This is my first attempt to capture the schematic using Eagle. I welcome any constructive input on how to improve. I'm using a 12VDC power supply and limiting the current to the sounder using a trimpot. I selected a trimpot so that I can adjust to any sounder since they have varying resistance. I put the Keyer in the same loop as the digital signal so that I can drive the sounder with either an arduino/rpi or with the keyer. I used a 5v voltage regulator to limit the voltage on the bus since it's connected to the microcontroller board. I probably need a diode there, but I have an idea I want to explore, which is to have the wire going to the microcontroller to be used to send commands back to the board.