Decimal to Hexadecimal Converter

In the design of Embedded Systems, converting numerical bases is a fundamental and crucial skill. This project will demonstrate how to build a small calculator to convert Decimal numbers to Hexadecimal numbers, leveraging the capabilities of an Arduino microcontroller board as the core processing unit. It will receive input via a 4x4 Keypad and display the results accurately on an LCD and the Serial Monitor.

Hardware Operation and Key Components

The core of this system consists of three systematically coordinated components:

1. Arduino Microcontroller: Functions as the Central Processing Unit (CPU), receiving signals from the Keypad, performing mathematical calculations, and sending display control commands.
2. 4x4 Keypad Matrix: An intelligent input device that uses the principle of scanning Rows and Columns to reduce the I/O pin usage of the Arduino. Each key press creates a short circuit between specific row and column lines, which the Arduino Library detects and converts into the desired numerical value.
3. Liquid Crystal Display (LCD): In this project, a 16x2 character display is commonly used to create an interactive User Interface, allowing users to simultaneously view both the entered Decimal number and the converted Hexadecimal number.

In-depth Processing Logic (Logic and Algorithms)

The conversion process in this system begins by continuously receiving input via the Keypad. When a user presses a number key, the Arduino stores these values in a variable and uses a calculation formula to accumulate the value (e.g., total = (total * 10) + pressedKey) to form a complete Decimal number.

Upon receiving a command to convert the value (typically assigned to the '#' or '*' button), the program will enter the base conversion function, which in computer engineering can be done in two main ways:

• Using Built-in Functions: In C/C++ language used with Arduino, we can directly print the value as Hexadecimal using commands like String(decimalValue, HEX) or sprintf(buffer, "%X", decimalValue).
• Mathematical Logic: If programming at a Low-level, the system will repeatedly divide the Decimal number by 16 and store the Remainder. The remainders are the values of each Hexadecimal digit (0-9 and A-F), starting from the least significant digit upwards.

Connection and Display

The processed data will be sent to two parallel channels:

1. Serial Monitor: Extremely useful during the Debugging phase, allowing developers to check internal variable values in Real-time.
2. LCD Display: The primary display for general users. Communication between Arduino and LCD often uses the I2C protocol to save wiring, or a Parallel 4-bit connection for applications requiring faster screen refresh rates.

This project not only demonstrates data base conversion but also serves as an excellent foundation for learning about Interrupt handling, Matrix scanning, and memory management in microcontrollers, which are essential skills for professional Embedded Systems engineers.