Actually, it is (or at least, WAS) sold commercially.
https://www.eham.net/reviews/view-product?id=552
I can’t remember where or when I got mine - possibly at the Dayton Hamfest in 1999? The links I’ve found for it don’t appear to work. Construction involves gluing strips of thin brass for the contacts.
…watch out - if you follow the links it will lead you to a x rated site
That particular link doesn’t, but some of the links on the page may do so.
A bulldog clip paddle using a small block of wood and some copper strap and buttons… that’s the kind of genius household inventiveness I’m used to seeing on VK3YE Peter Parker’s Youtube channel!
…just checked again, the link for “..more information” is to the x rated site
It’s actually a very ingenious design and very practical 
It took a whole day to think about Bulldog! How does it work?
It took only 10mn to build it !!!
Watch “Dingo CW key” on YouTube
Not having built the original, I couldn’t figure out how the straight key worked. Now that I see the 45 degree bevel (which was visible in my photo, if I had compared it to an unmodified clip) it all makes sense.
Now I’ll add the Bulldog straight key to my list of projects…
I attach the keyer cord to one of the handles on the second binder clip for strain relief. (My rigs have their keyer jacks on the back panel, so a direct mount doesn’t work well.)
Hi Dale,
Kapton tape as insulator and gold pins soldered on Cu foil substrate.
Edit: I lubricate the beveled hinge with Vaseline for rust protection.
Hello. Regarding the sensor key, I liked the idea of a portable CW transmitter and decided to build one out of a USDX-Mikron. For ease of use, I decided to equip the transmitter with sensor contacts. I couldn’t find much information on this topic and decided to build it intuitively. The result is an EMI-resistant design with three levels of protection.Additionally, a current balun was installed after the tuner. Easily accessible components were used. Tested on various antenna types, shortened and full-size, and at various frequencies, no operational errors were found.
The device was installed in a modified Mikron case. It turned out to be a very convenient device. I hope my findings are useful!
Happy New Year,
Few details about my tiny QRP radio based on the work of PE1NNZ, a magician in SDR!
