Introduction: WiFi Temperature Sensor Using 4Duino-24

About: 4D Makers is a group of curious engineers and enthusiasts who finds great satisfaction in creating and building anything from electronics.

In this project we will quickly create a ‘temperature monitor’ that measures the ambient temperature of a room or an outdoor space. The temperature is measured by TMP35 temperature sensor and is displayed on the 4Duino screen. The data is also sent to Thingspeak IoT platform which enables data logging over a period of time.

Step 1: How It Works

The TMP35 temperature sensor detects the room’s temperature in unit Celsius.

TMP35 communicates the temperature data to ATmega32U4 via Analog Input pin A0.

As per the program, ATmega32U4 converts this to unit Fahrenheit.

ATmega32u4 requests ESP8266 to send the current temperature to Thingspeak IoT platform.

ATmega32u4 requests Picaso to update the thermometer widgets and LED digits to display temperature in both units (C and F).

Step 2: Build


  • 4Duino
  • TMP 35 Temperature sensor
  • Bread Board
  • Jumper cables
  • µSD cable
  • Micro USB cable

Build the circuit as shown in the diagram.

Step 3: Set Up

Create yourself a ThingSpeak account at

  1. Create a new channel
  2. Get the channel API Key under channel settings / API Keys. This key will be later added in to your 4Duino code.
  3. Setup your Channel fields as shown in the third picture.

Step 4: Program

Workshop 4 – 4Duino Extended Graphics environment is used to program this project.

This project requires the Arduino IDE to be installed as Workshop calls the Arduino IDE for compiling the Arduino sketches. The Arduino IDE however is not required to be opened or modified to program the 4Duino.

  1. Download the project file here.Open this file using Workshop 4.
  2. Simply change the SSID and the PASSWORD to suit your router, on both the program.
  3. Enter your API key for the channel you wish to use.
  4. Connect the 4Duino to the PC using µUSB cable. Then navigate to the Comms tab and select the Comms port to which the 4Duino connected.
  5. Finally, go back to “Home” tab and now click on the “Comp’nLoad” button
  6. The Workshop 4 IDE will prompt you to insert a µSD card to the PC in order to save the widget images. Insert µSD card, select the appropriate drive and press button “OK”. If the µSD card has the widget images you can click button “No Thanks”.
  7. Insert the µSD card you saved the image files to into the 4Duino. After uploading the program in to the 4Duino, it will try to mount the µSD card. If the µSD card is not present it will print an error message

    You will notice that your 4Duino connects to reads and displays the temperature and meanwhile sends this data to Thingspeak IoT Platform.