Arduino Projects

Arduino Stopwatch with OLED has Start Stop Reset button

Learn how to build an Arduino Stopwatch using OLED display which has buttons to start, stop and reset the time.


In this simple Arduino project, you will learn how to build a stopwatch by interfacing an OLED display with Arduino and push buttons. Here we are using 3 push buttons to start, stop/pause and reset the timer of the stopwatch. We are making the stop watch to measure from milliseconds to minutes by using a special function millis().

Millis() function is powerful and measures even milliseconds with 100% accuracy. So lets implement this function to measure the time elapsed between start and stop. In this project we are using OLED display but we can even use LCD display or 7 segment displays to display the time.

Required components:

Product NameQuantityamazon logoamazon logo india
Arduino Microcontroller1
0.96" OLED display with I2C1
Tactile Push Button1
5V power supply (Micro USB or External).1
Few Connecting Wires
You can buy the required components from the given best buy links. We choose the components according to value for money.

Circuit diagram of Arduino Stopwatch with OLED display

Now connect all the required components using the below circuit diagram.

arduino stopwatch using oled display circuit diagram

You can use any Arduino microcontroller boards such as Arduino UNO, Arduino PRO mini, Arduino Mega to make this, we choose to use Arduino NANO to make the project compact and easy.

As you can see from the above circuit, OLED display power pins VCC and GND are connected 5V and GND pins of Arduino NANO. The I2C pins of OLED display SDA and SCL are connected to A4 and A5 of Arduino respectively.

Next the first pin of push button is connected to digital D6 of Arduino and second pin of push button is connected to GND pin of Arduino. Here we used push button without resistor as Arduino pins has internal pullup resistor which we can activate through the code.

If you want to use LCD display check this tutorial: Connect LCD display to Arduino

Program code for Arduino stopwatch:

After connecting everything its time to upload the Program code to Arduino using Arduino IDE, connect Arduino to a PC where Arduino IDE is installed. Choose the board as Arduino NANO or which ever you use and select the correct port from the Tools menu. Install required libraries from the built in Library manager or you can download the latest version from the below links

Required Libraries:

  • Download Adafruit_GFX library – Link
  • Download Adafruit_SSD1306 Library – Link

Next copy the below code and paste it in IDE workspace and press upload button. That’s it the code will be uploaded.

Output and testing

After uploading the code OLED display show “Press start” as shown in the below output image.

oled display stop watch output press start

Now click on the push button to start the stopwatch timer, the timer runs. To stop and check the elapsed time click the push button again, it displays the elapsed time. To reset the timer click the button again, to start again press the button again.

arduino stopwatch timer running out on oled display

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CircuitSchools Staff

We at CircuitSchools publish on basics of electronics and electric components and everything related to evolution of electrical technology with complete analysis of development boards and modules along with latest projects with innovative ideas.

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  1. Hi there iv’e built the stopwatch. circuit it works great could you tell me how to remove the RESET function as i just wats an elapsed timer thanks
    Regards Harry

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