Old EPROM questions again, EPROM Programmer

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Thu Jul 29 19:04:22 2004

> >> Well I know I'm a lot more selective about my TV and movies than the
> >> majority of people but are you trying to tell me that there's NOTHING worth
> >> watching on TV or movies? What do you have against women, beer and sports?
> >
> >I watch _very_ little TV, and wouldn't bother at all if I had to pay for
> >the license (as opposed to watching my parents' set). UK TV is pretty
> >darn awful....
>
> Same here but we now get enough channels that you can USUALLY find
> something worth watching. The Discovery, Wings and History channels are

Very different in the UK. Most of the stuff on the standard 5 channels is
terrible, and from what I've seen, the digital/satellite/cable channels
aren't much better. Serously, I'd much rather be using a soldering iron...

> actually coming out with some pretty good stuff.

> >I assume you think the chap who wrote 'The Voice of the Crystal' and
> >'Instruments of Amplification' was wasting his time.
>
> I've never heard of either one.

They're actually quite interesting books. 'The Voice of the Crystal' is
about making crystal radios using _no_ commercial electronic components
at all. He makes his own coils (trivial), detector (using a similar
design to the ones made 100 years ago), variable capacitor (suprisinging
hard to make, acually), headphones (both magnetic and crystal, the latter
using the peizo-electric element from a cigarette lighter), etc.

'Instruments of Amplification', IMHO is the more interesting book. He
describes how to homebrew amplifying devices (not the circuits, which any
of us could make). The 'microphonic relay' (electromagnets coupled to a
carbon microphone-like thing), diode and triode valves (using filaments
taken from light bulbs, in case you're wondering), transisotrs
(point-contact ones using the crystal from a germanium diode, copper
oxide ones made the hard way), and so on.

Now, to be honext, the devices are terrible. If you want a triode to use,
go and buy am ECC83 / 12AX7. If you want a tranistor, go and get a
2N3904. It'll work a lot better, last a lot longer (his first home-made
valves had filament lifetimes of a few minutes, his transistors broke
down at a few volts), and be a lot cheaper.

But IMHO you'll lear a lot if you read said books, and even more if you
try to repeat and improve on the designs.

> an EPROM programmer. I build that kind of thing when I was a kid and I just
> don't see that I'd get anything out of building another one.

There's probably little point if you've already built at least one
programmer, or a similar insturment of similar complexity. But if you
haven't, then you should have a go. As I aid, you'll learn a lot, not
just about EPROMs...

I think the best way to sum it up is to quote from a book written nearly
100 years ago called 'Every Boy His Own Mechanic'. This chapter covers
making a simple telephone system

" For some years previous to 1914 the constructive instinct and ability
inherent in many of us was almost snuffed out because most of the
mechanical and electrical things we wished to possess were so cheap that
they could be bought ready made. Often the prices quoted were actually
below the cost to us of the raw materials, and so we came to think that
constructive hobbies were a bit futile. Lots of those cheap things were
amazingly good, but some where exasperatingly bad, and the bulk
indifferent. Still, we bought the stuff, learned nothing from it, and
clean missed all the solid satisfaction that lives for ever in building
and contriving and creating

Take the ready-made cheap telephone, for instance. How long did it take
to get fed up with ringing and asking "are you there ?" Was it really
worth the outlay of 15s to 45s? Frankly, no. Why? Because our purchase
locked us out from all the subtle mysteries of an ever-wonderful
instrument (simple though it may be), and we had been robbed of all the
joy of its making. If it failed to act we discovered that we could not
put it right. If it acted perfectly, we took the whole thing for granted
and soon became bored. But to build up that same installation oneself in
the face of difficulties from the homeliest of raw materials, and at last
to have it (in litteral fact) voicing our triumph in our eager-listening
ears - ah, that is a very different matter! "

And that's why I still homebrew stuff....

-tony
Received on Thu Jul 29 2004 - 19:04:22 BST