In 1964, when I was in the eighth grade, I built a simple light-seeking robot. Looking back almost six decades it seems more remarkable now than it did then. While I was obsessed with learning electronics, I really didn’t know much.
It all started with a story in Popular Electronics. Every month there was a “Carl & Jerry” story about two young guys who built electronics gadgets and had adventures. John T. Frye started writing these stories in October of 1954, which I learned from an essay, An Appreciation by Jeff Duntemann. (Jeff has preserved all of these stories and offers them for sale on the same page. Thanks, Jeff.)
But I digress. That November in 1963 I read a story, The Lightning Bug. By this time Carl and Jerry were in college, studying electronics and dating. They built a robot, although they didn’t call it that, as a gag to scare some sorority pledges. The idea was this lighting bug would spring into action when it detected light from a flashlight in a dark barn, rolling toward the light making clicking noises and flashing a light on its tail. What happened was quite different, however. You’ll have to read the story to find out.
I liked the idea immediately. Simple and fun. So I committed to building something like it. I had a toy tank with dual motors which permitted it to steer by changing the speed of one track or the other. I knew I could buy some solar cells for sensing the light. All I needed was a couple of amplifiers to increase the signal from the solar cells to a level that could drive the motors.
But where could I get these amplifiers? I really didn’t know much about it then. What I did was pour over all my old issues of Popular Electronics to find circuits for simple amplifiers. There were lots of them to choose from so I picked the circuit with the fewest components. Doesn’t that seem like a reasonable idea? I did not even know Ohm’s Law yet, nor had I studied algebra yet or had the concept of amplifier gain.
I spent a month gathering the parts and fabricating what came to be known as Robbie’s Turtle. It used a six-volt carbon-zinc lantern battery for power. There were two heat-sinks for the two power transistors … I knew they were supposed to be on heat sinks but not really why … all under a plastic dome from a Ronson cigarette lighter display case.
No testing was done before the entire project was finished. Why would I test it? It would work, I was sure. Well, I turned out the light in my bedroom, flipped the switch to turn the turtle on and then pointed my lit flashlight at it.
It didn’t move. Not an inch. Completely dead.
I was devastated, deflated, demoralized and depressed. I could not understand it. I didn’t know what to do. Finally, I went downstairs and, nearly in tears, told my dad that it didn’t work. Maybe I even stomped my foot.
Looking back now I realize how much common sense my Dad had. He didn’t know anything really about electronics but he was smart for sure. His suggestion drilled right down to the core of the issue. How could I have missed something so simple and obvious?
He said, “Did you try a brighter light?” Wow. What genius. What insight. A. Brighter. Light.
I ran upstairs, took the lamp shade off of my bedside lamp and waved that bare light bulb (maybe sixty watts) close to the turtle and … nothing. But now I was on a roll. I went back downstairs into the closet and pulled out the big guns … my Dad’s four-bulb movie light-bar. My Dad saw me carry it by but didn’t say a thing.
Back in my room I plugged it in and turned it on … all four three-hundred-watt bulbs. The room lit up like noon on the summer solstice. Even behind it, the heat was palpable. But that mechanical turtle spun around toward me and came running.
By this time, my Mother and Father were standing in the doorway. I think they were proud. I know I was.
Updated: Apr 6, 2021 rs
