Careful planning is required when building a pedal. Every pedal uses different electronic components arranged to create a certain type of effect, such as a delay or "wah-wah." In addition to planning the electronics, designers determine how wide, tall and long the pedal needs to be to accommodate the electronics, switches and user interface, which may include LEDs that show which state the pedal is in.
You cannot build a pedal without a schematic. A schematic shows you which electronic components are required to build the effect and how to arrange them. Companies hire electronic experts to create and test their schematics. Hobbyists typically use schematics found in books or online. Hobbyists with an advanced knowledge of electronics modify existing schematics or create their own. The schematic is transformed into a blueprint of where the electronics will be placed on an actual circuit board. Professionals use custom printed circuit boards, PCBs, to lay out the electronics in an efficient and space-saving manner. Hobbyists use perf boards --- prototyping circuit boards with pre-drilled holes --- or etch custom PCBs.
A pedal's enclosure houses all of the electronic components and power supply. Enclosures are typically made of metals, such as steel and aluminum, but some are made from plastic. Pedal manufacturers typically make their enclosures using high-tech machining equipment, such as precision-press brakes, which shape the metal. Holes of varying sizes are drilled into the enclosure to accommodate switches, potentiometers, sockets and other components that are accessed externally. Holes may be drilled using a drill press, which is more efficient than a handheld drill. Hobbyists typically purchase multipurpose enclosures and customize them with a handheld drill.
Before a pedal leaves the factory, professional engineers run quality control tests. Engineers run audio test signals from computers and hardware waveform generators through the pedal. The signal is observed on an oscilloscope or a computer to see if the signal is being modified properly. Engineers also listen to the resulting sound. Hobbyists test pedals by listening to their output or observing the audio signal on a hardware or software oscilloscope.
The designs on retail pedals, such as company logos and artwork, are screen printed onto the enclosure using special inks for metals. Some enclosures are painted by hand. Hobbyists paint the enclosures by hand or use printable stickers.