I like eating pi

Okay, so I’m not a big pie fan. I’m not even really a big pi fan… damn irrational numbers. Right? 3.14etc… that’s irrational, right? Anyway, I’m not a big fan of that either.

However, I was poking around at a few things earlier on the internet, and ran across this:

Rasberry PI supercomputer

Well, I found it quite intriguing. I remember reading about the raspberry pi computer months ago. It is a self contained computer, no bigger than an iphone. Sure, it doesn’t have a lot of power, but for something that has the power of a pentium 2, 300mhz, complete with the video quality of the original xbox, all in a package costing $35, that’s pretty incredible.

raspberry_pi_iphone

 

Of course, it requires an SD card to hold the programming, but will connect to an external USB hard drive or even an ethernet hub. I thought that was pretty incredible. I did a fair amount of electronics crap when I was younger. Of course, it was mostly analog stuff, a few transistors here and there, some timer ICs, coils, capacitors, etc., and nothing really involving programming. Sure, I could do a little BASIC programming on the computer, but my electronics didn’t require it, they were mainly a “switch it on and let it run” sort of thing.

My biggest projects usually involved radio. I wanted to be a radio pirate at one time. I loved listening to shortwave, and always hoped to hear pirates, but it was years later when I happened across one. I wanted to broadcast my own music and thoughts over the air. Of course, thanks to the internet and social media, anyone can really be a “broadcaster” now. Anyone can respond. And it’s all legal, which means it’s not nearly as fun.

Of course, any serious radio broadcaster needs a radio transmitter. At the time I was around 18, I was NOT interested in getting a HAM license or spending hundreds on antennas and transmitters and such. I did eventually put together the funds to buy a decent CB transmitter.

rci2950dx

 

The RCI 2950 was a combination CB unit/HAM 10 meter transmitter. 10 meters is down around 28mhz (You probably listen to radio stations which are all between 88-108mhz)  The guy I bought it from tweaked it so it would do 8 watts instead of the legal limit of 5. Of course, everyone in my area was running at least a few hundred watts through linear amplifiers. My goal was to eventually build a 40 meter transmitter so I could talk down around 7.5mhz. Funny thing about radio: the lower the frequency, the easier it bounces around the planet. So sitting in your car, you might be able to tune in a decent commercial channel at 100mhz somewhere around seventy miles away, running close to 100,000watts of power. Meanwhile, you could also tune in a decent amateur signal at 7.5mhz, running 100watts of power, from 3000 miles away.

So, before I built or bought a transmitter, I figured I better learn to build a decent amplifier, which at the time was cheaper and easier to do with tubes than transistors. Below is an old tube-based audio amplifier, which essentially works the same way. Using high voltage and some vacuum tubes, a weak signal is made stronger.

linear6c

 

Sourcing parts before the internet was always tedious. Even then, Radio Shack (You’ve got questions? We’ve got blank stares!) didn’t have everything, and I had to pour over catalogs from companies that are now vanished, looking up things like RF chokes and coils and variable capacitors. Military surplus was always fun. I ran across an old AM amplifier in the attic the other day. It has a serious roller inductor inside, probably worth more for the copper than I paid for the unit.

Anyhow, amplifiers were cool, because they involved tubes and high voltage. Tubes have a little heater inside, so they warm up and glow nicely. And high voltage, well Hell, what teenage boy doesn’t want to play with high voltage? A friend of mine built a Tesla Coil once. Coolest toy ever. I still have plans around here for it, somewhere.

Tube amplifier experiments were cruelly subjected on the local radio group, though. I would test something, change it a bit, tune it up, and test it again, all while annoying some of the local hicks with my questions. Louder or Softer? Better or worse? It was the radio equivalent of an eye test by an eye doctor that really doesn’t know what he is doing.

Of course, sometimes it was dangerous. The scariest moment of my life involved one of those damn amplifiers. It wasn’t running, mainly because I couldn’t find a few of the stranger parts, and had to keep trying different things. It’s plate voltage came from a big ass transformer weighing in at over 10 pounds. It took the wall current (120v for you non-US people), and boosted it to 1200 volts, and put out an amp of current. It was a scary beast. The thing was, It was plugged into the wall next to something else, with a very similar plug. I of course, unplugged the wrong one, and in a moment of foolishness, grabbed the wrong wire coming from the transformer.

Now, I’ve been shocked with a TASER gun, three or four times (in the course of events at work, not because I’m a dirtbag that needs to get zapped). That hurts. Seriously, it’s uncomfortable.

Grabbing a 1200v, 1 amp source should kill you, and is unbelievably painful.

It made me stand up out of the chair, and thankfully my fingers came loose from the terminal at that point, whereupon I fell over backwards, and lay prostrate upon the floor. Several seconds went by as I stared at the ceiling, and finally breathed again.  When I could move once more and my scrambled brain realized what I did, I unplugged the thing and put it in the corner. It never did work like it was supposed to, those RF Chokes and coils were unobtainable, and I couldn’t tune the thing right. I gave up my radio toys when I went away to college, and never really got into it afterwards. After all, I bought my first computer (an intel 386 with a whopping 40 Megabyte hard drive!). I can’t even find a photo of it on Google – it was a slim case by WYSE, a model called the Decision (get it, Wise Decision?). It looked like something you would see under a cash register terminal, but it worked, and I learned to use the internet (My first modem was a 7400 baud model – DialUp topped out at 56,000 baud, if you didn’t know).

So – Back to Raspberry Pi.

The idea of a $35 computer toy to play with sounds very intriguing. I don’t know about learning a new programming language. I struggle enough with the little bit of HTML I know, and I remember a few phrases of BASIC. I can recognize C++ when I see it, but I could never understand it (I had a book… I couldn’t get past chapter 2). I sure as hell don’t like the looks of learning Python or Java. A Python is a snake, and Java is coffee. What happened to the really geeky-sounding languages? Fortran and Cobol and Linux… those were names.

But at least I’m not playing with voltages that come close to what’s in the electric chair… which I have sat in. Some of my co-workers were very disturbed at the fact that I have sat in our state’s electric chair. 263 men and women (and one 14 year old) have sat down in that chair and never got up. I felt a little humbled and honored to be able to sit in it and walk out with my soul intact.

But that’s another post.

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Author: theosus1

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2 thoughts on “I like eating pi”

  1. I am so glad you know of what you speaketh—–and that the zappy thing in the wall didn’t send you to the great beyond!!!!!!!!!!!!!

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