Thursday, August 28, 2008

More culls from conferences

From cix (18 Apr 2003)

> hardly stressing the I/O on a mega128...

Yes, usually lots of I/O to go round on those. Mind you, that's no excuse for leaving it idle - I'm reminded of the time I had a 'phone call from some engineer who was practically incoherent with laughter having found my telephone number and a fairly raunchy message being output in morse on an unused output pin buried inside some embedded gear. . .

From cix (27 Mar 2005)

This reminds me (painfully) of a guy (Wookie) I used to work with back in the early 80's. He made serial ports that derived their timing from RC oscillators and was forever tweaking pots to get the damned things to work...

Back then we (Design Design) all lived and worked in a large victorian house in Manchester, and since Wookie was a radio ham, and I had various home-brew computers running noisily in the room next to him, we occasionally came into conflict - he was of the new-fangled opinion that computers shouldn't generate RFI, and I was of the old-fangled opinion that it was a minor miracle that the damned things ran at all, let alone that they should be expected to do so when enclosed in metal boxes.

The upshot of this was an uneasy compromise with Wook's aerials living in the attic and the attic floor and various walls of my room covered with aluminium foil.

On one memorable occasion Wookie had put some effort into designing some hardware/software to sit on the end of his comms receiver and decode morse transmissions, so that instead of learning morse you could just read the stuff in plaintext on a terminal. Why you should wish to do this at all is something that I never understood, but that's radio hams for you... Anyway, it occurred to me that some response was called for in honour of this, so while he was developing his morse decoder I quietly spent a few hours knocking up a piece of Z80 code to run on a small prototyping board and generate morse from text, and which would also drive a TTL port line up and down as fast as possible to generate enough electrical noise to transmit this signal... Generate a squarewave at several hundred KHz and there are bound to be harmonics all over the amateur bands, he's sure to stumble over one of them... Not expecting much success I left it repeatedly transmitting a loop of text.

The next day, with a few of us watching over his shoulder, he proudly tuned around the amateur bands hunting for morse signals and showing us his decoder locking onto them and decoding the morse. It was actually quite impressive, hand-sent morse can be a bugger to decode as the baud-rate varies so much. Eventually he happened across a very weak signal that faded in and out as we listened...

"Very weak, might be coming from the other side of the world" said Wook, "That'll be a good test!"

"Might be coming from the other side of the wall" thought crem...

Now, the message that *should* have been sent was [rummage in archived code]:


... which were phrases Wook had used the day before, plus a joke callsign, so I thought it wouldn't take him long to suss out they were from one of us. But I'd fucked up the lookup table in my code, so one of the letters was sent incorrectly. Add to this some errors from the decoder and gradually a confused message built up on screen.

"This is weird - sounds like someone I used to know, he used to say that about shit. Wish the signal was stronger, fading in and out like that means it must be coming from a long way away"

Frantic re-tuning from Wook. Frantic stifled giggling from crem.

"...Hmmmm. You know, I'm _sure_ I know this guy... he must have moved abroad... Hang on a second..."

A fair while passed, with Wook becoming more and more confused by this 'foreign' transmission and coming up with ever more bizarre explanations for its origin/purpose... Eventually, however, there was a dramatic pause as Wook started to realise he'd been had, which gave me enough of a head start to get away... Though it was touch and go - he was only a few feet behind after we'd descended three flights of stairs, nearly got me at the front door and would have caught me on the street if he'd been wearing shoes ;)

What's that got to do with pots, I hear you ask? My enduring memory of Wook is him standing over his prototype morse decoder and fiddling with various pots as he tried to decode this obscure foreign transmission.

( The original source code can be found near the bottom of this page: Source code )

From cix (7 June 2005)

And introducing crem's N+1'th law: "if you let someone else get involved with something simple, it will become complicated"...

From cix (22 Aug 2005)

We were warned - the people who introduced us to this application were fairly skeptical about putting anything technological in front of nurses.
Their opening remark was along the lines of:

"If you put a nurse in a locked room with two ball bearings she'd break one and lose the other"

From cix (8 Sep 2005)

This thread reminds me of the time I dragged myself out of bed and down to the kitchen at Des-Des towers (an otherwise unremarkable three-floor victorian dwelling in Manchester, where Design-Design used to lurk) and found a strange woman** sitting on a vibrating washing machine with a grin on her face. Being naive I asked her what was so enjoyable about the experience and was told more about internal sex aids than I needed to know... I decided against having eggs for breakfast.

Shortly after that one of the other guys arrived and, being even more callow than I was, offered to help redistribute the unbalanced load. This was not appreciated.

** I knew her very well - she was just strange.

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