Simple Morse Key Circuit using IC 555

This article show how to make a Simple Morse Key Circuit using IC 555.

It is an easy circuit and is good for Morse code practice.

IC 555 can work in many ways.

In this project it work as astable multivibrator.

That means it make signal by itself and there is no need for outside trigger.

Circuit Working:

Parts List:

IC 555 work as astable multivibrator.

It make high and low signals without outside trigger.

Resistor R1 and capacitor C2 control how fast it oscillate (frequency).

Change R1 or C2 to change sound tone.

Resistor R2 and C2 control how long sound stays ON and OFF (timing).

These timing make Morse code dot and dash.

When key is pressed the circuit is complete and IC 555 start to oscillate.

R2 and C2 decide how long speaker makes sound and stays silent.

Morse Key Codes:

Morse code is way to send text using short and long signals called dots and dashes or dits and dahs.

It is named after Samuel Morse who helped make early telegraph system.

Below are the morse key codes:

A: ·- B: -··· C: -·-· D: -·· E: · F: ···- G: –· H: …. I: .. J: .— K: -.- L: ··· M: — N: -. O: — P: .– Q: –.- R: .-· S: … T: – U: … V: …. W: .– X: -··- Y: -·– Z: ..–

Formulas:

We use IC 555 in astable mode for Morse key circuit.

Pressing key starts the signal and releasing stops it.

This make signal go ON and OFF again and again (oscillate).

Circuit use these formulas:

Frequency (f):

f = 1.44 / (R1 + 2R2) × C

where,

• R1 and R2 are resistors
• C is timing capacitor
• f is how fast signal go up and down

Duty Cycle D:

D = R2 / (R1 + 2R2)

D show how long signal stay high and low

Change R1, R2, C to set tone and timing we want.

How to Build:

To build a Simple Morse Key Circuit using IC 555 we need to follow the below mentioned steps:

• Collect all parts like in circuit diagram.
• Pin 1 of IC 555 goes to ground.
• Pin 2 connect to pin 6.
• Capacitor C2 connect to ground from pin 2 and pin 6.
• Pin 3 connect to ground through capacitor C1 and 8 ohm speaker.
• Pin 4 connect to +6V power.
• Pin 6 again connect to pin 2.
• Resistor R2 go between pin 6 and pin 7.
• Pin 7 connect to +6V through resistor R1.
• Pin 8 connect to +6V.
• Morse key connect to +6V line.

Conclusion:

Making Simple Morse Key Circuit using IC 555 is fun and good learning.

We can build safely and enjoy sending Morse messages with this simple project.

References:

Morse code