Will you connect this to a or an older tube rig ? Share public link
Static filled the room.
The schematic can be expanded with various modules depending on the builder's requirements:
To the uninitiated, a schematic looks like a plate of spaghetti. To a ham, it’s a map. But Elias had been depending on online "how-to" guides and forums, blindly copying pin connections without understanding why . He decided to strip it back to basics and actually read the schematic as if it were a story. k3ng keyer schematic
This wasn't just a switch; it was a safety barrier. The schematic was telling him: "Do not connect the delicate 5-volt microcontroller directly to a 300-volt tube rig. Use the optocoupler, or you will fry your board."
The schematic uses an NPN transistor (like the 2N2222 or PN2222) or an N-channel MOSFET (like the BS170).
Elias rummaged through the drawer, pushing aside ancient crystals and strange connectors, until his fingers brushed a small, blue circuit board. An Arduino Nano, still in its anti-static bag. Will you connect this to a or an older tube rig
Silas shuffled forward, his leather apron creaking. He peered at the schematic printout Elias had taped to the wall. It was a convoluted mess of logic gates and discrete components, drawn on the back of a pizza flyer.
Drive the internal LED from an Arduino digital pin (typically D11 or D12) through a current-limiting resistor to GND.
Keep the analog potentiometer and paddle lines as short as possible to minimize RF pickup. To a ham, it’s a map
(I²C to save pins)
If your rig does not have a built-in sidetone, or you want to practice offline, the K3NG code features an audio output pin.
Sidetone (audio)