Single Lever Morse Code Paddle / CW Cootie Key

BACKGROUND: 

After designing a super simple iambic paddle for portable ops, I had multiple requests for a single lever version.  So, here it is.   

I added a small snap-on cover to the design, but it's not entirely necessary.  The hole in the tip of the cover allows you to mount the cover on the back of the paddle while in use with the cable attached through the hole. 

Parts are kept to a minimum, and total cost per unit for a batch of 10 is less than $2 each, just like the other paddle!  At 58 x 20 x 19 mm (2 x .8 x 0.75 in.), this little guy won't take up much space in your pack, but functions like a much bigger unit.  Set screws allow adjustment of the throw, but tension is not adjustable.  Still, the feel is very good.  The 3.5mm TRS jack allows connection to your radio with any standard Aux cable.  Want to add a magnetic base?  Stick three or four neodymium magnets to the base with super glue. 

BILL OF MATERIALS:

Links are Amazon Affiliate links - It costs you nothing more, but I get a few cents on the dollar from Amazon if you purchase through these links. 

TOOLS:

• 3d Printer capable of printing PETG
• 1.5 mm hex driver (https://amzn.to/3gX4sB8 or https://amzn.to/3ulV3X1)
• #1 Phillips head screwdriver (https://amzn.to/3HaQlD2)
• Tweezers (https://amzn.to/3BaOeex)
• Wire cutters or scissors you aren't worried about damaging (https://amzn.to/3VycZJK) 
• Soldering iron (optional - you can build the paddle without this) (https://amzn.to/3P3bxgk)

ASSEMBLY: 

1.) Print all the things.

I've included the GCode I use on a Prusa i3 Mk ii if you want to just download and hit “print.”

Print your parts for the assembly.  Use PETG only!  This design relies on the flexibility and elastic deformation capability of PETG.  PLA will not work. 

I recommend printing the Cover on it's flat side with supports under the clip part.  I just set parameters for effective bridging of the top cover portion.  Alternatively, this can be printed with the wide opening down with some supports.  

You may need to clean up the openings of the bottom holes on the paddle levers if your first layer height results in some elephant's foot spreading.  Also ensure the small “spring” levers on the bottom of the lever assembly are not bound to the outer levers. 

2.) Attach 1" of wire to each of the side lugs of the 3.5 mm jack.  

Do not attach wire to the ground (center) lug. 

Use 30 ga or smaller wire.  Thicker wire will affect the paddle feel. 

Ideally use steel or copper clad steel wire for durability.  Magnet wire may work well enough, and the threads on the set screws will cut into the enamel to make electrical contact.  I like NiChrome wire because it is solderable, but very cut resistant. 

If you don't have a soldering iron, twist the wire onto the lug, securing it through the hole, then wrap the wire tightly around the lug a few times before passing the wire through the hole one final time.  This provides sufficient electrical connection without requiring solder.  This can also allow the use of stainless steel wire. 

3.) Install the 3.5 mm jack into the Lever print. 

Insert the 3.5 mm jack into the center of the levers and secure through the larger hole with the nut that came with the jack. 

Orient the jack with the ground lug centered and toward the bottom.  This lug will get pinched between the machine screw and the plastic post it screws into on the base.

5.) Snap the Lever print onto the Base.

If you encounter resistance, stop and carefully clean up the openings of the holes to ensure they are the proper size. 

6.) Install the machine screw ground post. 

Use a phillips head screwdriver to secure the machine screw to the center ground post of the Lever print.  Pinch the ground lug of the 3.5 mm jack under the screw. 

7.) Insert the wires into the holes in the Levers. 

Stick the wires out through the holes in the levers.  Leave a mm or two of slack on the inside to allow the levers to move slightly.

8.) Install the set screws.

Install the set screws, ensuring the set screws pinch the wires you inserted into the holes, securing them mechanically and making electrical contact.  Screw in the set screws until they are about flush with the outer surface of the lever. 

9.) Snap on the top cover.

The top cover is symmetric front to back, so simply snap it into place. 

10.) Adjust the paddle for optimal feel. 

Adjust the paddle throw by adjusting the set screws. 

Get on the air and have some fun!

THANKS:

Thanks for building this paddle.  I hope to get you in the log some time while you're using it. 

This is an early draft of this paddle. If you have any comments or feedback on how I can make this thing even better, please let me know.  I'd love to hear it.