Machine Learning: Foundations

When you want a person to do something, you train them. When you want a computer to do something, you program it. However, there are ways to make computers learn, at least in some situations. One technique that makes this possible is the perceptron learning algorithm. A perceptron is a computer simulation of a nerve, and there are various ways to change the perceptron’s behavior based on either example data or a method to determine how good (or bad) some outcome is.

What’s a Perceptron?

I’m no biologist, but apparently a neuron has a bunch of inputs and if the level of those inputs gets to a certain level, the neuron “fires” which means it stimulates the input of another neuron further down the line. Not all inputs are created equally: in the mathematical model of them, they have different weighting. Input A might be on a hair trigger, while it might take inputs B and C on together to wake up the neuron in question.
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The Lotus Sevens: The Real Most-Hackable Cars

In the late 1940s and early 1950s, Europe was still struggling to recover from the crippling after-effects of war. In Britain it is referred to as the “austerity period”, with food still rationed and in which “make do and mend” was very much the order of the day. The consumer boom of the late 1950s and 1960s was very far in the future, and if you were a hardware hacker your source materials were limited to whatever you could find from war surplus or whatever prewar junk might come your way. This was a time in which the majority of adults had recently returned from war service, during which they had acquired practical skills through the necessities of battle that they sought an outlet for in peacetime.

One field that benefited from this unexpected flowering of creativity was that of motor racing. Before the war it had been an exclusive pursuit, with bespoke cars at famous circuits like the banked track at Brooklands, in Surrey. In a reflection of the wider social changes that followed the war the motor racers of the post-war years came from humbler backgrounds, they raced homemade specials made from tired-out prewar motors on wartime airfield perimeter tracks like the one at Silverstone which still hosts Formula One racing today.

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Hackaday Links: October 30, 2016

Diablo. Mech Warrior. Every LucasArts game. There are reasons to build an old PC, and no, emulation cannot completely capture the experience of playing these old games. [Drygol] set out to create a retro PC and succeeded brilliantly. The built features an old desktop AT case (when is the last time you saw one of them?), a 233MHz Pentium with MMX technology, an ancient PCI video card, and an old ISA Ethernet card (with AUI connector). Incoming upgrades will be an ATI 3D Rage PRO, PCI SoundBlaster, and hopefully Windows 98SE.

Right now, we’re gearing up for the Hackaday Superconference next weekend. It’s going to be awesome, and we’re going to announce the winner of the Hackaday Prize. We have another contest going on right now – the Enlightened Raspberry Pi Contest. The name of the game here is documentation. Build something, document it on hackaday.io, and you get some cool prizes.

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Not Quite 101 Uses For An ATX Power Supply

The PC power supply has been a standard of the junk box for the last couple of decades, and will probably continue to be for the foreseeable future. A product that is often built to a very high standard and which will give years of faithful service, yet which has a life of only a few years as the PC of which it is a part becomes obsolete. Over the decades it has evolved from the original PC and AT into ATX, supplying an ever-expanding range of voltage rails at increasing power levels. There have been multiple different revisions of the ATX power supply standard over the years, but they all share the same basic form factor.

So a pile of ATX supplies will probably feature in the lives of quite a few readers. Most of them will probably be old and obsolete versions of little use with today’s motherboards, so there they sit. Not small enough to ignore, yet Too Good To Throw Away. We’re going to take a look at them, try to work out what useful parts they contain, and see a few projects using them. Maybe this will provide some inspiration if you’re one of those readers with a pile of them seeking a purpose.

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BASIC Interpreter Hidden In ESP32 Silicon

We’ve been keeping up with the ongoing software developed for the ESP32 WiFi chip, and that means a lot of flashing, hooking up random wires, and rebooting. Along the way, we stumbled on an Easter egg: the ESP32 processor has a built-in BASIC interpreter to fall back on.

That’s a cool little hack to find, but we couldn’t find some crucial functions that would have made it a lot more useful. Still, it’s great fun to play around in real-time with the chip. And you’ll absolutely get an LED blinking faster in ESP32 BASIC than you will on an Arduino!

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Parts You Should Know: A Universe Of Useful Injection Molded Standoffs

Your clever branding won't work on me! *types caption in on iPhone*
Your clever branding won’t work on me!
*types caption in on iPhone, sips Starbucks*

I remember the first time I built a computer. My sister and I had our last fight about who would get to use the family computer, it was time I had one of my own. I knew a little bit, and I knew I wasn’t going to be one of those plebs that overpaid for a Gateway in its cow box. So I outsourced. One of the computer literate parents in my Scout Troop very kindly agreed to put together a list of components for me. I spent my Christmas money, birthday money, and a small mountain of money I had saved up. I remember getting the parts in the mail. I was so excited that a week earlier I had even bought one of those super lame computer tool kits to put it together.

I still remember how enormously frustrating the stand-offs for the mother board were to install. I think computers were still figuring out that they didn’t need ALL of the features of a mainframe. Anyway there was a 3mm screw on each side of a cm tall brass standoff. It also wanted me to put these little isolating paper washers on the assembly for some reason. Even with my then presidentially sized hands it took a long time. My Mom later told me that it was around this time she was certain the whole endeavour was going to end in tears.

Six hours of careful work later I had the computer together and running when I realized I had forgotten to buy an OS for it. She was nearly right.

Regardless. My early experience with computer assembly left me with a love for standardized screws, a hate for excessive fasteners, and a deep loathing for improperly routed wires. I was a weird kid. Anyway, when it came time for me to start designing my own enclosures for circuit boards I had all the unique psychological damage and underpinnings I would need to waste a lot of time googling on the internet for an alternate, screwless, method of standing a board off from a surface.

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Sailing Ships, Slide Rules, And The Quality Of Engineering

We recently ran a post about engineers being worse, better, or the same than they “used to be” and it got me thinking. Of course “used to be” is in the eyes of the beholders. To me, that’s the 1950s and 1960s. To some of you, my generation is the “used to be” generation. To some of you, I’m past even that.

I’ve often said, there are two things that are simple: something really simple, and something really complex. For example, when a caveman grabbed a log floating down the river and hitched a ride a few miles downstream that was pretty simple. Today, you can go on a well-equipped boat, stab your finger at a map, click go, and the boat will do almost all the work. However, get onboard a sailing vessel from 1850 and you better know what you are doing. What’s more is, some sailors were better than others.

What’s Better or Best?

Were yesterday’s engineers better than today? That’s like asking who is the “best” driver. It depends a lot on what “best” means. Safer? Faster? Most efficient? I would suggest that yesterday’s engineers were better at doing yesterday’s jobs. I own several slide rules and I can use them, but I bet my mentor who finished college in the 1940s was faster. I don’t need to be faster. On the other hand, he might have some trouble doing a good Internet search.

But here’s the problem. Doing basic math is like the caveman on the log (and yes, that begs for a slide rule joke). Asking Wolfram Alpha to solve your set of simultaneous equations is like the modern computer-controlled ship with GPS. You can bet that the sailing master of a barque in 1850 knew a lot more about sailing and winds and ship construction than the average guy on a modern ship. He had to. That gave him extra reasoning tools when faced with a problem.

Slide Rules Do (Most) of the Math

By the same token, using a slide rule is very helpful but–paradoxically–you have to know a little math to be able to use it. In particular, you had to have a rough idea of the magnitude of the answer to get the right answer. If you couldn’t get that concept or do the simple estimate in your head, the slide rule was useless and you probably dropped out of engineering school. Today, you may or may not have that kind of math smarts, and it doesn’t matter.

I’ve known graybeards that keep up with the modern technology. I’ve also known plenty who are stuck in the past, talking about how horrible transistors, or ICs, or software is and how it has ruined everything. Of course, they haven’t.

Lesson Learned

As Gerrit pointed out, we tend to remember the brilliant engineers and projects and forget the bad ones (unless they are really bad). Even in “the golden age” there were good engineers and bad.

So how can you maximize your chances of being one of the good ones when this turns into some kid’s golden age? Two things, I think. Never stop learning the new technology. The hot-shot engineer with the slide rule wouldn’t function as well in today’s world unless he was willing to learn about the new things. But also, learn the fundamentals. You don’t have to know how an engine works to drive a car. But all the race car drivers do know. Having tools to do circuit analysis or solve thorny math equations is a great time saver. But you ought to know how to do it without those tools. The insights you’ll gain will give you more tools at your disposal when faced with a problem.

Engineering is a series of abstractions. Always try to drive down the abstraction layers. Know how to program? How does a CPU work at the logic gate level? Know how that works? Then how do the transistors form those gates? When you understand that, dig into why the transistors work at all. Sure, you probably aren’t going to build a transistor from raw materials. But you’ll gain new insights and those insights will help you solve future problems. Besides, if there’s ever a zombie apocalypse, it might be good to know how to use a slide rule or build a transistor.