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data to nodemcu web server

Display Sensor Data to NodeMCU Web Server

We setup a simple NodeMCU web server in our previous tutorial. There we controlled a LED from a web page hosted by the NodeMCU ESP8266 board! This time, we'll be displaying data from a sensor connected to the NodeMCU's analog pin.

In this tutorial, I'll be displaying data coming from a light dependent resistor (LDR) to our NodeMCU web server. You can use any sensor available to you as long as its output voltage is not more than the recommended maximum of 3.3 V.

The ESP8266 itself accepts only up to 1 V on its analog pin. Thankfully, the NodeMCU board has a built-in voltage divider.

The ESP8266 (which is the main chip on the NodeMCU) uses a 10-bit ADC. This means the input voltage from 0 to 3.3 V will be equivalent to 0 to 1024.

Wiring Diagram

Here's our simple circuit for this tutorial:

nodemcu sensor

I used a trimmer together with the LDR for voltage division so that I can adjust the "sensitivity" of my sensor.

Code

Upload the code and open your browser to the address shown on the serial monitor (see previous tutorial for more on this).

Output

Here's what the web page should look like:

nodemcu server page

Try to cover the LDR and refresh the page. It should show a different value.

That's it! Next up, we'll log our sensor data to a spreadsheet program like Google Sheets.

 

One comment

  1. Can I show this to my won website ??

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