Prototypes are not just a vital element of the electronics design but a powerful tool for public communication and exhibition too. Creating a physical mock-up of an object makes it possible to understand the ways people will attempt to interact with it, and the ways it can be manipulated. Concisely, in the electronics design and development process, prototypes can be used for different purposes including experimentation, learning, testing, proofing communication and interaction.
Today, designers and DIY practitioners are using various prototyping ideas to express their concepts of electronic artefacts. These prototypes are generally constructed using various solder and/or solder-free methods. All of these methods have their own pros and cons:
Wire-wrapping and point-to-point wiring. In wire-wrapping method, fie wire is tightly connected to endpoints by wrapping onto a rectangular pin—instead of soldering—with the help of a special gun tool.
Fig. 1: Wire wrapping and point-to-point wiring
In point-to-point wiring, components are soldered to a perforated board, also known as Vero board.
Both wire wrapping and point-to-point methods are inexpensive, but wire wrapping allows reliable connections to square leads only. So it becomes necessary to solder discrete components to a header that goes into an IC socket or to individual wire-wrap pin. With point-to-point wiring, it is easy to simply twist, solder leads and run wires where needed. However, this method is slow and requires ample skill.
Solderless wiring. The invention of the solderless breadboard—an improvement over the basic wire-wrapping and point-to-point wiring—was a signifcant step over many of the other prototyping methods. Breadboard is a quick way to set up any circuit using standard through-hole components. But breadboards are not good for high-frequency circuits due to stray capacitance and inductance. Further, these are not suitable for high-voltage and/or high-current circuits. Although breadboard is an essential facet of the design process, the reliability and endurance of breadboard-based prototypes have been a big problem.
Fig. 2: Solderless breadboard
Printed circuit board wiring. Using printed circuit board (PCB) is a costlier but reliable method of prototyping electronic circuits. The most common PCB type widely used for hobby prototyping is the generic PCB, which has a pattern of holes and connections (multiple holes per pad) similar to a solderless breadboard.
Generic PCBs are easier to use than plain perforated boards, especially for IC-based circuits. But layout constraints are a minor drawback and prototyping may be much more difficult.
Fig. 3: Generic PCB
The ‘real’ PCB (which can handle virtually any component and power level) used ubiquitously in the production of electronics is inappropriate for low-budget basic prototyping, because laying out the customised PCB and getting it fabricated may take time. Besides, it is very difficult to make changes or modications in the initial circuit structure after finishing the prototype.
Using surface-mount devices (SMDs) instead of the traditional through-hole components makes a prototype more compact. The PCB layout becomes easier because different things can be done on each side. At the same time, prototyping becomes much more difficult(requires high soldering skill), which calls for the use of special SMD prototyping boards/custom PCBs and handling/soldering tools.