As a teenager, with a couple of friends, we decided to borrow a couple of sticks of dynamite to celebrate. Those things were ancient, quite moldy and a little sweaty. We wrapped them in cloth and took them to the river bank.
Morning test was unsuccessful. The detonator blew, but not the dynamite.
We shallow buried the rest under the sand and let the summer sun bang on it all afternoon.
We returned in the evening to give it another try…and boy o boy, who knew it could rain pebbles and sand.
That was one of those times I could have died before turning 20.
Before people were used to taking their music with them with their phones and IEMs, and the odd audiophile external DAC...
...yours truly decided to take my music with me. As an engineer I wanted to take my Zappa on the 737.
The resulting contraption was composed of two electrical boxes, one battery, a bunch of cables, a couple of external LEDs in a home made box all held together with some robust rubber bands. And for headphones I carried my Grados.
The first time I tried to take that through airport security in early '02 I was given the Royal Treatment.
What saved me was that I was travelling in business, had my work badges and security clearance, etc... needless to say, I took it all apart on the return trip.
After that I got an iPod, it was a lot safer to take even if its DAC sucked.
Oh... explosives, yeah... the first power supply I built at home... was pretty big, four BIG caps, about six inches tall, two inches across... I forget but I think it was 48v.... but I was in a hurry and didn't have a power switch... I mean, I was almost 20 years old, invincible. What could go wrong, right?
It took a long time to clean up the mess. Thankfully the switch was low by the wall and I had to lean over to plug it... and unplug it.
Hmm..
...yours truly decided to take my music with me. As an engineer I wanted to take my Zappa on the 737.
The resulting contraption was composed of two electrical boxes, one battery, a bunch of cables, a couple of external LEDs in a home made box all held together with some robust rubber bands. And for headphones I carried my Grados.
The first time I tried to take that through airport security in early '02 I was given the Royal Treatment.
What saved me was that I was travelling in business, had my work badges and security clearance, etc... needless to say, I took it all apart on the return trip.
After that I got an iPod, it was a lot safer to take even if its DAC sucked.
Oh... explosives, yeah... the first power supply I built at home... was pretty big, four BIG caps, about six inches tall, two inches across... I forget but I think it was 48v.... but I was in a hurry and didn't have a power switch... I mean, I was almost 20 years old, invincible. What could go wrong, right?
It took a long time to clean up the mess. Thankfully the switch was low by the wall and I had to lean over to plug it... and unplug it.
Hmm..
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Get grab bags of electrolytic capacitors from Poly Paks, or wherever (even Radio Shack). Inevitably you get stuck with some useless ones. What in the world are you supposed to do with a 6.3 volt cap? Every circuit I’m working on needs more than that. I know exactly how many volts to give it (and it’s not VDC, too).
Then there was the big capacitors I took to school. Charge them up and spark them on things. Of course you need an effective charger too. There’s only so much one can do with a 9 volt battery. And E equals 1/2 C V*squared*. Little device that would very effectively charge up a 2700 uF 250 volt soup can electrolytic (in a minute or two). Two 9V batteries and a 4049 driving a FET H-bridge, into a 12:120 transformer, then a full wave bridge. The loading of the cap drags it down, so it does take a bit to charge but it does. BANG on any piece of metal. But wait there’s more! Switch the rectifier OFF and put AC at the terminals and it puts out a pretty good whallop to whatever victim I can find. Far better than the inductive-kickback shocker (disguised in a tape recorder) I brought last year which ate C batteries for breakfast. This was in middle school.
The capacitor idea followed me to college where I built the “Spark-o-Matic” out of as many 75V caps as I could haul back from Skycraft. Two pieces of welding cable and 4 foot sections of EMT, and you have “Electric Fencing”. En Garde. POW! Or, In the end there can be only ONE. Taking a single 2700 uF 250V cap to the cafeteria on Steak Night. “You will give me three steaks, right?”. Sparks the cap on the stainless (not anymore) counter. Gets three steaks.
Guess I shouldn’t really be surprised if someone asked me if I was building a bomb etching a harmless PCB in the dorm room.
Then there was the big capacitors I took to school. Charge them up and spark them on things. Of course you need an effective charger too. There’s only so much one can do with a 9 volt battery. And E equals 1/2 C V*squared*. Little device that would very effectively charge up a 2700 uF 250 volt soup can electrolytic (in a minute or two). Two 9V batteries and a 4049 driving a FET H-bridge, into a 12:120 transformer, then a full wave bridge. The loading of the cap drags it down, so it does take a bit to charge but it does. BANG on any piece of metal. But wait there’s more! Switch the rectifier OFF and put AC at the terminals and it puts out a pretty good whallop to whatever victim I can find. Far better than the inductive-kickback shocker (disguised in a tape recorder) I brought last year which ate C batteries for breakfast. This was in middle school.
The capacitor idea followed me to college where I built the “Spark-o-Matic” out of as many 75V caps as I could haul back from Skycraft. Two pieces of welding cable and 4 foot sections of EMT, and you have “Electric Fencing”. En Garde. POW! Or, In the end there can be only ONE. Taking a single 2700 uF 250V cap to the cafeteria on Steak Night. “You will give me three steaks, right?”. Sparks the cap on the stainless (not anymore) counter. Gets three steaks.
Guess I shouldn’t really be surprised if someone asked me if I was building a bomb etching a harmless PCB in the dorm room.
I built this booster amp in high school electronics class, 1969 or 1970. Two big caps, and two bigger caps. The circuit that I used was lifted from a RCA transistor manual and was quite popular in the 60's for HiFi use with germanium transistors in the 20 to 40 WPC range. Of course, I supersized it. The power supply was made from components taken from surplus electronics, the driver transformer was DIYed on the core of a Radio Shack filament transformer and the output parts were 6 X house numbered "2N3055's." B+ was about 100 to 110 volts depending on line voltage and primary tap on the 75 volt 4.5 amp transformer. Power output was believed to be in the 300 to 400 watt range into a 4 ohm load. We did not have a test load for this power level so we used a large (several laps around a big classroom with multiple workbenches) loop of wire that measured 4 ohms. That likely changed as the wire heated. THD? " A lot." The old vacuum tube THD analyzer wandered around 5 to 10% as clipping was approached. I used this thing with a pair of DIY 4 X 12 inch guitar speaker cabinets to keep my status the loudest guitar player in high school. Remember I built this thing in high school at age 16 or 17. Note that the power cord is soldered directly to the power transformer, no fuse or switch in sight.
Somewhere in the 70's it wound up in a box. Somewhere in the 80's that box wound up in a shed behind my house. In 2005 Hurricane Wilma rearanged the roof of the shed. Sometime in 2007 I dumped out the box that contained this amp. Now what? I get a long extension cord, set the thing in the street in front of my house, and plug it in.....from 50 feet away. When the plug hit the wall outlet it was obvious that some serious current was being drawn. Smoke, steam and electrolytic stink was flowing from underneath and the blower was forcing a column of toxic mess upwards through the heat sinks. Unfortunately, the fun ended prematurely before one of the big caps went bang. It seem that the rectifier diodes shorted which caused the line cord to melt where it was plugged into the extension cord. Funtime over. I kept the heat sinks and tossed the rest in the trash.
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I got a big box of these caps at a hamfest around 1980 for a project I was making copies of one or two a week. After several years those devices began to fail due to open caps, so I quit using them in projects. I noted that the lead spacing fit properly into the end of an extension cord, so they became remotely activated firecrackers. These caps from 1974 do not have a vent, so they make a pretty big bang. I had forgotten about them until I started going through some old boxes. There are only 7 left from a box that had a few hundred.
I worked in an off campus "think tank" for a few years in the early 90's. We had a project that built maybe 15 or so prototypes, then died leaving behind a box full of parts. My Spark-o-Matic was made from all the power supply caps wired in parallel with #14 solid copper wire. I think they were 35 volt caps, so it didn't make too big of a bang, but I left my mark all over that warehouse building.
I was wandering through Skycraft one day in the mid 70's before they organized the place. There was "stuff" everywhere, including a room full of caps. I spot this giant electrolytic cap that was at least a foot tall and rated for maybe 200 volts. I got it for $5. I don't remember the exact specs, but it's voltage rating was enough for rectified wall outlet. I charged it with a light bulb and a diode in series and used it to make small parts disappear. AKA the parts tester......all parts fail!
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Made buss bars out of those adjustable shelf hanger rails for mine. Throw a shaken up can of Pepsi or beer across them and makes an even bigger mess than an exploded 470 uF 6.3 volt cap. There were pits on every light fixture and outlet box in Alpha 336. And a lot out in the hall - tie to the building ground and it sparks on everything. Some in 236 where the etching solution stain was too but that was with fewer capacitors before the big skycraft haul. Just the four I got from the surplus house I got the 80VCT 500 VA trafos for the KM441’s from. We kept the big one right at 75 volts because it wont kill your opponent if you score a touch but they do feel it, and ran cheap caps right up to the limit. 48 volt transformer, and one of my 5x100W disco light boxes as the dim bulb limiter. With enough uF it still makes a pretty good shower of sparks. It was some 300-400 joules.
For real big bangs you need a "death cap." Not the kind you find in old guitar amps but the kind that can cause death or in the proper hands, prevent it.
While I was working in the think tank, I got tasked to reduce field failures in a golf course lighting and irrigation controller called OSMAC before the product was sold to the Toro lawn mower company. The little off grey box typically has underground wiring connected to solenoid valves along a large area of a golf course. Note the "feature" on the left. Guess who, and how it was designed.
https://www.toro.com/en/product/E-Series-Osmac#specifications
I needed to "create a lightning strike" in the lab. After some discussions with some like minded (crazy) friends an ex-Motorolan who owned a medical equipment repair service recommended an old defibrillator and gave me one that was too old to be certified in the USA. The knob goes up to 400 Joules. The 16 uF 7.5 KV cap out of it can be seen in my 833A test amp. The last OSMAC I saw was in the mid 90's and after an output board redesign it could eat a single blast from the de-fib with its output inductor bypassed. Note that a pager subjected to the same test had its 4 layer PC board split into two blackened 2 layer boards with most of the components vaporized.
While I was working in the think tank, I got tasked to reduce field failures in a golf course lighting and irrigation controller called OSMAC before the product was sold to the Toro lawn mower company. The little off grey box typically has underground wiring connected to solenoid valves along a large area of a golf course. Note the "feature" on the left. Guess who, and how it was designed.
https://www.toro.com/en/product/E-Series-Osmac#specifications
I needed to "create a lightning strike" in the lab. After some discussions with some like minded (crazy) friends an ex-Motorolan who owned a medical equipment repair service recommended an old defibrillator and gave me one that was too old to be certified in the USA. The knob goes up to 400 Joules. The 16 uF 7.5 KV cap out of it can be seen in my 833A test amp. The last OSMAC I saw was in the mid 90's and after an output board redesign it could eat a single blast from the de-fib with its output inductor bypassed. Note that a pager subjected to the same test had its 4 layer PC board split into two blackened 2 layer boards with most of the components vaporized.
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The problem is that a 7.5 kV source can put 400 joules into you. A cap bank charged up to the same, with only enough voltage to let a little current flow into skin resistance can’t.
But into a low resistance object, like a Pepsi can or your boss’ new Klein screwdriver….. it gets the full 400. Or at least the lion’s share of it.
But into a low resistance object, like a Pepsi can or your boss’ new Klein screwdriver….. it gets the full 400. Or at least the lion’s share of it.
That cap was from a de-fib unit, intended for zapping humans back to life when their heart stopped for whatever reason. I used the complete de-fib unit minus its output inductor to create artificial lightning for testing OSMAC control boards. After that project ended, I kept the cap and tossed the rest of the de-fib. The cap lived in a box until I built that test amp. I don't think it made the trip when I left Florida, if so, I have no idea where it is. The scary thing it the 1500 volt 1/2 amp power supply that is connected to that cap via the Yellow Radio Shack clip lead. In all but a few carefully staged pictures, a 1/4 inch thick sheet of Lexan was between me and that amp. I had three of those power supplies. I tried to sell them, trade them, or give them away. Nobody wanted them so they went to the metal scrapper complete with their 40 pound transformers.
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As a kid I lived in the Western Australian 'wheat belt' in a tiny farming town. It was common for farmers to have gelignite to blow stumps and rocks out of fields and the kids used to get their hands on it and have all sorts of fun. We used to have to steal fuse from the local general store whose security was so lax, we could reach in through louvred windows and cut off any length of this orange coloured cord fuse. I think back at all the things that could have gone wrong with the gelignite as we blew up a few old contraptions farms always had laying around.
Less dangerous, but we used to take the lead off .22 magnum rounds and crimp fuse in them, light them up and throw them on the tin roof of the local miserable old sod's house to annoy him - you know, every small town has one of these killjoys. Mind you I think back and we were quite bad to this guy.
Back then we also had access to about 100 boxes of WWII era .303 shells (year stamped, I still have one 5 shot magazine). A few families had a Lee Enfield. In fact, one of my indigenous Australian mates had a Lee Enfield .303 with the stock roughly cut down into a pistol. Crazy.
We experimented with all kinds of contraptions with the sticks of spaghetti like cordite out of those. My favourite was when we took a soda fountain capsule, opened out the nozzle, packed it with cordite and attached it to a model boat. Then down to the town water supply dam to test our 'rocket boat'. We're all leaning over this thing and set light to the 'motor'. BANG!..........wait ten seconds......ears ringing......then we hear the sound of metal tinkling down the other side of the dam, with the boat remains floating down bit by bit over the water.
Or setting fire to the local rubbish tip, then placing empty 20 litre drums on the fire and hiding. And who should turn up to dump some rubbish? Mr Miserable, just in time for a drum to pop. BANG! We could hear his squeal from 50 meters away and he was outta there, probably the first time he'd broken the speed limit.
We escaped injury though, somehow.
Stuey
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Those instruments..... HP, Tektronix, Sony, NEC.. is that a Compaq?
Reminds me of the time we hooked up my walkman to test the new shaker table. Playing Sympathy for the Devil. Found new standing waves in the building. The guys in the 2nd floor thought it was The Big One and came rushing the stairs outside.
We never told anybody.
Actually, we couldn't. We locked the door to the lab and we were ROTFLOL... it was so funny.
The PC is a DIY machine as I never bought a completely built PC. I don't remember what I had in it since I played musical parts often. The blue plastic case could have been from a Compaq or whatever case I found at a hamfest, computer show, or flea market. It was likely a cheap but flashy "build your own PC" case like those found in the giant Computer Shopper magazine that was popular in the 80's and 90's. The monitor was an ex Motorola HP unit that wound up at a computer show after the lease was up. It still had the Morotola control number tag on it when I bought it at the show. Mot leased most of their PC's as did a lot of companies.
Compaq made a "luggable" PC that was about the size of a sewing machine. It had a 9 inch or so B&W CRT screen a 80286 motherboard and the keyboard was used as the cover when closed up for movement. It took the clone vendors about 3 weeks to clone that case and put it on the market. I had built one with an 80486 board in it when I was going to college in the early 90's. I dragged that thing to class since it beat all the crap that the school had in their computer lab.
We had an old shaker table that had a bunch of big tubes in it (6550's maybe) and a pair of transformers the size of a small file cabinet. It was replaced by a new programmable solid state unit in the late 80's. I remember using a profile called "Military Jeep" turned up to 10 mm excursion to rip some radio equipment apart. The old vacuum tube unit vanished before I could find out where it went.
Those pictures are about 20 years old. From the late 70's through about 2000 Motorola used to sell "scrap" equipment at auction. Employees got early access. I always bought a van full of stuff that I fixed up, then quietly sold piece by piece to pay for the lot. I kept the good stuff for myself. Someone with a lot of money and no brains bought up all of the old Cushman communications analyzers at one of those auctions, fixed some of them up, and took out an ad in Communications Magazine trying to sell them. Sonce Motorola also sold Motorola branded comm analyzers, these people were in direct violation of their employment agreement, ending their employment and all future auctions.
That’s the thing.
I’m not proud of all the crazy antics; I just marvel at how lax my supervision was and at the fact I survived through it all.
It seems you were even more creative and lucky!
I think we all have them, and, ironically, they enrich our lives. But kids in the west now?
It wasn't that I did anything quite as death defying as what's been related here, but being out, climbing stuff, falling off it, I had my fair share of "you're as close as you'll ever be".
Of course, at the time, I never appreciated those narrow margins. I do now, and treasure my luck.
Yeah, one of those times was when we used to go into the town's main wheat silo, a massive concrete structure I guess 100 metres long by 30 and 30 high and climb onto the steel roof and through the lattice superstructure, then jump into the wheat. Us kids had spoken of the stories of kids being smothered by wheat, but ah well...we'd tested it and it seemed stable enough...
Dad used to blast us but we'd end up back there next harvest. Thinking back, I'm surprised it wasn't locked. You could slide a hatch on each massive door and climb in.
If interested, you can see the silo it in the background in this picture https://purl.slwa.wa.gov.au/slwa_b4316617_2 It's the one with the two bits of machinery sticking out the top.
Last one I promise. I love telling the story of how I rode a Harley Davidson to school every day, never wearing a helmet, from the age of about 10. I just used to park it in the bush. After the incredulity subsides a bit, I admit it was a small trail bike Harley made in the 70's in collaboration with Italian firm Aermacchi...
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And we used to go to the trails out in the game preserve with those things, in shorts and no helmet. Can’t think of a better place to get hurt and not be able to get help. I never owned one, so more often I was out there on the kind you pedal instead of the ones that run on 2-cycle mix. But it did happen often enough and I wasn’t that skilled a rider due to lack of practice. I never did go on motorbikes alone (because mine would be borrowed, and somebody else would drive the truck out there. Didn’t have one of those either). Now on the bikes you pedal, I could stay upright through damn near anything. This was before mountain bikes. Think 10-speed, 27x1.25 tires, sand and gravel. And I’d go out from sun up till darn near midknight. All sorts of ways to get in “trouble”. Technical trails (only meant for 4x4’s), caves, and old phosphate pits. And about 100 square miles to get lost in.
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5 years ago I was making regular orders from Mouser and Digikey. I was ordering multiples of chips, transistors, resistors, the usual suspects. One of my orders was delayed a few days (did not raise an eyebrow) but when it arrived it had been opened and rifled through. It was flimsily taped shut and delivered.
I'm pretty sure that authorities were suspicious of my activities in the shop. Any kind of custom circuit is automatically part of a bomb in their small minds. (Same way a cop thinks everyone he has contact with is in the process of committing a crime; the old Chicago "Serve and Protect" ethos).
Tone control board? Bomb. DSP board? Bomb. Audio amplifier module? Bomb. Everything is a bomb bomb bomb bomb. The only reason anyone would build custom electronic circuits is because they're building bombs. And the irony is that I could easily build a bomb controller circuit from the jars of prototype parts I have on my workbench (I use them over and over in prototypes until they fail).
I'm pretty sure that authorities were suspicious of my activities in the shop. Any kind of custom circuit is automatically part of a bomb in their small minds. (Same way a cop thinks everyone he has contact with is in the process of committing a crime; the old Chicago "Serve and Protect" ethos).
Tone control board? Bomb. DSP board? Bomb. Audio amplifier module? Bomb. Everything is a bomb bomb bomb bomb. The only reason anyone would build custom electronic circuits is because they're building bombs. And the irony is that I could easily build a bomb controller circuit from the jars of prototype parts I have on my workbench (I use them over and over in prototypes until they fail).
My dopey brother (RIP) hung around with a bunch of Soldiers of Fortune wannabes. They were a motley crew of car thieves and card-carrying N@zis, no lie. They were building pipe bombs in my parent's basement. I was away at college so I couldn't do anything about it. Anyway, one of the goons whose street handle was "Goose" decided to blow up a guy's house over a bad drug deal. The guy lived with his parents. They drove by the house while Goose hung out of the back window of the car, holding the bomb. It exploded while he was holding it, costing him his right arm above the elbow.
So now he's known as "Doctor Hook." Last I heard he was rotting in prison.
When my father sold the house, I spent a lot of time there going through 40 years of stuff and getting everything ready. Under the workbench I found a couple boxes with stuff to make pipe bombs. I went right across the driveway to the house next door, where a high ranking Chicago Police detective lived. I gave him the boxes through the back door. He was laughing as he looked inside the boxes. He knew my brother and his band of thugs quite well.