Internship · Enerzi Microwave Systems, Belagavi · Apr to May 2022

IoT temperature and humidity logger

A NodeMCU ESP8266 reads a DHT11 sensor and pushes each reading over Wi-Fi to a Google Sheet. Below: the rows my prototype actually logged, and a browser simulator of the same pipeline.

NodeMCU ESP8266DHT11Arduino C++Wi-Fi / HTTPSGoogle Apps ScriptGoogle Sheets
SituationRoom conditions needed monitoring with no server to run.
TaskLog temperature and humidity remotely on a hobby budget.
ActionWired a NodeMCU ESP8266 with a DHT11 and pushed each reading over Wi-Fi to a Google Sheet.
ResultA live remote log at zero infrastructure cost; the simulator replays the pipeline.

Live demo

A simulator of the device-to-sheet pipeline. Readings are generated in your browser with DHT11-style noise; no sensor or Google account is involved.

Simulated dataRunning

Sheet1 (simulated Google Sheet, newest row first)

Temperature (°C)Humidity (% RH)Alert threshold / flagged reading

Data flow and wiring

Reference wiring for a DHT11 module on a NodeMCU. Pin choice in my build is not recorded in the files.

Reference sketch

A minimal Arduino C++ sketch and Apps Script receiver written for this page to show how the pipeline works. It is not my original project file.


    

  






  
Results
The nine rows my prototype wrote to the sheet. They repeat three value pairs and fall outside the DHT11's measuring range, so they are test values from the prototype rather than room measurements.

  

    
Logged readings, May to June 2022

    
    
Temperature (°C)Humidity (% RH)DHT11 upper limits: 50 °C, 90 % RH

    

  






  
How it works
Built during my internship at Enerzi Microwave Systems Pvt. Ltd., Belagavi, 1 April to 31 May 2022.

  
    
    
  1. Wire the sensor. Connected a DHT11 temperature and humidity sensor to a NodeMCU ESP8266 board (power, ground and one data pin).
    2. 
    
  2. Program the board. Wrote an Arduino C++ sketch that reads temperature (°C) and humidity (% RH) on a fixed interval.
    3. 
    
  3. Connect to Wi-Fi. The ESP8266 joins the local network and sends each reading as an HTTPS request.
    4. 
    
  4. Receive in Apps Script. A Google Apps Script web app takes the request and appends a row with date, time, temperature and humidity.
    5. 
    
  5. Monitor in Sheets. The Google Sheet becomes a live log that can be charted and checked against alert limits.
    6. 
  






  
Data