Simple Stopwatch Project Using 555 IC

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In this project, we are making a Simple Stopwatch project. If you are a beginner and looking for an easy project then this is a perfect project for you, and it has a lot of uses and applications as well. This circuit is simple and inexpensive as it is using only a few parts that are, a 555 timer IC, photocoupler, calculator, and a few other discreet components.

The purpose of this circuit is to provide a stopwatch, even though they are available ready to use but it’s fun to make it by yourself for learning and experimenting.

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Hardware Components

The following components are required to make Stopwatch Circuit

S.no	Component	Value	Qty
1.	Input Supply DC	5-12V	1
2.	IC	NE555 Timer	1
3.	Photocoupler	PC817	1
4.	Calculator	Simple	1
5.	Resistor	4.7KΩ, 1KΩ	1, 1
6.	Potentiometer	100KΩ	1
7.	Electrolytic Capacitor	10µF/10V	1
8.	Switch	Push button	1
9.	Ceramic Capacitor	0.01µF	1

NE555 IC Pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of 555 Timer

Stopwatch Circuit

Working Explanation

The operating voltage of this circuit is 5 to 12 volts DC. Switch S1 is used to operate the stopwatch, any type of switch can be used here that is suitable to you. A 100K variable resistor is used to adjust the speed of the numbers in the calculator. A 555 timer IC is used to provide oscillations in the circuit. The result is displayed on the calculator.

After finishing the circuit connect the power supply and press 0+1 on the calculator. On pressing 0+1 on the calculator and then = again and again, the calculator gives a sequential output I.e., 1,2,3,4. But in this circuit, the 555 timer IC does this automatically. Make sure to enclose this circuit in a suitable enclosure with the batteries so that it is portable.

You can replace the NE555 IC with a 7555 timer to operate this circuit with lower voltages like 3 volts.