HFN (Hands Free Nanokeyer)

by Mikel EA2CW

version 1

version 2

LAST version 3

When conducting SOTA CW activations, and after almost 300 made since 2013, I’ve found very useful having both hands free to write down the log. Along this time I’ve been searching some kind of keyer which fills it.

Some time ago, I purchased a WWII tank vertical keyer which could be tied to the leg and found this way very interesting: It leaves your hands free, you have the keyer in a comfortable position to operate and it will never be out of place, forgotten out of sight or stepped on.

Later I was able to convince Andres EA3PP to make a keyer combining not only his very good mechanical system but also fitting the following conditions: Small enough to be used/carried portable, light weighted, and somehow tied to the leg. It showed to be what I’ve been pursuing!

Last year (2018) my son purchased a 3D printer and it opened me a world of applications to my hobby! dipole centers, insulators, wirewinders, guying rings and, finally, a fitted-to-myself paddles. A lot of hours of design, some no so convincing prototypes, buying materials to the asian giants and here is it, the Hands Free Nanokeyer (HFN for short), fullfilling all my specs, and ready to be carried with my portable radio sets: Elecraft KX2, QCX mini 30m, and Venus SW-3B.

So, here I would like to present it to you with the only goal of encorage you to build and use it. I hope you will do, and enjoy it during your portable operations (SOTA, POTA, VGD, WWFF, ...)

Well, let’s start working!

First of all you need to have a 3D printer (or a friend who has it as alternative). Part of the research while designing it was to find the best compromise of strength and, at the same time, flexibility of the paddles. The material used is PLA and probably you will realize that the paddles are a bit thinner in their back part. That is to allow them to have the perfect touch. The distance to the center is fixed: not too large, but wide enough to avoid accidental keying.

List of materials:

- Obviously, the > 3D model STL file (ver.1) < or > 3D model STL file (ver.2) < compatible with most 3D printer software. It is made on two parts to meet printer needs. As said, the material used is PLA

- Some screws (5) and nuts (3) of Metric 2

- 1 x M2 spacer 10mm long (I used the type which has hole in one side and thread in the other. Both sides holed can be used too, but you will need one more screw).

- Approx 50 cm of 3 conductors wire and 3.5 mm stereo jack male.

- About 50 cm of 20mm wide nylon strap.

- 20mm wide zip + buckle.

Version vs Version 2:

- On version 2, the nylon strap & buckles have been replaced with a smaller, lighter and cheaper 45m velcro strap).

- Now the strap goes over the keyer, achieving a better fitting to the leg.

- The base "wings" are taller and stronger, as now the holes go at the floor and no more at the sides.

- The paddles are shorter, making the keyer even more compact.

Version 3 differences:

The design of version 3 is greatly different from the previous ones. The use of neodymium magnets means no more paddle flexure, but also a bit more complicated design.
Please go HERE to view the details, materials and download de STL file of this version.