Re: hobby electronics

On 7/3/2024 2:30 AM, Martin Brown wrote:

There are still a few, but it has become a very minority interest today. Partly because everything is so heavily integrated and surface mount.

The other important issue you're forgetting is how *inexpensive* everything
(finished electronic product) is, today.
I love designing unique timepieces.  But, I can't beat the price of other
"unique" products on the market.  Why take on the effort if you're willing
to "settle" for something that you can buy for an hour's minimum wage pay?
Ans:  you need to be TRULY unique (I've designed a sundial with a regular
clock face -- 30 degrees per hour -- that keeps "perfect" time, even at
night!).

When I grew up you could get dead ICL 1900 boards full of TTL chips for and bags dross coated transistors at start of line for pennies. Today there is no equivalent source of cheap easily reused parts.

In school, I had access to the scrap pile at DEC Maynard.  In theory, ASSEMBLE
an 8, 10, 11, etc. from "discarded" pieces.  But, to what end?  Just to say
you have one in your dorm room?
A friend built (wire-wrap) a small 8080 system writing all the tools from
scratch, his own OS, applications, etc.  But, had access to a different
minicomputer with more ESTABLISHED capabilities in each of his classes.
I.e., there was no practical value to having his own computer.  And, as
it relied heavily on LSI for its functionality, it was essentially a
"plug together" system built out of modules called "chips".
OTOH, I recall designing a CDI for the car I was driving, at the time.  And,
experimenting with using the conventional ignition vs. the CDI to see if
any significant differences could be detected in performance, power, etc.
It got me interested in *non-electronic* aspects of automotive systems.

Back then there were also electronic kits for build your own computer etc.
 A lot of it today is plugging new mass produced modules together. Raspberry Pi has done a lot for that and to encourage electronics hobbyists though so it isn't all bad news.

Their attention turns to 3D printing cases for these sorts of things.
I saw a guy hack together (his interpretation of) a "tricorder" out of
COTS modules.  Likely more functional than the TV props but, beyond
the novelty, what value that a cell phone doesn't already have in a
bigger way?

Go looking at maker-spaces or whatever they are called in the US. Most of them will be trying to make electric guitars but they will be showing at least some skills with small pickup coils and low noise amplifiers.

Electric guitars (and 98+% of the effort will be in CAD, woodworking and
cosmetics), bicycles, other large steel assemblies (outdoor tables), furniture,
fountain pens, cabinetry to house MAME systems, etc.
But, very little "electronics from scratch" -- despite having a Metcal, Mantis,
assorted benchtop test gear and a huge selection of donated components.  The
bench always looks clear whenever I've been there.  *Maybe* someone uses it
to repair something "precious"?  But, it would truly have to BE precious to
find someone investing the time to repair vs. simply replacing (an excuse to
upgrade to a newer model).
I work with a few non-profits that recycle e-waste.  The quantities are
simply staggering!  And, much of it is fully operational at the time it is
"discarded".
[I've 30 (!) monitors on hand (three different sizes/models).  If/when one
shits the bed (I have 13 deployed), I swap it out for a spare and make a
note to repair it, later.  Likewise, the (1100W) power supplies in my
workstations have a unique form factor.  So, I have three spares on hand.
Why would I want to replace a PC just because its power supply died?  (I can
fix the dead one at my leisure)]
OTOH, neighbors simply drive out to one of the local stores (needn't even
be an "electronics" store!) and consider it par for the course.  You can buy
four or five 85 inch TVs (to use as monitors) for the price of my first PC!
So, what's to "save" by repair?

Back in my day a lot of our physics practicals were essentially electronics based - characteristics of a FET, various oscillators and a substantial digital electronics and logic course with a finishing test of making a digital dice (it may still be the same course even now).

We used to make decade counters out of DTL/RTL on perf-board.  They were more
exercises in "packaging" as you'd just keep adding "slices" to a multilayer
stack of small postage stamp sized subcircuits.  But, how many counters can
you actually make use of?
As a young kid, my uncles wanted to lay claim to some semi trailers that had
been parked on their (business) property for several years.  They contained
the pin-setters that had been removed from a nearby bowling alley that had gone
tits up.  Wrap a steel cable around the wooden skid under each pin-setter,
tie to rear bumper of a truck, drag skid out of trailer and let it crash
to the ground.  (!) I went hog-wild salvaging relays and mechanisms from them
and repurposing for other projects, at home.  But, there were no commercial
alternatives to the things that I was making, at the time (digital locks,
games, clocks, etc).

I'm pretty sure the previous generation did the same experiments on thermionic valves and relays but that was discontinued on H&S grounds.