Morse Code Wireless Transmitter

Morse code was one early technique for communication wherein words were sent over copper wires by tapping on a switch that connected and disconnected the wire between transmitter and receiver. The encoding was done such that each alphabets had certain combination of taps. But not only wire but also the Morse code works equally with wireless sound. Below is a schematic of such a system that can send Morse code wirelessly drawn with Proteus Professional 8.

Fig: Morse Code Wireless Transmitter

Powered by a 6V battery and using two transistors(BC558 and BC548) forming a directly coupled amplifier with some resistors and capacitors, and a switch and a loudspeaker the circuit can be used for sending Morse Coded information wirelessly.

The components used are as follows-

Category	Quantity	References	Value	Stock Code
Capacitors	1	C1	0.047u	Digikey 311-1046-1-ND
Resistors	1	R1	10K	Digikey P10KETR-ND
Resistors	1	R2	1.0K	Digikey P1.0KVCT-ND
Transistors	1	Q1	BC558
Transistors	1	Q2	BC548
Miscellaneous	1	B1	+6V
Miscellaneous	1	LS1	SPEAKER
Miscellaneous	1	RV1	100K	Digikey 3009P-104LF-ND

By the way this BOM was generated by Proteus 8 which is a new feature in Proteus 8.

In the schematic Morse code can be sent by switching on and off the switch. This will set up the signal path and we should hear the sound from the loudspeaker.

Let's check it via simulation. To do this we connect an oscilloscope as shown below-