PTT foot switch for contests

I guess you can buy headsets in every computer store – headset. I made the device about five years ago, which contained an NF compressor, equalizer and roger beep. Then I solved the switching with a lever switch on the front panel. In the I. subregion I found out during the first connection, that recording connections on the computer and holding a hand microphone in the other is pure utopia.

Mentioned “snag” could be solved with a desk microphone or headset. Because of that, that I'm listening on headphones, and not the speaker, I chose the second option. But it needed better RX/TX switching. I didn't like VOX (difficult search for suitable time constants, the possibility of unwanted switching). So there was only one option left – foot switch, popularly speaking “whore”.

I found the only instructions for the construction in the Holic collection 2000 under the name “Add-on to the racing TRX” by Pep OK2SFI&OK2KVM team. “Railwayman” did not suit me from an aesthetic point of view and partially also from a functional point of view. That's why I decided on my own construction.

Cuprextite is widely used in radio technology. In addition to printed circuit boards, it is possible to easily solder a cavity from it, or an enclosure for HF circuits (lighter than sheet metal). It is enough to cut four pieces of cuprextite with sheet metal scissors and solder in the corners with a 100W soldering iron with a minimum of tin. Finally, sand a little if something sticks out and that's it. That's why I used cuprextite to make the foot switch.

Each piece will be original, therefore, the dimensions must be adapted to your needs and the material used. First if you cut (or cut) it is convenient to have all the parts for the kuprextit (hinges, spring and microswitches) prepared and adapt the dimensions to them.

It starts with precision manufacturing “ears” from thicker cuprextite. On the base sheet of cuprextite (150×100) the sidewalls are bumped into (pay attention to the squareness). Top “what?” it is necessary to make it a little wider (cca.150×104), to fit easily into the counter without rubbing the sidewalls.

Now you need to drill the holes for the hinges and install them. “U-čka” must be able to be opened and closed without any friction. The rear part with cinch connector is soldered to the lower part (in the middle) and two microswitches (by regions). They need to be fixed like this, so that they can be pressed, that is, with a slight overlap above the edge of the back wall.

The stop is defined by a screw (or better with two screws at the edges). Their length must be determined by trial and error – so that after pushing the top part, the microswitches are reliably switched on, but he doesn't crush them yet. In my case, the stroke is approx 5 mm. A steel spring can be obtained, for example, from the battery compartment of a malfunctioning electrical appliance.

It is already possible to test the switch, even use it. But it still looks clumsy. That's why I recommend the sides, spray the back panel and hinges with car spray. I used the rest with the matte black shade (I use it to spray the printed circuit board from the side of the components before installing them – it looks like UFB).

Kuprextit slips on the carpet so I took an old truck tire tube and cut a sheet of 100×150 mm, which I glued to the lower part with Chemoprene. The rubber needs to be properly sanded, then it holds perfectly. I glued sandpaper to the top (red, gross). This way the foot will definitely not slip, sandpaper wear is minimal.

The result is both aesthetic and functional. I worried about stepping on the switch for nothing. Cuprextite only slightly springs (only one microswitch turns on when the foot is placed inaccurately). Therefore, I recommend using two softer springs with two stop screws, thus eliminating this phenomenon. Maybe a reinforcement made of kuprextite strips would also help.

The construction costs in my case were around two hundred (hinges, micro switches, the rest of the black spray and the tube from the tire were at home). I just had to buy it, cinch, sandpaper and glue. The switch was completed in three afternoons.

The foot switch greatly facilitates contest operation in particular. The effort spent on its construction will return to you with the first connections.