Electronic Design

Prototyping Electronic Circuits The EZ Way

SchmartBoard has announced that patent 7,511,228 has been granted for the company’s “EZ” technology for hand-soldering surface-mount technology (SMT) electronic components (see the figure). This brought to mind a SchmartBoard demo I once participated in at an EDS trade show.

The company was betting that anyone could solder a tiny chip to a board in a matter of seconds with its new technique. I’m proficient at soldering and know enough to make sure I haven’t created a “cold” solder joint. Soldering a tiny chip like the one the company’s representatives gave me looked challenging, though.

However, they said the board had special grooves that would let the solder flow to exactly the pins where it was needed. Sure enough, I applied the heat and the chip was soldered to the board in a matter of seconds, with no muss, no fuss.

Thinking about this patent made me think of the first SchmartBoard I had ever seen—before the company invented this unique system. I liked its prototyping ideas, since it takes some ingenuity to improve on past methods. SchmartBoard has a modular approach that can be used to create different parts of a circuit with different kinds of boards that it sells. The boards are small, but can be fit together to build a larger circuit. It’s a nifty idea.

Thinking about SchmartBoard reminded me of when I built circuits on the solderless breadboards that are still popular today. I was working for an enthusiast publication and a reader questioned why a particular “tornado warning” circuit didn’t work as published.

I sat down and built the circuit from scratch on a small breadboard, since I couldn’t detect the problem from the circuit diagram itself. After I built it, I realized that the reader was correct. But the act of building the circuit gave me further insight into the design and I was able to see where the problem lay.

The invention of the solderless breadboard was a significant step over some of the other prototyping methods I used growing up. One was the Radio Shack 100 Electronic Experiments, I think it was called, which employed springs to essentially create a pointto- point wiring system. This method seemed overly cumbersome to me, since adding two or more wires to a single spring was a chore.

Yet it seemed to be an improvement on the basic point-to-point wiring that I used when I was a kid. The first electronic circuit I ever built was a game I created in the fourth grade with one set of questions on one side, the answers all mixed up on the other side, and a buzzer to indicate a correct answer.

My wiring technique for that game was a dry cell for a battery, which had screws to connect wires to it, and metal fasteners like you might see holding together a bunch of sheets of three-hole paper. You could easily connect wires from the battery to the fasteners and change them up so users didn’t get used to the hard-wired connections.

One prototyping method that was in vogue for a time, but I don’t see much of today, is wire wrapping. It was a big investment in tools and wire and took some skill to accomplish. I never tried it myself, but I have used some printed-circuit boards (PCBs) that had been prototyped this way. I also owned some of the wire-wrap sockets that were popular at the time with the extra-long leads.

The only other prototyping method I can think of involves the proto boards that electronics professionals and enthusiasts probably still use today, since companies are still selling them. They weren’t a favorite of mine, since I tended to build smaller projects.

I still remember the first kit I built, which was a transistor radio. It used point-to-point wiring, and I built it like I had built plastic models of cars and airplanes before that—just follow the instructions until you’re finished. I found out then that electronics was different, since the radio didn’t work. I then had to go back and try to figure out the problem.

At the age I was, I couldn’t solve it on my own. But my uncle came to the rescue, diagnosing a capacitor that I had soldered in the wrong direction. I wish I had kept that kit. It would have been fun to check out my prototyping abilities after all these years.

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