Building the K3NG Keyer requires basic electronics skills and knowledge of soldering. The keyer can be built on a breadboard or a PCB (Printed Circuit Board).
Build the transmitter keying stage. For the nKeyer, Q1 (2N2222) is used for key line 1. Connect: k3ng keyer schematic
A KY-040 or generic encoder is a huge upgrade. Looking at the schematic: Building the K3NG Keyer requires basic electronics skills
For those seeking a more defined path, the project by N7XG offers a fantastic, ready-to-use schematic and PCB. This popular variant is built around an Arduino Nano 3.0 and includes a 5V Mini-360 buck regulator for power input, LEDs, headers, and built-in transistor drivers for keying. The full schematic is available in its manual. The parts list from the nKeyer gives specific values that are a great starting point for understanding the component requirements of a K3NG keyer. For the nKeyer, Q1 (2N2222) is used for key line 1
A 3.5mm mono jack connected to the drain (for MOSFET) or collector (for BJT) of the transistor. 4. Optional but Recommended Features
Connect Pin 2 (Cathode) of the optocoupler to Arduino Ground.