Because our own Mr. Steinson would not claim the credit for himself, I give to you the ‘Steinson Circuit Board’; a circuit board made with a 3D printer using ABS plastic.
For size reference, a U.S. quarter is just slightly smaller than the square. To complete it a resistor, amplifier IC (placed on the opposite side of board), and connecting wires are inserted into slots and holes in the plastic board, making a perfectly working circuit. While it may look particularly shiny, no glues, conductive paints, or other materials were used to fasten the wires and connectors. The pins for the amplifier are simply bent, as are the leads for the resistor. Wires are ‘hammered’ in place with a small awl. Once put together, the wires and components are surprisingly secure. In some ways the board offers more protection than a typically soldered PCB. Not shown in the picture above is a small cover and clamp that prevents accidental shorts (such as by laying the board on a conductive surface) and further secures the wires and components.
It might seem that we used a new tool to do something that can be better accomplished with other approaches. For the MMA weather station project, however, we dreaded the idea of designing and ordering custom PCBs, as this would undermine the whole idea of bypassing mass-production in favor of local fabrication and eventual customization. A small CNC router could make PCBs, but small boards are difficult to build, and it added another tool and level of complexity to the project. Again, the point of the MMA is to move fabrication and eventual design of weather stations to developing countries. Similarly, the thought of etching a PCB with chemicals was unattractive given the skills necessary, likely scarcity of the materials needed in our envisioned project locations, and some danger / hazard to the maker. Of course solder boards are available, but then too we would need to supply boards externally, as well as introduce new skills and tools.
Most of the circuits on the weather station are very simple; typically consisting of a sensor, amplifier, resistor and then points for power and read out. Few of the sensors the project has considered are ICs, and for now at least there are no SMD components. The only chips in use are the amplifiers and clock timers. Everything then hooks up to a micro-processor, such as an Arduino. While the 3D printed plastic circuit is not for every application, the ability to do so makes the stations considerably more simple and inexpensive to fabricate. It also makes the overall project simpler, by not necessitating additional tools and methods to address one specific component.