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Homebrew touch paddle for less then 10€

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. :sweat_smile:

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 :face_with_raised_eyebrow:) holds the charge even when keying and R1C1 / R2C2 block the RF.

73 Chris


Very clever Chris. I would like to try one of those please. Do you have an online shop etc.
Best 73

Unfortunately nothing like that.
73 Chris

1 Like

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.

Nice project!

73 Heinz


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…

73 Thomas DD4EA