I’m considering continuing my high school teaching career at an alternative high school. I went to check it out last week, and the vibe couldn’t be more different than where I taught AP Computer Science last year.
That school had nearly 1,500 kids, this school has less than 100. It’s built around a maker ethos and in addition to classrooms, has multiple workshops filled with machines (drills and saws and lathes) alongside 3D printers, soldering irons and mixed media art stations.
Every afternoon the kids disappear into workshops and build.
While I was checking out the space, I spied a model rocket and launch pad leaning against the wall in a corner. When I was these kid’s age, I was riding high as president of the rocketry club. There was a little hobby shop next to my bus stop home, and I’d get so absorbed by all the rockets and gear, half the time I’d miss my bus.
I had shop class that year. My memory of Mr. Walsh is an old but round and jolly teacher. Seemingly unfit to wrangle 7th graders, he kept us in line with terrifying stories of lathes killing people with long hair.
It’s all fun and games until someone loses an eye.
But my favorite machine in the shop was the one you didn’t need safety goggles for — a TRS-80.
Mr. Walsh lived on the frontier. It was 1977 and the TRS-80 was brand new. He bought it with his own money.
It lived next to Mr. Walsh’s desk where he could keep an eye on it, and that’s where I hung out.
The TRS-80 booted into a BASIC interpreter, and it’s 4K of memory was just enough to load and run a small program. No disks — you saved programs on a cassette tape recorder that stored ones and zeros as analog audio tones.
Kind of like those old squealing modems.
We’d type in simple games like Hangman, line-by-line from a magazine. Every line of BASIC had a number: 10, 20, 30, etc. so if you messed up you could re-type that line by naming it, and you could also add new lines in between.
If you wanted your program to be around next time, you had to save it before the bell and that was a whole ritual.
Hit RECORD on the tape recorder and then CSAVE on the TRS-80. Stare at the tape slowly spinning for minutes until the prompt came back to life on the screen. To load a program from tape, you first rewound the tape and then hit PLAY on the tape recorder followed by quickly typing CLOAD on the TRS-80. Again the wait was agonizingly slow with no indication if it was working or not, and half the time it didn’t. The tapes were notoriously unreliable.
TRS stood for Tandy Radio Shack. The Apple II and Commodore PET also came out that year — the PC revolution was underway. But Radio Shack had an advantage over Apple and Commodore. They had over 5,000 stores worldwide, including one just down the street from me.
I could hang out in that store forever, browsing the back wall covered with little bags and boxes of electronic components. Switches, transformers, LEDs, battery packs, electric motors. All sizes and colors, each holding the promise of building something new.
I was a proud card carrying member of Radio Shack’s monthly free battery club and I got my dad one of their psychedelic AM/FM Radios for his birthday:
The summer before I met the TRS-80, my dad picked up this Radio Shack 150-in-ONE for me at a garage sale:
I’d hole up in my room, mad scientist like, hooking up circuits that buzzed and twitched and lit lamps. To connect components, you stuck the little bits of wire from the bin on the right into the spring connectors around each one.
If only I could combine my electronics infatuation with my rocketry one.
So I built a rocket launcher. This required every penny I had and many trips to Radio Shack. It was completely overengineered and I was very proud.
All you need to launch a rocket is 9 volts across a little igniter stuck into the bottom of your rocket’s engine nozzle. The igniter is coated with a bit of material that easily burns to ignite the rocket engine.
My launcher was a whole thing: once you inserted a special key to enable the circuit, it flipped on with a toggle switch, lighting up a red ARMED led on the front. Then we all screamed a verbal countdown in unison: 10.. 9.. 8 .. , and finally you launched the thing by pushing in the fat button in the middle, lighting up a second green LAUNCH led.
That closed the circuit, sending 9V down a pair of 20-foot wires out to the rocket.
Model rockets haven’t changed much, but computers have come a long way since the TRS-80.
I picked up one of these at the alternative high school:
The microbit is half the size of a credit card and it has a full ARM processor that would stomp the TRS-80’s z80 processor in a fight1 along with 32-times the memory at 128K and 512KB flash storage. No cassette tapes.
It’s $20.
I wrote a little program in Python, and loaded it on the microbit. Press the capacitive touch button in the middle and it counts down to rocket launch (banana for scale) with sound effects and smiley faces:
To make my new rocket launcher legit, I needed a few additional bits to send 9 Volts down a wire once the countdown finished. I bought a little breadboard with an electronic switch2 so the microbit can trigger a 9V source. I found an old bag of dome LEDs in the garage from my Radio Shack days and I can stick those in the breadboard too.
The gold band you see at the bottom of the microbit can plug into an edge connector. The five holes at the bottom are I/O pins that can control all kinds of external components or take in sensor data3.
You can even use the microbit’s accelerometer to record your movements and then use that data to train an AI/ML model that runs locally on the device. If I pick up a class at this school, we will be doing this for sure.
Radio Shack peaked in the 80s with 8,000 stores; alas they are no more.
While you can’t wander into a store anymore, there are plenty of online rabbit holes around for all us freaks and geeks.
My feed is now stuffed with advertisements for microbit robots.
I hope teaching these kids works out. I see myself in them, but while I grew up with a Radio Shack on every corner, they’re growing up in a very different world.
A world with a phone in every pocket and now a new, nefarious thing called AI.
Microbit: Nordic nRF52833, ARM Cortex-M4, 64 MHz, 32-bit
Vs
TRS-80: Zilog Z80, 1.77 MHz, 8-bit
MOSFET, aka: metal-oxide-semiconductor field-effect transistor.
0, 1, 2 are the first three controls, the 4th one is 3V output, the 5th one is ground.