The personal website of Scott W Harden
Source code for Code Practice Oscillator and Keyer
---
title: Code Practice Oscillator and Keyer
date: 2009-04-20 14:20:00
  - amateur radio
  - old
---

# Code Practice Oscillator and Keyer

__Over the last couple weeks whenever I had the time__ I'd work on creating a little Morse code keyer. After a few different designs I came up with the winner. Basically it just uses a bar of aluminum which rocks on a metal pin. Thumb-screws on each side of the balance point (fulcrum?) can be adjusted to modulate the distance the paddle has to go down to be activated, and how high the paddle goes up when released. A couple springs (one pull-type and one push-type) help give it a good bounce between keys. Two knobs control volume and frequency. I especially like the ability to control the frequency! A capacitor inline with the speaker helps smooth the output a bit too. It's not professional, but hey - for a couple bucks of parts I made a functional keyer and had fun doing it. Now I guess I should put more time into learning Morse code...

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[![](img_1535-500x375.jpg)](img_1535.jpg)
[![](img_1537-500x375.jpg)](img_1537.jpg)
[![](img_1538-500x375.jpg)](img_1538.jpg)

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<blockquote class="wp-block-quote"><p><strong>Thoughts from future Scott (August 2019, ten years later)</strong></p><p>Wow this is rough! I'm 90% sure this is based on a 555 circuit. lol @ the use of Jenga blocks. It looks like the wire was sourced from cat5 cable. That aluminum slab later became the base and heat sink for an IRF510-based push-pull amplifier.</p></blockquote>
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