K3ng - Keyer Schematic

Symptom: The LCD powers on, but you see black boxes or nothing. Cause: You connected the LCD's V0 (contrast) pin to ground. The schematic shows a between GND and +5V, with the wiper going to V0. Fix: Build the pot circuit. You need variable resistance to set the contrast.

Put a red box around pins 20 & 21. You don't need them for basic functionality. k3ng keyer schematic

In the firmware, you map:

Because the code runs on an Arduino, the schematic is simply the wiring map to unlock these features. You can build a minimal keyer with three wires, or a deluxe command station with 40 components. The schematic scales with you. Symptom: The LCD powers on, but you see