Learning to crawl

I had an interest in electronics since I was very young. I would often take apart appliances to find out what was inside. I thought I might be able figure out how they worked. My mother wasn't very happy about that.

Electric motors were really interesting. I tried to make toy motors work, but I didn't even know enough about current flow and insulated wires to make that happen. I tried to build my own motors, sometimes it worked, sometimes it didn't. Years later, I realized I had overlooked the angle between the brushes and the field magnets. A minor yet critical detail.

Idle hands

When I was seventh grade, a friend purchased a gag joke book that produced a mild electric shock when it was opened. I was totally amazed at how it worked -- basically a mechanical vibrator interrupting a small transformer. I soon found that transformers commonly used in low voltage adapters could do the same thing. We built mild shockers using these transformers wired to a battery. My seventh grade science teacher wasn't happy about it and confiscated one of my devices. I think it annoyed him because he didn't understand how it worked and thought it might be dangerous.

We also played with automotive ignition coils quite a bit. We tried to get the largest spark we could out of a coil, a lantern battery, and motor as an interrupter. I didn't completely understand how it worked at the time, so I had mediocre, but interesting results. Years later, armed with more theory, I built high voltage capacitor discharge circuits that pushed common ignition coils to their limits. I was able to achieve up two inch sparks from a pair of coils.

I had progressed to taking apart television sets. Lots of interesting goodies were in there, but it was largely a curiosity. Years later, a college friend used "number of TVs disassembled" as a figure of merit. Funny how interests converge.

In 1979, I saw a TV advertisement for a programmable robot tank-like toy called the Big Trak. It had a simple numeric keypad for programming forward, backward, and turning motions. I was totally transfixed, it was incredibly amazing! The idea of a machine operating under programmed computer control was like rocket science at the time. I asked my parents if they could buy one for me, but it cost about $45. That was quite expensive for a toy in those days, so my mother wasn't inclined to buy it. My mother then did something that was far more profound. She told me that I should be designing building something like the Big Trak, not not buying a fully assembled toy. I was intrigued, it made me think in ways I had never considered. In retrospect, my mother did me a great favor by not buying that Big Trak.

Years later, I would design, build, and program machines far more sophisticated than the Big Trak. Some are in Earth orbit.

Transistors

In high school I started building simple transistor circuits to flash lights on and off. My mother was taking a college course on computer archicture at the same time. She explained some of the basics of logic gates, flip-flops, and counters. TTL was the dominant logic family at the time and Radio Shack had an ample supply. I improved my flashing circuits with sequencers using counters and gates. It was great fun. I didn't have the formal education then, but I was reproducing much of the fundamentals behind finite state machines.

Microprocessors were really taking off at that time. I have fond memories of wire wrapping a Z80 based microcomputer with my brother and a friend. I don't think we ever finished it, but the idea that we could do it was an achievement in itself.

Still, my teachers were not impressed. They considered my interest, and the circuits I would bring to school, a distraction. I guess they had nothing constructive to say about it.

I convinced my parents to buy me an oscilloscope. Nothing fancy, just an old Tektronix 515A for $125. Tragically, it stopped working a few days after I brought it home. The small electronics shop I bought it from wouldn't take it back. I spent a week tracking down the problem: a shorted filter capacitor in the high voltage supply. Fixing that scope was yet another learning experience, it taught me valuable problem solving skills.

The scope wasn't fast or light, but I spent countless hours building circuits with it. I rarely built anything of practical value. The process of engineering and discovery was more interesting than the goal, I guess. That old 515A is in my basement gathering dust. I'm not sure if it works any more, but I keep it to remind me of a long lost age.

More than a hobby

In college I got a part time job as a research assistant at the high energy physics lab. My first assignment was to build a high voltage pulse generator. It was supposed to produce a 50 nanosecond, 5 kiloVolt pulse increasing as square function of time. This was a tall order, but it was an interesting challenge. I used a Krytron coupled to a pulse forming transmission line.

The transmission line had a specific exponential taper which was a challenge to construct. Fortunately, there was a numerically controlled milling machine available at the mechanical development shop in the Physics department. I wrote a C program on a VAX 11 to generate points to guide an end mill to cut a thin copper sheet to the exact specifications. I never achieved the exact square function required, but the experience taught me a lot about high speed circuits and pulse forming networks. I had fun programming the milling machine also.

Years later, the movie Frantic starring Harrison Ford revolved around a nuclear triggering device. The device was a Krytron, similar to the ones I used in the pulse generator. I think it was a KN-6 with integral trigger transformer. Incidentally, severe restrictions were placed on the number of Krytrons one organizations could buy at a time. If you can't build a low jitter, high speed trigger, you can't certain types of nuclear bombs.

I also built a number of circuits for computer control and data acquisition. I built lots of stepper motor controllers that manipulated micrometers and other actuators. The most impressive circuit was a frame grabber for a low light level CCD camera. CCDs were just being introduced at that time, Vidicons still dominated the consumer and industrial market.

Real time frame grabbers were not available off the shelf at the time, so I built one. I used an Analog Devices flash converter dumping it's data into a bank of static memory. The video data was read out by a Mac II. At the time, any kind of computer video imaging was near rocket science. My brother was deep into Mac programming at the time and he wrote most of the code to read and display the images.

Journeyman

After college, I got a job in the upper atmospheric physics branch at Naval Research Laboratory. I finally had a real job and the lab was loads of fun.

We built satellite mounted instruments, which was something few people get to do. There were lot's of really cool instruments and test environments, the kind of stuff you see in movies. It wasn't always fun, of course. There's a lot of plodding and waiting puncuated by brief moments of shock and absolute fear.

Much of the flight hardware and software was already completed, most of my job was about testing and computer automation. I built hardware and wrote software to fully automate testing and validation of our instrument. I had an entire universe to myself.

Golden age

Government work was fun, but I wanted to try my hand in private industry. I left the lab and got a job at Watkins-Johnson, a defense contractor that specialized in high end communications equipment.

I was hired as a DSP engineer. I shared a window office overlooking the green, open fields surrounding NIST. My office mate was a brilliant, highly educated engineer. When we had little to do, he would lecture me on finer points of sampled systems and signal processing. It's rare to meet people with a deep understanding of a subject and the ability to explain it. I was truly fortunate, I thought.

I had access to excellent test and measurement equipment at WJ. I would stay late and build RF circuits, some as high as 20Ghz. I had the good fortune of meeting Barrie Gilbert, a brilliant engineer from Analog Devices. He came to WJ and presented some of the ideas he was working on. He was an amazing individual. There have been a few times when I knew I was in the company of world class intelligence, this was one of those times.

Back to the future

My job drifted more towards firmware and software over the years. It turns out that a lot more software is needed compared with hardware. It wasn't my first choice, but there's still challenge in it.

Now electronics is a hobby again. I own lot's of great test equipment, much better than anything I could afford when I was young. I've got several oscilloscopes, a spectrum analyzer, and a couple of synthesizers. I like to build small RF devices for remote control and monitoring. It reminds of the old days, but things have changed. Back then, I didn't know much, but I had lots of time. Now I know so much more, but I don't have the time.