I would like to introduce you to my latest homebrew project. A contactless cw paddle for less than 10 euros.
The circuit requires two contacts each, which are connected by the skin resistance. Since I hold the key in my hand while keying on the summit and touch one contact, touching the second contact is sufficient. If you have very dry skin, some saliva or a higher summit will help.
I get the operating voltage of the circuit from the trx, because the current devices have a switching voltage of 3.3-5V at the key input. This voltage switches the transistor through when touched and the symbol is sent. The capacitor C7 (why not C3 ) holds the charge even when keying and R1C1 / R2C2 block the RF.
I have built my version of this little critter and it works!
I will take it to the summits and test it in the field. I have my doubts that it will key reliable in cold or rainy weather, but let’s see! I will report back. It definitely needs some spit on the finger tips to key accurately.
The big advantage of this design is that it runs without a battery. One item less that can fail. It is also light weight. If I stick with this keyer I would build another one with smaller resistors (the 22MOhm are 5W), eventually with SMD components to see how light it can get.
Hello Chris,
Thank you for sharing the circurit-design. Now I Have build my own touch-
paddel, work’s fine on every rig and keyer I have. It is the first build and I try
to build a premium version soon. It’s ideal for portabel OP’s and weight is
only 17-18 gramms. I will do some heavy weather testing(Rain,snow and
cold)to see, if it works under bad conditions. But up to now it’s perfekt for
me, without a Battery that’s the best…
Hello Chris,
Yes, I have got the same disease, now I have a correct diagnosis. What a laugh, change key’s won’t help in my opinion, but I carry always a spare key in
my pack. Few years ago I build a singlepaddel from bicylespokes(I am a cylist all my live), once adjustet work’s very fine. I show you my keys for outdoor use.
By the way, your guitarplaying on a song for guru, was very good. I like your
Improvisations and the feeling, that reached me.
I’m one of those with a very dry skin and after trying one of those several years ago, I found these type of paddles don’t work for me, so I’ll keep using my Palm paddle or some of my homebrewed ones with metal-to-metal electrical contacts.
The use of saliva on my keying fingers is something I don’t want to do or depend on.
But I’m glad it works for you and others. I wish you a good success and lots of SOTA QSOs with it.
Thanks for sharing your project here.
73,
The recent versions designed by VK3IL are based on detecting even very low levels of pressure on the paddle, not capacitance or conductance via moisture on the fingers. I have my kit waiting to be built and will let you know how it goes.
I was able to improve my contactless key with. A small lithium button cell has significantly improved the sensitivity. The current through the battery is in the range of 0.0001 mA and should last for decades.
Here is a size comparison. Sometimes I miss the cheat sheet on the PalmPaddle.
73 Chris
) holds the charge even when keying and R1C1 / R2C2 block the RF.
.
