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.

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.