Introduction: Arduino Counting Timer for Announcement

This is a countdown timer that makes by using Arduino UNO and LCD monitor. The reason why I made this project because in our school(KCIS), we need to reserve lunch every Wednesday at 9:30 pm online. However, the most famous and the food that is in great demand have always be reserved already. Thus, this Arduino countdown timer will benefit be a lot by noticing me about the time. When you set up the time, the timer will start to countdown until 9:30 pm, after the time is up, the buzzer will beep for announcing me to go online and reserve the meal.

Step 1: Materials

  • Arduino UNO x1
  • LCD Monitor with I2C converter x1
  • Buzzer x1
  • Jumper wires
  • Potentiometerx1
  • Breadboard x1

Step 2: Build Up the Circuit


Check for "SDA" & "SCL" (on the back of the LCD monitor and the Arduino UNO board) when you build up the circuit.

Step 3: Enter the Code!!!

Here is the code


  • It has an error between +- 2 minutes
  • If the LCD monitor cannot show up anything, check for the code for first line of the code, it can be 0x3F or 0x27 depends on the different LCD monitor.

LiquidCrystal_I2C lcd(0x3F,20,4);

LiquidCrystal_I2C lcd(0x27,20,4);

Step 4: Decorate Your Timer

  1. Choose a shoe case that could fit all your materials inside
  2. Choose a position that you like and cut a hole for it(LCD & potentiometer)
  3. Start to cover your case with any kind of paper you like to make it beautiful(I choose kraft paper)
  4. Cut the paper into the size that is the most suitable then start to stable with glue or double-sided tape
  5. Finished covering and fit your timer inside.

Step 5: Completed

Finally, the Arduino countdown timer is completed. This time not only useful for students who study in Kang Chiao to reserve the lunch, but it can also use for many different types of situation. It is a very useful and technological timer for announcing people for their agenda.