The PCB is designed with wide traces to allow easy fabrication from double-sided copper PCB blanks using a milling machine; alternatively PCB fabrication may be outsourced to a PCB service provider using the provided Gerber files. The locations, orientations and values of the components are shown in Fig. . A complete circuit diagram is provided in Fig. . All components other than the OPT101 amplified photodiode are soldered directly to the board; the OPT101 is mounted in an 8-pin DIP socket to simplify final assembly. The MCP602 and TC7660 may also be mounted in sockets, but this is not necessary. ~10 cm leads connect the LED to the terminal block on the PCB.