Digital Television DTV

[Joerg]

Hi Terry,

Holden had a dreadful run just recently in Australia - dodgy car computers.
Cars would do things like refuse to unlock, or start etc. when T got too
high - as it tends to in the outback. Ya cant crash-start them new-fangled
gizmos.

It's not just Holden. There are some European cars that have over 50
micro controllers in them. You won't see me buy one of these. And the
fact that a dealer's tech can't find a broken ULN2003 doesn't surprise
me. They were not trained as electronics technicians. I remember a
friend who had to wait two weeks because the only tech that knew this
controller stuff was on vacation. I bet this tech makes a ton of money.
Or at least could.

when I lived in the US ('97-2000) there was much discuccion about so-called
self-adjusting clocks - they use a time signal that is broadcast along with
the content. Problem was, if a west-coast show was played on the east coast,
and the service provider didnt strip the "old" timestamp and replace it with
the correct one, VCRs automatically re-set their clocks. And you cant stop
them doing it....exactly the sort of so-called "brilliance" I expect from
software - the idea is great, but the implementation aint.

That's because the system seems ill conceived. Why wasn't one more byte
transmitted that would indicate PST, CST and EST? I just don't get it
how such simple tasks can be botched. Or just transmit universal time
(UTC). The military has no problem with time stamping. Never had,
because they know how to do it right. Same for air traffic control.
Sometimes design engineers ought to swallow their pride and look over
the fence.

Mind you, I once wrote an astonishingly lazy program in matlab. I was
re-engineering smt resistors for a new product (our prod guys said we could
have as many values as we wanted, so we did. Then they changed their mind).
For each R I used R||R||(R+R) from a very limited set. To pick the "best"
network for each R, I basically calculated every combination of the values
at hand, for each of the 4 topologies, then sorted the results for each
topology in descending order of accuracy. Listing the top 10 results for
each topology I could thus pick the best combination. Of course my PC did a
few billion calculations to choose 100 "new" resistors, but who cares

Here's how I still do that: With a slide rule. Works in odd locations,
no power, high winds, whatever. Multi-purpose design allows it to also
measure lengths, cut bread if needed. PVC construction allows to move HV
probes around with it safely. Continuous memory as long as you don't
drop it, no batteries. But you will be exposed to mockery: Once on a
contract job in a high tech company I came back to my prototype bench
only to find droves of engineers around it. They were all staring at my
slide rule. None of them was able to figure even an RC constant with it.
But nevertheless they reminded me that this company was equipped with
electric light and I would not have to bring in a kerosene lamp.

Regards, Joerg

 

[Terry Given]

Hi Joerg,

Hi Terry,

It's not just Holden. There are some European cars that have over 50
micro controllers in them. You won't see me buy one of these. And the
fact that a dealer's tech can't find a broken ULN2003 doesn't surprise
me. They were not trained as electronics technicians. I remember a
friend who had to wait two weeks because the only tech that knew this
controller stuff was on vacation. I bet this tech makes a ton of money.
Or at least could.

you are not wrong. I once made an easy $1,000 by fixing a fuel injection
controller for a large boat. I repaired videogames for the owner, who had
been told to replace the $3,000 controller, by the service agents. I pulled
it apart (before I was an EE , found a 555 timer configured as an
oscillator that didnt, and replaced it. total cost of repair $0.50 for the
555 timer, $10 for a can of plasti-cote and 1/2 hour labour. Ken was
overjoyed to get it back for $1,000 - we had agreed on the price before I
looked at it, as I figured it would probably be a real pig to fix. I didnt
tell him how easy it was though....

there is certainly money to be made in such non-traditional areas. By the
same token, my next car will be one I can repair myself....

That's because the system seems ill conceived. Why wasn't one more byte
transmitted that would indicate PST, CST and EST? I just don't get it
how such simple tasks can be botched. Or just transmit universal time
(UTC). The military has no problem with time stamping. Never had,
because they know how to do it right. Same for air traffic control.
Sometimes design engineers ought to swallow their pride and look over
the fence.

I think the root cause here is failure to investigate potential problems -
the "what happens if X goes wrong" scenario. If you make mil stuff, you HAVE
to do it - FMECA etc. most software "engineers" (I dont think they deserve
the title) dont seem to think about how to prove their stuff works at all,
let alone what happens when things go wrong. quality people have the
Plan-Do-Check-Act mantra, which IMO is a great plan. wrap feedback loops
around things, then regulate problems out.

Here's how I still do that: With a slide rule. Works in odd locations,
no power, high winds, whatever. Multi-purpose design allows it to also
measure lengths, cut bread if needed. PVC construction allows to move HV
probes around with it safely. Continuous memory as long as you don't
drop it, no batteries. But you will be exposed to mockery: Once on a
contract job in a high tech company I came back to my prototype bench
only to find droves of engineers around it. They were all staring at my
slide rule. None of them was able to figure even an RC constant with it.
But nevertheless they reminded me that this company was equipped with
electric light and I would not have to bring in a kerosene lamp.

Regards, Joerg

I dont have a slide rule, but I do most of my maths by hand (a-la slide rule
. Especially figuring out orders of magnitude - helps to detect screw-ups.

In this particular case I had to re-design about 250 resistor values, so
took the lazy approach. We had decided on 1, 3.3 and 4.7 per decade for
resistors, and this way I got to do some real work whilst HAL9000 chundered
away at the boring stuff. I spent about 10 minutes writing the matlab
function, and about 15 minutes (over about 3 hours) asking for various
combinations.

If I ever see one I will buy it - what should I look for?

Cheers
Terry

 

[Joerg]

Hi Terry,

I think the root cause here is failure to investigate potential problems -
the "what happens if X goes wrong" scenario. If you make mil stuff, you HAVE
to do it - FMECA etc. most software "engineers" (I dont think they deserve
the title) dont seem to think about how to prove their stuff works at all,
let alone what happens when things go wrong. quality people have the
Plan-Do-Check-Act mantra, which IMO is a great plan. wrap feedback loops
around things, then regulate problems out.

That is a good point you bring up. I am very used to a hazard analysis
because I am often involved in med electronics. Everything needs to be
analyzed, single fault hazards, double-fault, mitigation and so on. No
stone is left unturned. After that UL and TUEV have at it and dissect
everything. And they should. I have never complained when others thought
they are too picky. There is just too much at stake. Unfortunately this
thinking doesn't always make it into other safety critical areas such as
cars. Just imagine buzzing alone in the fast lane when one of the
gazillion micro controllers gives up. A friend once heard a gentle
"click" from the steering column while doing 60mph or so. The theft lock
had engaged and disabled the steering wheel...

Unfortunately sound engineering techniques are hardly taught at a
university. Ours did but it was meant for mech engineers. So I snuck in
and got a bruise when they found out I was not one of them. But it
taught me about dynamic stress failures and all that stuff. I am amazed
how many engineers just design a large heat sink onto a board,
precariously held by some teeny #4 screws. No washers, no lock washers,
nada.

I dont have a slide rule, but I do most of my maths by hand (a-la slide rule
. Especially figuring out orders of magnitude - helps to detect screw-ups.

In this particular case I had to re-design about 250 resistor values, so
took the lazy approach. We had decided on 1, 3.3 and 4.7 per decade for
resistors, and this way I got to do some real work whilst HAL9000 chundered
away at the boring stuff. I spent about 10 minutes writing the matlab
function, and about 15 minutes (over about 3 hours) asking for various
combinations.

If I ever see one I will buy it - what should I look for?

Yes, I also did the PC thing a couple times when sloshing tons of part
values for multi-order elliptic filters and stuff like that. Try the
MS-Works spread sheet, it comes with most PCs so there is no added
expense and it is pretty fast. I think even a PDA can do that nowadays.

Slide rule: While it's nice to have an EE version these are hard to come
by and expensive. I do have one but it was a paper freebie from Shure.
It has suffered some during an Atlantic Ocean trip. Other than that a
Melamine (maybe called different in NZ) version is nice because that
stuff is fairly scratch and heat resistant in case it is left in the car
in summer. Then I gently "grease" the slider with a tiny bit of soap.
That works like overclocking on the old PCs.

Regarding buying only cars you can repair yourself: I guess that is why
National's Bob Pease stubbornly clings to the VW Beetle. The old
version, of course. I still think back to my Citroen 2CV, a whopping 16
horses and no electronics. Not even a diode, zilch. It never let me down.

Regards, Joerg

 

[Jan Panteltje]

I am amazed
how many engineers just design a large heat sink onto a board,
precariously held by some teeny #4 screws. No washers, no lock washers,
nada.

Are they not all glued on in mil spec equipment these days ;-)?

I still think back to my Citroen 2CV, a whopping 16
horses and no electronics. Not even a diode, zilch. It never let me down.

The windows would not lock and flap open at 100km/h and 10 below zero
in the one I tried....
Maintenance 'what is that?'.
JP

 

[Joerg]

Hi Jan

The windows would not lock and flap open at 100km/h and 10 below zero
in the one I tried....
Maintenance 'what is that?'.

The 16 horsepower version never made it to 100km/h (65mph), not even
with a stiff breeze from behind. But it got better gas mileage than all
these newfangled small cars.

Also, the "maintenance procedure" for a non-closing window on these is
simple. With the window open you take a small piece of wood and slap it
onto the little snap hook that holds the window.

Maintenance on these cars was so easy. Three screws and the fender came
off. Then I'd let half the air out of the tire so sitting on it is more
comfortable. You could adjust valves, brakes, everything from that
position. The air filter cap had an indentation that snugly held a
Grolsch beer bottle. What more can one wish for?

Regards, Joerg

 

[Jan Panteltje]

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Hi Jan

The 16 horsepower version never made it to 100km/h (65mph), not even
with a stiff breeze from behind. But it got better gas mileage than all
these newfangled small cars.

You could be right, and long time ago, but soembody worked on that,
maybe it was 80.

Also, the "maintenance procedure" for a non-closing window on these is
simple. With the window open you take a small piece of wood and slap it
onto the little snap hook that holds the window.

Yea
The gear shift was a strange peculiar thingy too, although I also had
a peugot, with the gear handle on the steering wheel, so used to fun.

Maintenance on these cars was so easy. Three screws and the fender came
off. Then I'd let half the air out of the tire so sitting on it is more
comfortable. You could adjust valves, brakes, everything from that
position.

Maintenace? I never did that, it was not mine but the 'companies'
They did no maintence either, hence the windows.
My own nissan I have taken apart, replaced head sealing, stuff like that.


The air filter cap had an indentation that snugly held a

Grolsch beer bottle. What more can one wish for? Mercedes?

Regards, Joerg

I like the ferrari models too
JP


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