IR Receiver PCB:
The IR Receiver PCB board is constructed on stripboard 3/4 inch wide and 1 1/2 inches long. See the circuit diagram and photographs.
Velcro mounts the PCB board to the top of the 2 x 4 upright. Using three wires of a four wire telephone cable make a connection cable to 18M2 PCB board.
Opto Sensor PCB:
The Opto Sensor PCB board is construction on a piece of stripboard 5/8 inches wide and 3 inches long. See the circuit diagram and photographs. Below is a link to the datasheet for the Opto sensor.
The Opto Sensor PCB board is attached to the main upright with Opto Sensor Mount (part H). Two #6 sheet-metal screws 1 ½” long will attach the mounting block to the upright and two #4 sheet metal screws half-inch long will attach the PCB board to the mounting block
A “sensing hole” is required in the plywood disk for the Opto sensor to detect the neck center position. Place a ruler in the mechanical jaw and rotate the neck so the ruler is horizontal, drill a 3/16” diameter a hole at the three o'clock position, see photos. Using three wires of a four wire telephone cable make a connection cable to 18M2 PCB board.