker wifiReconnectTimer;

Then create some timer helper variables to publish the readings every 10 seconds. You can change the delay time torestVariable.

unsigned previous longMillis = 0; // Stores the last time the temperature was published const long interval = 10000; // Interval at which sensor readings are posted

MQTT functions: connect to WiFi, connect to MQTT and WiFi events

We do not add comments to the functions defined in the following section of code. These functions are included in the Async Mqtt Client library. The function names are self-explanatory.

For example himconnectToWifi()Connect your ESP8266 to your router:

void connectToWifi () {Serial.println ( "Conectando a Wi-Fi ..."); WiFi.begin (WIFI_SSID, WIFI_PASSWORD);}

ÖConnection to Mqtt()Connect your ESP8266 to your MQTT broker:

void connectToMqtt () { Serial.println ( "Conectando ao MQTT ..."); mqttClient.conectar();}

ÖonMqttConnect()The function is executed after starting a session with the broker.

void onMqttConnect(bool sessionPresent) {Serial.println("Connected to MQTT."); Serial.print ("Aktuelle Sitzung: "); Serial.println (Presentsession);}

MQTT functions: detach and publish

When the ESP8266 loses the connection to the MQTT broker, it calls theonMqttDisconnectFunction that prints this message on the serial monitor.

void onMqttDisconnect (AsyncMqttClientDisconnectRason Reason) {Serial.println ("Desconectado do MQTT."); if (WiFi.isConnected()) {mqttReconnectTimer.once(2, connectToMqtt); }}

When you send a message to an MQTT topic, theonMqttPublish()function is called. Prints the package ID in Serial Monitor.

void onMqttPublish(uint16_t packageId) { Serial.print("Publishing confirmed"); Serial.print("PackageID:"); Serial.println(package id);}

Basically, all of the functions we just mentioned are callback functions. Therefore, they are executed asynchronously.


Now let's get to thoseconfigure()🇧🇷 Initialize the DS18B20 sensor and start serial communication.


The next two lines create handlers that allow the MQTT broker and the Wi-Fi connection to reconnect when the connection is lost.

wifiConnectHandler = WiFi.onStationModeGotIP(onWifiConnect);wifiDisconnectHandler = WiFi.onStationModeDisconnected(onWifiDisconnect);

Finally assign all callback functions. This means that these functions are carried out automatically when required. For example, when the ESP8266 connects to the broker, it automatically calls theonMqttConnect()function and so on.

mqttClient.onConnect(onMqttConnect);mqttClient.onDisconnect(onMqttDisconnect);//mqttClient.onSubscribe(onMqttSubscribe);//mqttClient.onUnsubscribe(onMqttUnsubscribe);mqttClient.onPublish(onMqttPublish);mqttClient.setServer(MQTT_HOST, MQTT_PORT);

Broker Authentication

If your broker requires authentication, uncomment the following line and enter your credentials (username and password).


Finally, connect to Wi-Fi.



nocycle(), create a timer to post new temperature readings foresp/d18b20/temperaturatopic every 10 seconds.

(Video) Visualize Your Sensor Readings from Anywhere in the World (ESP32/ESP8266 + MySQL + PHP)

unsigned long currentMillis = millis(); // every X seconds (interval = 10 seconds) // post a new MQTTif(currentMillis - previousMillis >= interval) { // store the last time a new reading was posted previousMillis = current Millis; // New readings from temperaturesensors.requestTemperatures(); // Temperature in degrees Celsius temp =sensors.getTempCByIndex(0);

If you prefer the temperature in Fahrenheit, comment out the following line:

//temp = sensores.getTempFByIndex(0);

Learn more about the DS18B20 temperature sensor:ESP8266 DS18B20 Temperature Sensor with Arduino IDE (single, multiple, web server).

Post in topics

To post a message to an MQTT topic, use the following line:

uint16_t paqueteIdPub1 = mqttClient.publish(MQTT_PUB_TEMP, 1, grün, String(temp).c_str());

If you want to post further reading on other topics, you can duplicate this line at the top of thecycle().

Basically use thethe mail()method notmqtt-ClientPurpose of publishing data on a topic. Othe mail()The method accepts the following arguments, in this order:

  • Subject MQTT(const char*)
  • QoS (uint8_t): Quality of service: can be 0, 1 or 2
  • Hold flag (bool): Hold flag
  • Payload (const char*)

QoS (Quality of Service) is a way to ensure that the message is delivered. It can be one of the following levels:

  • 0: The message is delivered once or not at all. The message is not recognized. There is no possibility of duplicate messages;
  • 1: The message is delivered at least once, but can be delivered more than once;
  • 2: the message is always delivered exactly once;
  • Learn more about MQTT QoS.

Laden of Codes

With the Raspberry Pi powered on and the Mosquitto MQTT runner running, upload the code to your ESP8266.

Open Serial Monitor with a baud rate of 115200 and you will see the ESP8266 start sending messages.

ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (8)

Prepare the Node-RED board

The ESP8266 publishes temperature readings every 10 secondsesp/ds18b20/temperaturaTheme. Now you can use any MQTT capable board or any other MQTT capable device to subscribe to this topic and get the reads.

As an example, let's create a simple flow using Node-RED to subscribe to this topic and display the metrics in an indicator or chart.

If you don't have Node-RED installed, follow the tutorials below:

  • Introducing Node-RED on the Raspberry Pi
  • Installation and first steps with the Node-RED panel

With Node-RED running on your Raspberry Pi, go to your Raspberry Pi's IP address followed by: 1880.


The Node-RED interface should open. Drag an MQTT node, a Graph node, and a Caliber node into the stream.

ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (9)

Click on the MQTT node and edit its properties as follows:

ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (10)

The Server field refers to the MQTT broker. In our case, the MQTT broker is the Raspberry Pi, so it's set to localhost:1883. If you are using a Cloud MQTT broker, you must change this field. Enter the topic you want to subscribe to and the QoS.

Set the following properties for the indicator node.

(Video) Temperature logger _ Read each minute but send once every 24h [esp8266, WiFi, MQTT, Deep sleep]

ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (11)

Edit the chart node as follows:

ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (12)

Connect your nodes as shown below:

ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (13)

Finally, implement your flow (press the button in the top right corner).

ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (14)

Alternatively you can go toMenu>importand copy the following into yoursclipboardto create your Node-RED stream.

[{"id":"3eb4b485.bb948c","type":"mqtt de","z":"b01416d3.f69f38","name":"","subject":"eng/ds18b20/temperatur", "qos": "1", "Datentyp": "Auto", "Agent": "8db3fac0.99dd48", "x": 930, "y": 120, "Kabel": [["706fecd4.6f91a4 " , "47ed6377.491d6c"]]},{"id":"706fecd4.6f91a4","type":"ui_gauge","z":"b01416d3.f69f38","name":"","group" : " 37de8fe8.46846","order":2,"width":0,"height":0,"gtype":"calibrator","title":"Temperature","label":"ºC","format ":"{{value}}","min":0,"max":"40","colors":["#00b500","#f7df09","#ca3838"],"sec1": " " ,"seg2":"","x":1190,"y":100,"wires":[]},{"id":"47ed6377.491d6c","type":"ui_chart","z " :"b01416d3.f69f38","name":"","group":"2b7ac01b.fc984","order":4,"width":0,"height":0,"label":"Temperatur " , "chartType":"line","legend":"false","xformat":"HH:mm:ss","interpolate":"linear","nodata":"","point":false , "ymin":"","ymax":"","removeOlder":1,"removeOlderPoints":"","removeOlderUnit":"3600","cutout":0,"useOneColor":false,"colors " : ["#1f77b4","#aec7e8","#ff7f0e","#2ca02c","#98 df8a","#d62728","#ff9896","# 9467bd"," #c5b0d5"],"useOldStyle":false,"outputs":1,"x":1190,"y":160,"wires ":[[]]},{"id":"8db3fac0 .99dd48", "type":"mqtt-broker","z":"","name":"","broker":"localhost" ,"port":"1883","clientid":"" ,"usetls":false,"compatmode":false,"keepalive":"60","cleansession":true,"birthTopic":""," geburtQos":"0","birthPayload":"","closeTopic":" ","closeQos":"0","closePayload":"","willTopic":"","willQos":"0" ,"willPayload":""},{"id":" 37de8fe8.46846", "type":"ui_group","z":"","name":"DS18B20","tab":"53b8c8f9. cfbe48","order":1,"disp":true, "width": "6","collapse":false},{"id":"2b7ac01b.fc984","type":"ui_group"," z":"","name":"SENSORS","tab":"99ab8dc5.f435c","disp":true,"width":"6","collapse":false},{"id": "53b8c8f9.cfbe48","type":"ui_tab","z":"","name":"Home","icon":"dashboard","order":2,"disabled":false," hidden":false},{"id":"99ab8dc5.f435c ","type ":"ui_tab","z":"","name":"HTTP","icon":"panel","command ":1,"deaktiviert":false,"hidden":false }]

see raw code


Navigate to your Raspberry Pi's IP address followed by:1880/ui.


You must have access to the current sensor readings on the dashboard (display and graph).

ESP8266 NodeMCU MQTT - Post DS18B20 Sensor Readings (Arduino) | Random nerd tutorials (15)

Is this! You have your ESP8266 board to publish sensor readings to Node-RED via MQTT.


MQTT is an excellent communication protocol for exchanging small amounts of data between devices. In this tutorial, you learned how to send DS18B20 temperature readings to an MQTT topic using the ESP8266. You can then use any home automation device or platform to subscribe to this topic and get readings.

Instead of a DS18B20 you can use any other sensor:

  • ESP8266 MQTT - Post BME280 temperature, humidity and pressure readings
  • ESP8266 MQTT - Post DHT11/DHT22 temperature and humidity measurements

We hope you found this tutorial useful. If you're interested in learning more about the ESP8266, take a look at our resources:

  • Home automation with ESP8266
  • MicroPython programming with ESP32 and ESP8266
  • More ESP8266 NodeMCU projects…

Thank you for reading.


How to connect DS18B20 temperature sensor with NodeMCU? ›

Connecting DS18B20 sensors to ESP8266 NodeMCU is fairly simple. Start by connecting all the DS18B20s in parallel i.e. common all the VDD pins, GND pins & signal pins. Then connect VDD to the 3.3V out, GND to ground and connect signal pin to digital pin D2 on ESP8266 NodeMCU.

How to connect DS18B20 to ESP8266? ›

Circuit diagram Interfacing DS18B20 Temperature sensor with ESP8266. As from the above schematic diagram the VCC and GND of sensor are connected to 3.3V and GND of ESP8266, and DATA pin is connected to pin D2 of ESP8266. A 4.7k Ohm pull up resister is connected to data pin from 3.3V supply for stable data communication ...

What is the recommended resistance with DS18B20 sensor? ›

The datasheet of the DS18B20 sensor recommends a 4.7K ohms resistor as pullup but you can pull the sensor up with a 10K resistor. That should also work if you have a 10K in hand.

Why does DS18B20 need a resistor? ›

As a result, we need a pull-up resistor either to 'pull up' the power pin voltage near the voltage of the data line (when you want to avoid running a 'power' wire), or to pull up the data bus to logic 1 when it is idle if you decide to use a power wire, but don't want to use the internal pull-up resistor in the ...

Is DS18B20 analog or digital? ›

DS18B20 Temperature Sensor is a 1-wire digital sensor which can reach the digital data resolution up to 12bits and has ±0.5°C accuracy from -10°C to +85°C. A pull-up resistor is added to get stable data from the data line.

How connect DS18B20 to Arduino? ›

Connecting DS18B20 With Arduino
  1. Connect the GND pin or the black wire of the sensor to the GND.
  2. Connect the Vcc pin or the Red wire of the sensor to the 5V supply.
  3. Connect the signal pin or the yellow wire to the 5V through a 4.7kohm resistor and also connect this signal pin to the Digital Pin no-12 of Arduino.
Jun 7, 2020

Which temperature sensor is best for ESP8266? ›

DHT11 Temperature and Humidity sensor is quite popular as it can be easily used with 5V and 3.3V compatible controller boards like Arduino Boards, Nodemcu ESP8266, and ESP32, etc. With the help of the DHT11 Temperature and Humidity sensor you can monitor Temperature and humidity. Temperature Range: 0°C to 50°C.

How accurate is DS18B20? ›

The DS18B20 has an accuracy of ±0.5°C Accuracy from -10°C to +85°C, but its still possible yours might be outside the error range depending were you got them from there of lots of rejects for sale on the web.

Can DS18B20 measure body temperature? ›

The measurement results displayed on the LCD is an indicator that the sensor DS18b20 works appropriately or error. Body temperature and heartbeat test results can see in figure 4.

What is the reading of DS18B20 sensor? ›

The DS18B20 temperature sensor is fairly precise and does not require any external components to function. It has a temperature range of -55°C to +125°C and an accuracy of ±0.5°C. The temperature sensor's resolution can be set to 9, 10, 11, or 12 bits.

How to read temperature from DS18B20? ›


The core functionality of the DS18B20 is its direct-to-digital temperature sensor. The resolution of the DS18B20 is configurable (9, 10, 11, or 12 bits), with 12-bit readings the factory default state. This equates to a temperature resolution of 0.5°C, 0.25°C, 0.125°C, or 0.0625°C.

How many ohms should sensor read? ›

Many sensors that use communication protocols require a minimum of 150Ω to 180Ω, so choose the Ohm value on the multimeter that is closest to, yet bigger than, 200Ω.

Why 4.7 K resistor in DS18B20? ›

The 4.7k resistor lets you drive systems with much higher capacitance (dozens of sensors at multiple meters). For playing around or a single sensor, there really is no need.

What are the 4 types of temperature sensor that used to sense the temperature? ›

There are four types of temperature sensors that are most commonly used in modern-day electronics: thermocouples, RTDs (resistance temperature detectors), thermistors, and semiconductor based integrated circuits (IC).

What is the GPIO where the DS18B20 is connected to? ›

Instantiate DS18B20 Sensor

Define the GPIO that the DS18B20 data pin is connected to. In this case, it's connected to GPIO 4.

How do you calibrate a DS18B20 sensor? ›

To calibrate a thermo-sensor, you have to measure something of which you know the temperature. The simple way to do it at home is using boiling water and a bath of melting ice, also called a "triple-point" bath. In those cases we know that water boils at 100°C on the sea level.

What is the temperature range of DS18B20? ›

It has an operating temperature range of -55°C to +125°C and is accurate to ±0.5°C over the range of -10°C to +85°C. In addition, the DS18B20 can derive power directly from the data line (“parasite power”), eliminating the need for an external power supply.

How accurate is Arduino temperature sensor? ›

As for the temperature, the sensor works perfectly for temperatures between – 40℃ and 85℃ with an accuracy of ±1℃.

How many DS18B20 are there in Arduino? ›

Simply we will connect Multiple DS18B20 Temperature Sensors to Arduino and display the temperature values of all the sensors in degree celsius or Fahrenheit. Only one digital pin of Arduino is required to connect several temperature sensor. We can connect maximum of 1024 sensors using I2C Protocol.

What is the most accurate temperature sensor for Arduino? ›

DHT11 is perhaps the most popular, widely used, and reliable temperature and humidity sensor module for Arduino based projects. It can measure humidity from 20% to 90% RH and temperature from 0 to 50 degrees Celsius.

What are disadvantages of ESP8266? ›

  • Memory limitations.
  • Less powerful.
  • Processing power is weaker than the microcontroller.
  • Requires effort to accomplish some tasks such as scheduling and database storage.
Jul 9, 2018

Is ESP8266 obsolete? ›

No - absolutely not.

How long can ESP8266 run continuously? ›

Typical current consumption of an ESP8266 module in normal operation mode is 70mA. So, if we run an ESP module continuously in normal mode it will run only for one and a half day.

What are the disadvantages of DS18B20? ›

The only drawback of the sensor is that once it is worn out, then it doesn't have any replaceable parts. You have to change the sensor in all.

Which temperature sensor has highest accuracy? ›

An RTD is the most accurate and stable temperature sensor and is more linear than a thermocouple or thermistor. However, RTDs are the slowest and most expensive temperature sensors.

Which temperature route is the most accurate? ›

Rectal temperatures are considered most accurate indication of the body's temperature. Oral and axillary temperature readings are about ½° to 1°F (. 3°C to . 6°C) below rectal.

What is the difference between DS18B20 and LM35? ›

LM35 can measure the temperature between −55°C to 150°C but DS18B20 can measure between −50°C to 125°C. 1 digital output pin of Arduino can be used to connect multiple DS18B20 but it doesn't happen with LM35.

What is the difference between DS18B20 and DS18S20? ›

The DS18B20 differs from the DS18S20 in an important respect: the designer can select the desired resolution by using the configuration register. This flexibility allows the user to reduce the ADC conversion time and conserve power if higher resolutions are not required.

What are the 5 sites to measure a patient's temperature? ›

Ways to Take a Temperature
  • Rectal. The thermometer is placed in the child's bottom. ...
  • Oral. The thermometer is placed in the mouth under the tongue. ...
  • Axillary. The thermometer is placed in the armpit.
  • Tympanic. The thermometer is placed in the ear.
  • Temporal artery. The thermometer scans the surface of the forehead.

How do you read a temperature sensor temperature? ›

How to measure temperature! Using the TMP36 is easy, simply connect the left pin to power (2.7-5.5V) and the right pin to ground. Then the middle pin will have an analog voltage that is directly proportional (linear) to the temperature. The analog voltage is independent of the power supply.

What is the default resolution of DS18B20? ›

The core functionality of the DS18B20 is its direct-to-digital temperature sensor. The resolution of the temperature sensor is user-configurable to 9, 10, 11, or 12 bits, corresponding to increments of 0.5°C, 0.25°C, 0.125°C, and 0.0625°C, respectively. The default resolution at power-up is 12-bit.

What is the operating voltage of DS18B20? ›

-0.5V to +6.0V Operating Temperature Range ......................... -55°C to +125°C Storage Temperature Range ............................

What are the 3 ways to measure temperature? ›

Three different scales are commonly used to measure temperature: Fahrenheit (expressed as °F), Celsius (°C), and Kelvin (K).

What information is in DS18B20? ›

The DS18B20 is one type of temperature sensor and it supplies 9-bit to 12-bit readings of temperature. These values show the temperature of a particular device. The communication of this sensor can be done through a one-wire bus protocol which uses one data line to communicate with an inner microprocessor.

What is a good continuity reading in ohms? ›

If your multimeter reads 0 ohms, it means that there is perfect continuity in the wire, fuse, battery, or device. Most multimeters will beep continuously when testing a connection with good or perfect continuity. A constant 0 indicates a perfect connection.

How do you know if a sensor is bad? ›

While the damage may seem small initially, the longer you drive with a bad oxygen sensor, the worse the damage will become. Eventually, you may experience rough idling, poor acceleration, engine misfires, an illuminated check engine light, and failed emission tests.

Can I use 10K resistor instead of 1k? ›

By the way, ten 10K resistors in parallel equals 1K total resistance.

Why use 10K pull-up resistor? ›

Pull-up resistors are used in electronic logic circuits to ensure that inputs to logic systems settle at expected logic levels, if external devices are disconnected or high-impedance is introduced.

Is a 1 or 5 resistor better? ›

If the tolerance ratings you are referring to is the last color band, then the resistors with the smaller tolerance value is much better… Like for example, a 1% tolerance is preferred than a 5% or 10% , since it is an indication of precision in resistance value..

Which temperature sensor is fastest? ›

The fastest-possible temperature sensor is an exposed tip thermocouple.

What are the two most commonly used contact temperature sensors in the industry? ›

The most common contact temperature sensors are liquid-in-glass thermometers, thermocouples, RTDs, and thermistors.

What is the most important part of a temperature monitoring system? ›

Thermocouples, thermistors, and RTDs are the three most important types of temperature monitoring systems and your selection should be based on your purpose.

Does DS18B20 need a resistor? ›

One-wire devices need a pull-up resistor connected to their signal line to be properly read by your board. Luckily all the DS18B20 sensors sold by Adafruit include the necessary pull-up resistor!

Can we connect sensors to NodeMCU? ›

Connect the two pins of the moisture sensor to the two pins on the Amplifier circuit using jumper wires. Connect the Vcc from the Amplifier to the 3.3V pin on the NodeMCU. Connect the GND pin to the ground (GND) pin on the NodeMCU. Connect the Analog pin to the A0 pin on the NodeMCU.

How do you wire a DS18B20 sensor? ›

To avoid overheating and damage, make sure the DS18B20 is connected properly. If you're using the waterproof version of the DS18B20, connect the red wire to 5V, the black wire to ground, and the yellow wire to digital pin 2 on the Arduino. You still have to connect a 4.7K pullup resistor between the data and the 5V.

How does temperature sensor connect to NodeMCU? ›

Your client(mobile, desktop or laptop) must be connected to the same WiFi router to which you are going to connect your server(nodemcu). Select correct board in your arduino ide and upload the code in nodemcu. After uploading the code in nodemcu open arduino serial monitor.

How to connect temperature sensor with ESP8266? ›

IoT Temperature Sensor With ESP8266
  1. Introduction: IoT Temperature Sensor With ESP8266. ...
  2. Step 1: Concept and Components Required. ...
  3. Step 2: Get Arduino IDE to Work. ...
  4. Step 3: Connect the Temperature Sensor. ...
  5. Step 4: Setting Up the Cloud Webserver (optional) ...
  6. Step 5: Upload the Temperature Sensor Sketch.

Is NodeMCU ESP8266 better than Arduino? ›

Advantages of NodeMCU over Arduino UNO:

Better Processor & Memory: NodeMCu comes with an 80MHz of clock speed and 4MB of flash memory. Built-in TCP/IP Stack - IoT Ready: The NodeMCU contains a Wifi connection and can connect to the internet through Wifi.

Can we use Arduino and NodeMCU together? ›

Note that when you use the NodeMCU board with the Arduino IDE ,it will write directly to the firmware, erasing the NodeMCU firmware.So if you want to back to Lua SDK,use the “flasher” to re-install the firmware.

Can NodeMCU read analog input? ›

A NodeMCU has 10 bit ADC which means it scales an analog signal in a range of 0-1023. In this example an analog input is taken and it displayed on an LED and the serial monitor.In order to show the input result on LED, Mapping of input value is need.

What are the colors on DS18B20 wiring? ›

If your sensor has three wires - Red connects to 3-5V, Blue/Black connects to ground and Yellow/White is data.

What are the 3 wires on a map sensor? ›

A MAP sensor is a 3-wire sensor. The three wires are the sensor ground, a 5-volt reference and a signal wire. At idle, the output of a MAP sensor is typically 0.85 volts to 1.3 volts. A faulty MAP sensor may affect the mixture of air and fuel to the extent that the engine will surge.

What is the temperature of ESP8266 DS18B20? ›

Here's a summary of the most relevant specs of the DS18B20 temperature sensor: Communicates over one-wire bus. Power supply range: 3.0V to 5.5V. Operating temperature range: -55ºC to +125ºC.

Which temperature sensor is used for NodeMCU? ›

LM35 is a temperature sensor that can measure temperature in the range of -55°C to 150°C. It is a 3-terminal device that provides an analog voltage proportional to the temperature. The higher the temperature, the higher is the output voltage.

What are the 3 modes of ESP8266? ›

The ESP8266 has three modes; mode 1 which is “Station” mode, mode 2 which is “Access Point” mode, and mode 3 which is “AP + Station” mode where the device can act as a WiFi client and access point simultaeously.


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3. Arduino temperature sensor – DHT22 Temperature and humidity vs. DS18B20 Temperature 1-Wire
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4. Programming Multisensor Shield for ESP8266 - Part 2
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6. How to Get Started with MQTT
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