Picture of LaunchPad Serial Morse Transmitter
Inspired by this, I decided to build a morse transmitter and add some cool features to it.

This project show how to build a little morse transmitter using an MSP430G2231 MCU.
The device can transmit in two modes:
   - serial, getting the characters from a COM port  and translating them into morse code; 
   - manual, using the key switch.

In serial mode, one character at a time is read from the COM port and transmitted as morse at 15 WPM. To better understand how morse code works, read this .

Morse keying is achieved toggling an output pin connected to the oscillator power pin, thus getting a pure CW mode.

The device is powered with 2xAA batteries, and the power consumption is kept to a minimum thanks to the Low Power Mode when not transmitting. You may add a second 4xAA supply for the octal buffer in order to increase RF power.

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Step 1: BOM & Tools needed

Here's what you'll need to build this project:

  - 1x MSP430G2231 Texas Instruments MCU
- 1x 74HC240 Octal buffer
- 1x Oscillator (operating frequency should be in the 10/12m CW band (24/28 MHz))
- 2x 220 ohm resistors
- 2x 1 kohm resistors
- 2x LED (different colors are better)
- 2 push-buttons (included in the Launchpad, you may want to use a better switch for morse keying)
- 2 AA batteries (you may want to use a separate 6V (4AA) supply for 74HC240)
- 1m electrical wire (9 AWG)

- soldering iron
- solder
- wire stripper
- breadboard or stripboard
- TI's Launchpad board
- mini-usb cable
RayBurne2 years ago
"The hard part came when I needed to build a lookup table for the morse code, as there's no known algorithm capable of encoding a character directly into morse."

Not true anymore!  Magic Morse provides encoding and decoding capability.  



Ray Burne
Matz3 years ago
Nice job! I'm just starting out with the Launchpad and have found your Instructable to be quite informative.
jbiggs124 years ago
any news on a receiver? :)
js123454 years ago
This transmitter is not legal without an output filter. Please do not put this on the air without a proper output filter. This will transmit harmonics much higher than allowed by law.

Here are example filters:
rct4 years ago
If you watch the video, start with your audio turned way down, there is a loud noise at the very beginning.
rct4 years ago
Isn't the 74HC240 Octal buffer just turning the (sine wave) output of the oscillator into an amplified square wave?
I thought of something on these lines for this contest as well... nice 1 though...