SFPC Week 3: Soldering is Satisfying

Hello, World. A one bit computer is born.

By the hands and mind of a complete beginner.

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In simplest terms, a computer is 3 components:

1. Adder
2. Clock (oscillator)
3. Memory

But before we build a computer, first, a simple circuit. Hardware is uh… hard, so we took a week to learn about circuitry and logic, step by step.

Voltage regulator hooked up to a battery, LED, and resistor.

Thinking with my hands helped me integrate what I was being taught, especially once we put a switch in to build a latch (to turn the capacitor on or off). Basically, there are two paths the electricity can go here: one path is longer, but always open; the other path is shorter, but only open when we say so (via the switch). Just like people, electricity wants the path of least resistance. I had to build this circuit first before I actually understood the concept.

Circuit v2 with a switch and capacitor

Once we had the basics down, we started playing with a breadboard, so as to not deal with so much copper tape (looks pretty, kind of annoying to handle). Breadboards are a prototyping tool for electronics, and we started to actually program some logic.

Basically: logic gates are the DNA of computing and the NOT AND (NAND) gate is the MVP. You’ve got a bunch of different types of logic gates that take binary inputs and give you an output. You can mix and match NAND gates (which are programmed into chips) to get the output you want.

This is decidedly nerdy, but figuring out the combinations of NAND logic gates to get other logic gates was satisfying.

Logic gates and their binary inputs and output

Circuit schematics, creating logic gates out of NAND gates only.

Now, on to the actual one bit computer. We were working off of a prefabricated printed circuit board (PCB), so most of the learning in this class was about soldering for me. (Including that soldering is spelled “soldering” and not “soddering”, but hey, ya learn something new everyday). You can see my progress from left to right — from crunched-up-aluminum-foil-looking joint to smooth-shiny-hill joints.

Soldered joints on the back of the one bit computer

Once finished, we had a computer that could store one bit of information in its memory (i.e. whether the light on the lower right hand corner was on or not).

Once I hit the switch, I activate the latch, which tells the computer to store information that says the light is on.

The clock / oscillator is telling the light how fast to blink. The other two LEDs on the top right-hand side are part of the adder, controlled by the two switches up top.

If you’re curious about handmade computers and want to learn more, check out Taeyoon’s process here.

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This is my weekly reflection about my experience at The School of Poetic Computation. Follow these links to read about my week zero; week one, week two.