Learn how to interface the A7672S 4G LTE GNSS module with Arduino for real-time GPS tracking and cellular communication.
This tutorial covers AT commands, SMS, voice, HTTPS requests, and circuit design—ideal for IoT projects in remote or mobile environments.
Compatible with Jio, Airtel, and VI, it's perfect for Indian makers and embedded developers.

Keypads are widely used input devices being used in various electronics and embedded projects. They are used to take inputs in the form of numbers and albhabets, and feed the same into system for further processing. In this tutorial we are going to interface a 4x4 matrix keypad with 8051 microcontroller.

The 16x2 will have 32 characters in total 16in 1st line and another 16 in 2nd line. Here one must understand that in each character there are 5x10=50 pixels so to display one character all 50 pixels must work together. But we need not to worry about that because there is another controller (HD44780) in the display unit which does the job of controlling the pixels.