IoT IR Thermometer using MLX90614 & ESP8266 on Blynk
453.IoT IR Thermometer using MLX90614 & ESP8266 on Blynk In this project, we will use MLX90614 and ESP8266 to build our own IoT- based IR thermometer and then use the Blynk app to check t…
Know the mission before touching a wire.
Understand what you are making, prepare the right tools, and make the workbench safe.
Project details
IoT IR Thermometer using MLX90614 & ESP8266 on Blynk is a iot project. 453.IoT IR Thermometer using MLX90614 & ESP8266 on Blynk In this project, we will use MLX90614 and ESP8266 to build our own IoT- based IR thermometer and then use the Blynk app to check t…
- Source pages
- 1163-1168
- Named parts
- 4
- Build goal
- Working, tested prototype
Tools you need
- Digital multimeter
- Wire stripper and side cutters
- Soldering iron with a fine tip
- Current-limited bench supply
- Computer with a data-capable USB cable
Use eye protection, good lighting, and a clean insulated surface throughout the build.
Safety precautions
- Disconnect every power source before changing a connection.
- Check component polarity, pinout, and supply voltage twice.
- Use a current limit for the first power-up.
- Keep liquids, loose metal, and uninsulated wires away from the bench.
Gather, identify, and understand every part.
Use the standardized inventory, then open What's this? to learn each part's role, advantages, limitations, handling, and specifications.
What's this?Image, role, pros, cons, handling & specifications
MODULE LEARNING VIEWNodeMCU (ESP8266 12E Board)
A programmable controller that reads inputs, makes decisions, and drives the project's outputs.
What it does hereIt is the control centre and must use the documented board, pin map, supply, and logic level.
Buy / compare this part ↗Advantages
- Reprogrammable and reusable
- Large learning ecosystem
- Complex behaviour remains changeable
Limitations
- GPIO voltage and current are limited
- Some pins affect boot or communication
- Loads normally need a driver
Handling
- Disconnect power before rewiring
- Avoid static discharge
- Never power motors, relays, or pumps directly from GPIO
Specifications to verify
- Use the exact model, value, package, and rating listed for NodeMCU (ESP8266 12E Board); similar-looking parts are not always interchangeable.
- Confirm operating voltage, logic level, pinout, memory, USB interface, and maximum GPIO current.
What's this?Image, role, pros, cons, handling & specifications
IR Temperature Sensor (GY-906 MLX90614 IR Temperature
A sensor converts a physical condition into an electrical signal the circuit can measure.
What it does hereIt provides project input as an analogue, digital, resistive, frequency, or calibrated signal.
Buy / compare this part ↗Advantages
- Adds real-world awareness
- Can usually be tested independently
- Often supports calibration
Limitations
- Readings can drift
- Placement affects results
- Some sensors need warm-up or calibration
Handling
- Protect the sensing surface
- Observe supply voltage and polarity
- Keep signal leads away from noisy power wiring
Specifications to verify
- Use the exact model, value, package, and rating listed for IR Temperature Sensor (GY-906 MLX90614 IR Temperature; similar-looking parts are not always interchangeable.
- Confirm supply range, output type, measurement range, accuracy, response time, and pin order.
What's this?Image, role, pros, cons, handling & specifications
Sensor)
A sensor converts a physical condition into an electrical signal the circuit can measure.
What it does hereIt provides project input as an analogue, digital, resistive, frequency, or calibrated signal.
Buy / compare this part ↗Advantages
- Adds real-world awareness
- Can usually be tested independently
- Often supports calibration
Limitations
- Readings can drift
- Placement affects results
- Some sensors need warm-up or calibration
Handling
- Protect the sensing surface
- Observe supply voltage and polarity
- Keep signal leads away from noisy power wiring
Specifications to verify
- Use the exact model, value, package, and rating listed for Sensor); similar-looking parts are not always interchangeable.
- Confirm supply range, output type, measurement range, accuracy, response time, and pin order.
What's this?Image, role, pros, cons, handling & specifications
OLED Display (0.96" I2C OLED Display)
An output component turns an electrical control signal into light, sound, motion, switching, or displayed information.
What it does hereIt presents the circuit result or acts on the physical world.
Buy / compare this part ↗Advantages
- Makes system state visible
- Can be tested separately
- Supports clear troubleshooting
Limitations
- Loads may exceed controller current
- Polarity or driver direction can matter
- Inductive loads create voltage spikes
Handling
- Use the documented driver stage
- Check polarity and load current
- Add flyback protection for inductive loads
Specifications to verify
- Use the exact model, value, package, and rating listed for OLED Display (0.96" I2C OLED Display); similar-looking parts are not always interchangeable.
- Confirm voltage, current, polarity, interface, driver requirements, and duty cycle.
Connect one verified path at a time.
Explore the named components and standardized signal flow, then use Source Check to verify exact physical pins, values, and topology before applying power.
Trace this circuit.
IoT IR Thermometer using MLX90614 & ESP8266 on Blynk: interactive parts, standardized terminals, responsive anchored wires, student explanations, and the original circuit reference in one shared system.
Trace before wiring
Follow power, ground, inputs, processing, and outputs in that order. Never guess a pin from package shape alone.
Connect with power off
Make short, labelled connections and share a common ground only where the schematic requires it.
Inspect every joint
Check continuity, polarity, adjacent shorts, and loose connections before the first power-up.
Open all source diagrams and build views 4 visuals
Confirm the hardware-only control path.
This project does not include firmware in the source. The circuit itself provides the required behaviour.
How to connect
- Match every controller label to the circuit view and source pin map.
- Join grounds before signal wires when separate low-voltage supplies are used.
- Keep motors, relays, pumps, and other loads on a suitable driver and external supply.
Common mistakes
Reversed VCC/GND, board-label versus GPIO-number confusion, missing common ground, and charge-only USB cables.
Troubleshoot
Disconnect loads, continuity-test one path at a time, then test with a current limit.
Software preparation
No IDE, board package, library, or firmware upload is required for this project.
If you add a programmable controller as an extension, document its pin map separately.
How to upload code
The original design is implemented entirely in hardware, so proceed after verifying the circuit and supply.
Assemble, deploy, test, and troubleshoot.
Use the complete source notes in build order, then pass the final checks before calling the project finished.
Build in functional stages
- Power and regulation
- Controller or processing stage
- Inputs and sensors
- Outputs and loads
- Enclosure and strain relief
Power up safely
- Inspect unpowered continuity first
- Apply the lowest safe current limit
- Measure supply rails before signals
- Add one load at a time
- Record expected and actual results
Work from simple to complex
- Confirm power, ground, polarity, and orientation
- Compare each pin with the source
- Test inputs separately from outputs
- Replace only one variable at a time
- Power off before every correction
Follow the documented instructions.
These notes come from this project's source and remain in their original order.
Project overview
Project build note453.IoT IR Thermometer using MLX90614 & ESP8266 on Blynk In this project, we will use MLX90614 and ESP8266 to build our own IoT- based IR thermometer and then use the Blynk app to check the temperature. This DIY Infrared Thermometer is a low-cost, non-contact thermometer that can be used to measure the temperature of the body or of very hot objects. An infrared thermometer is a tool that measures an object's infrared radiation. Infrared radiation is a type of electromagnetic radiation that is below the range of light that we can see. Using the SMBus Protocol, which is similar to the I2C Protocol, the IR Temperature Sensor MLX90614 from Melexis can be easily connected to
any microcontroller. Here, we'll connect the MLX90614 sensor to the NodeMCU ESP8266 and the 0.96′′ OLED display. We will connect the ESP8266 to the WiFi network and send the temperature data, including both the ambient temperature and the temperature of the object, to the Blynk Application Dashboard. Blynk is an IoT platform that lets you quickly build interfaces for controlling and monitoring your hardware sensors from your smartphone. MLX90614 Contactless IR Temperature Sensor Melexis's MLX90614 is a digital infrared (IR) temperature sensor that doesn't need to be touched. The sensor can be used to find out how hot or cold something is between -70°C and 382.2°C. IR rays are used by the sensor to measure the temperature of an object without touching it.
The SMBus Protocol, which is similar to the I2C protocol, is how the MLX90614 sensor talks to the microcontroller. So, the sensor has four pins, which are VCC, GND, SDA, and SCL. The sensor works between 3.3V and 5V and needs 1.5mA of current. The sensor is accurate to 0.02°C. The sensor has a 17-bit ADC, which lets you read the temperature with a smaller resolution of 0.0007. The best way to get accurate data from a sensor is to put it at a distance of 2 cm to 5 cm with an 80° field of view.
Components Required
Project build noteNodeMCU (ESP8266 12E Board) IR Temperature Sensor (GY-906 MLX90614 IR Temperature Sensor) OLED Display (0.96" I2C OLED Display) Jumper Wires Breadboard
Circuit Diagram
Project build noteNow, let's connect the MLX90614 IR temperature sensor with the NodeMCU ESP8266 and the OLED display. Here is a picture of the connection.
Connect the VCC pin of the MLX90614 and the GND pin of the OLED display to the 3.3V pin of the NodeMCU ESP8266. In the same way, connect the SDA and SCL pins of the MLX90614 to the D2 and D1 pins of the NodeMCU.
Setting Up Blynk Application
Project build noteThe sensor data from the IoT-based IR thermometer is sent to any Cloud Platform. The Blynk Application is the cloud platform that I chose. Blynk is a great IoT platform that can be used to remotely control hardware, show sensor data, store data, visualize it, and do a lot of other cool things. So, get the Blynk app from the Google Play Store and install it. The App Store has downloads for people who use IOS. Once the app is installed, open it and sign up using your email address and password. Click on " New Project " on the Dashboard, and then choose "NodeMCU Board & Wifi Connection." Then click the Create button. Then, click the "+" sign in the upper right corner of the screen. Then, choose two gauges from the list and assign them to Virtual Pins 1 and 2 for Ambient Temperature and Object Temperature, respectively. You can move the
widget around on the screen or change its size as you like. Go to the settings and click on Send Email. The mail will get the authentication code. This code will be used in the ESP8266 Code to prove who you are. Arduino IDE is used to write the source code for NodeMCU ESP8266, MLX90614 and Blynk. The code can't be compiled without MLX90614 Library. It needs both the MLX90614 Library and the Blynk Library. Testing IoT Based IR Thermometer on Blynk After putting the code on the IoT Based IR Thermometer, you can start to test it. As soon as you upload the code, the 0.96′′ OLED Display starts showing both the Ambient Temperature and the Object Temperature. Then you can look at your Blynk App. The Blynk app will show the temperature in the form of a gauge, as shown in the picture below. So, this is how you can use MLX90614, ESP8266, and the Blynk application to make your own IoT-based IR thermometer. You can improve
this project by adding an Ultrasonic Sensor to the circuit and writing code to find the right distance. If you don't want to use Blynk, you can use any other IoT platform, like Thingspeak, Ubidots, or Adafruit IO.
You built IoT IR Thermometer using MLX90614 & ESP8266 on Blynk.
You followed the full workflow from understanding the mission to testing the finished project. That is a real engineering achievement - well done.
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