Skip to main content

87. Arduino Calculator

Hey everyone

Sorry I have not posted in a while. Today, I am back with an interesting project which is the Arduino Calculator. In this blog post, you will learn about the hardware components that are required for this project, the schematic and the explanation of the codes as well as a demonstration of this Arduino project.

Hardware components used in this project

  • Arduino Uno 
  • LCD display module with IIC interface - 16x2
  • Matrix Keypad - 4x4
  • Male-to-Female Jumper wires (x12)

Software required

  • Arduino IDE - latest version (preferred)

Schematic


Matrix Keypad


  • R1 - D9
  • R2 - D8
  • R3 - D7
  • R4 - D6
  • C1 - D5
  • C2 - D4
  • C3 - D3
  • C4 - D2


LCD Display module with IIC interface

  • GND (-) - Ground
  • VCC (+) - 5V
  • SDA - A4
  • SCL - A5

Coding

For this project, you will be needing the following libraries:
If you do not have the last two libraries installed, you can follow the hyperlink to read their documentation and access their repository. You can install the libraries from the respective Github repository or follow the instructions given in the respective Arduino reference page that can be accessed by following the hyperlink.

Create an LCD instance using the LiquidCrystal_I2C command and declare two variables that are of constant byte datatype. Name the variables as 'Rows' and 'Columns' and assign them to the value 4 as our matrix keypad has 4 columns and 4 rows. Create a few variables to store the value of the operands, operator and the answer.

Instantiate a keypad object that uses pins 9, 8, 7 and 6 as the row pins, and 5, 4, 3 and 2 as the column pins.
Create four user defined functions that will perform the calculations when 'A', 'B', 'C' or 'D' are pressed. Within void setup( ), initialize the LCD and set cursor to (4,0) and this is where you will print the welcome message but this is optional. Program the LCD display module to wait for 2 seconds and then clear its screen.

Within void loop( ),  create a character variable to store the value returned when any key is pressed. If any operator keys are pressed, print the value stored in the result variable and then print this operator. As the result variable has an initial value of 0, the first operand will be 0 in this case. If any number key is pressed, store the value returned in one of the number variables. If the '#' key is pressed, check the last value of the expression. If the last value is an operator, return an error message. If not, call the respective user defined function to perform the calculation and print the answer in the second row of the LCD. The operator variables should be assigned 0 and the operator variable must be empty after the calculation is done. If '*' key is pressed, clear the LCD. If any number key is pressed after a calculation is done and before clearing the screen (before '*' is pressed), you should program your microcontroller to automatically clear the screen.

Please watch the Youtube video in the next section of this post to get an understanding of how this works. 

Final Look


If you have any questions or suggestions regarding this project, please feel free to comment below. 





Comments

Post a Comment

Popular posts from this blog

51. Buzz wire game using Arduino

Hello everyone! This is my first Arduino project in 2020 and it is going to be a fun and simple project. You would have heard of the Buzz Wire, a steady hand game, and today you will be learning to make one using Arduino. Hardware components used in this project Arduino Nano USB Type A to mini B cable (for Arduino Nano) Solderless Breadboard - Mini and Full-size LEDs (x2) - Green and Red Resistors (x2) - 220 Ω  Active Buzzer module (KY-012) LCD display module with I2C interface - 16x2 Male-to-Male Jumper wires (x4) - 10cm Female-to-Male Jumper wires (x5) - 20 cm Jumpers (x5) - to reduce the usage of wires Copper wire  Tape (or any form of insulation)  Setup Your hardware setup must look somewhat similar to the ones in the images above. The beginning and end of the copper wire maze must be taped to prevent conductivity between the wire loop and maze. Connections LCD display module with I2C interface GND - Ground VCC - 5V SDA -...
Post a Comment
Read more

71. Buzz Wire Game ( Version 2.0 ) using Arduino

Hey Everyone! I hope that everyone's safe during this pandemic. Today I am going to explain you about the second version of my Buzz wire game. People who are bored of staying indoors can find this game pretty interesting and fun to play.  If you are a beginner, you can start off with my first version of this project :  51. Buzz wire game using Arduino   Hardware components used in this project Arduino Uno Solderless Breadboard (x2) - Full/ Full+ LCD display module with I2C module - 16x2 Potentiometer - B20K Push-buttons (x3) Resistor - 220 Ω Active Buzzer module (KY-012) LED - Red Copper Wire - 19/ 20 gauge thick Male-to-Male Jumper wires - 10cm and 20cm Wire - Long enough to connect the loop of copper wire to ground Other tools required for this project Cutting pliers - To cut the right amount of copper wire Round-nose pliers - To bend the copper wire and make a maze and loop Hardware setup Connections Wire Maze - D2 Wire loop - Ground (GND) B20K Potentiometer S - A0 (+)...
1 comment
Read more

70. Arduino Stopwatch and Timer

Hello everyone! Today I am going to explain you about making an Arduino Stopwatch and Timer, which can be used for time based projects. Read on further to learn more about this project. Hardware components used in this project Arduino Uno USB Type A/ B cable Solderless Breadboard - Full+ LCD display module with I2C interface - 16x2 Potentiometer - 10K Push-buttons (x5) Active Buzzer module (KY-012) LED - Red Resistors (x6) - 10kΩ (x5) and 220Ω (x1) Male-to-Male Jumper wires - 10cm and 20cm Jumpers - to reduce the usage of wires Hardware setup Connections 10K Potentiometer S - A0 (+) - 5V (-) - Ground (GND) Active Buzzer module S - D7 (+) - 5V (-) - Ground (GND) 16x2 LCD display module with I2C interface GND - Ground VCC - 5V SDA - A4 SCL - A5 Push-buttons (+) - 5V (-) - Ground (GND) S - D2, D3, D4, D5, D6 Coding Now, I will explain you about how this real-time project works and you can figure out the coding by this idea.  Push-buttons and their functions D2 - Set Countdown timer D3...
Post a Comment
Read more