And to think I used to do this for a living...
My Pi ZERO W heating controller is alive, but it took some forceps...

First Problem:

Not all transistors are created equal. I used obsolete transistors that
I used to use years ago - BC182... but they didn't work. Turns out
today's BC182 has a different pinout from what I was used to - *BC182L*
was the solution. That worked.

Second Problem:

Pi connectors. I bought kit to make up Pi female connectors to go from
the pins on one board to pins on another. I wasted a whole day and a
half and was completely unable to make a satisfactory lead up , either
by crimping or by soldering.
Gave up and bought jumper leads.

Third problem:

All earths are not created equal. I wanted to use a 5 way connector to
pins 31,33,35,37 with pin 39 as power and signal earth on the Pi Zero W.

I don't know what pin 39 is connected to, but it sure ain't earth. maybe
via a high resistance, but not enough to power a Pi. I used pin 6, and
that worked...

There are still some software issues to resolve, but the unit now has a
nice 3D printed case and the relays all click and the LEDs all light...

*phew*.

http://vps.templar.co.uk/Odds%20and%20Ends/BCD_0027.JPG
http://vps.templar.co.uk/Odds%20and%20Ends/BCD_0026.JPG

--
It is the folly of too many to mistake the echo of a London coffee-house
for the voice of the kingdom.

Jonathan Swift

The Natural Philosopher wrote:

> the unit now has a nice 3D printed case
> http://vps.templar.co.uk/Odds%20and%20Ends/BCD_0026.JPG

If your friend can enable monotonic infill, it would avoid those
diagonal stripes where it navigates around the LED holes ...

On 25/10/2023 14:49, Andy Burns wrote:
> The Natural Philosopher wrote:
>
>> the unit now has a nice 3D printed case
>> http://vps.templar.co.uk/Odds%20and%20Ends/BCD_0026.JPG
>
> If your friend can enable monotonic infill, it would avoid those
> diagonal stripes where it navigates around the LED holes ...

I will shortly be getting my own printer. I would appreciate any tips
like these you can give me!

--
"Socialist governments traditionally do make a financial mess. They
always run out of other people's money. It's quite a characteristic of them"

Margaret Thatcher

The Natural Philosopher <tnp@invalid.invalid> wrote:
>
> Pi connectors. I bought kit to make up Pi female connectors to go from
> the pins on one board to pins on another. I wasted a whole day and a
> half and was completely unable to make a satisfactory lead up , either
> by crimping or by soldering.
> Gave up and bought jumper leads.

If they were ribbon cable connectors then I can understand that -
you really want the proper tool for pushing those together when
they're that wide.

I've got a bag full of old PC IDE cables, so it's easy just to
attack one of those instead because they're also 40 pin.

> All earths are not created equal. I wanted to use a 5 way connector to
> pins 31,33,35,37 with pin 39 as power and signal earth on the Pi Zero W.
>
> I don't know what pin 39 is connected to, but it sure ain't earth. maybe
> via a high resistance, but not enough to power a Pi. I used pin 6, and
> that worked...

Pin 6 might just be connected by a tiny little track on the Pi
Zero's PCB because it's only supposed to be a signal ground. I go
to the trouble of grounding all the ground pins on the GPIO. But
just for driving relays I guess you can cut some corners, just
not too many apparantly.

--
__ __
#_ < |\| |< _# | Note: I won't see posts made from Google Groups |

On 10/25/23 8:57 AM, The Natural Philosopher wrote:
> And to think I used to do this for a living...
> My Pi ZERO W heating controller is alive, but it took some forceps...
>
> First Problem:
>
> Not all transistors are created equal. I used obsolete transistors that
> I used to use years ago - BC182... but they didn't work.  Turns out
> today's BC182 has a different pinout from what I was used to - *BC182L*
> was the solution. That worked.

IF possible, stick to super-popular "legacy" transistors.
2n2222 are very versatile, 3809s are ok if you don't need
to handle much power.

There are some 'logic level' MOSFET-family out there that
are very good for higher power levels. Again, stick to the
classics if possible.

>
> Second Problem:
>
> Pi connectors. I bought kit to make up Pi female connectors to go from
> the pins on one board to pins on another. I wasted a whole day and a
> half  and was completely unable to make a satisfactory lead up ,  either
> by crimping or by soldering.
> Gave up and bought jumper leads.

'Connections' ALWAYS seem to be an unnecessary bitch.

> Third problem:
>
> All earths are not created equal. I wanted to use a 5 way connector to
> pins 31,33,35,37 with pin 39 as power and signal  earth on the Pi Zero W.

Heh, heh ... yep, 'earths' are NOT all created equal.
Look into RS-4xx data connections for fun ... some
'earths' can cause HUGE DEADLY current flow :-)u

Clue, two "ground" connections even 500-1000 feet
apart are NOT gonna be at the same potential. Oft
wondered if you can get actual usable power from
that ...... can 0.25 volts dif, at a potential
100-1000 amps, be converted to higher voltage/
lower amps these days ?

> I don't know what pin 39 is connected to, but it sure ain't earth. maybe
> via a high resistance, but not enough to power a Pi. I used pin 6, and
> that worked...

The 7th pin, on the top edge, is a fairly reliable ground.
Be cautious otherwise unless it's something stupid like
powering a fan.

> There are still some software issues to resolve, but the unit now has a
> nice 3D printed case and the relays all click and the LEDs all light...
>
> *phew*.
>
> http://vps.templar.co.uk/Odds%20and%20Ends/BCD_0027.JPG
> http://vps.templar.co.uk/Odds%20and%20Ends/BCD_0026.JPG

I'm slowly putting together a home-security system
with all the goodies - including opto-isolated
inputs. It is gonna run on a Pi4 or now maybe on
a Pi5, sporting a usable web interface. Switches,
detectors, video ... all in one.

The Natural Philosopher wrote:

> I bought kit to make up Pi female connectors to go from the pins on one
> board to pins on another. I wasted a whole day and a half  and was
> completely unable to make a satisfactory lead up ,  either by crimping
> or by soldering.
> Gave up and bought jumper leads.

Don't think I'd trust a bunch of DuPont wires long term ... at least hot
snot them in place.

On 26/10/2023 05:27, 56d.1152 wrote:
> On 10/25/23 8:57 AM, The Natural Philosopher wrote:
>> And to think I used to do this for a living...
>> My Pi ZERO W heating controller is alive, but it took some forceps...
>>
>> First Problem:
>>
>> Not all transistors are created equal. I used obsolete transistors
>> that I used to use years ago - BC182... but they didn't work.  Turns
>> out today's BC182 has a different pinout from what I was used to -
>> *BC182L* was the solution. That worked.
>
>   IF possible, stick to super-popular "legacy" transistors.
>   2n2222 are very versatile, 3809s are ok if you don't need
>   to handle much power.
>
>   There are some 'logic level' MOSFET-family out there that
>   are very good for higher power levels. Again, stick to the
>   classics if possible.
>
>>
>> Second Problem:
>>
>> Pi connectors. I bought kit to make up Pi female connectors to go from
>> the pins on one board to pins on another. I wasted a whole day and a
>> half  and was completely unable to make a satisfactory lead up ,
>> either by crimping or by soldering.
>> Gave up and bought jumper leads.
>
>
>   'Connections' ALWAYS seem to be an unnecessary bitch.
>
>
>> Third problem:
>>
>> All earths are not created equal. I wanted to use a 5 way connector to
>> pins 31,33,35,37 with pin 39 as power and signal  earth on the Pi Zero W.
>
>   Heh, heh ... yep, 'earths' are NOT all created equal.
>   Look into RS-4xx data connections for fun ... some
>   'earths' can cause HUGE DEADLY current flow  :-)u
>
>   Clue, two "ground" connections even 500-1000 feet
>   apart are NOT gonna be at the same potential. Oft
>   wondered if you can get actual usable power from
>   that ...... can 0.25 volts dif, at a potential
>   100-1000 amps, be converted to higher voltage/
>   lower amps these days ?
>
>
>> I don't know what pin 39 is connected to, but it sure ain't earth.
>> maybe via a high resistance, but not enough to power a Pi. I used pin
>> 6, and that worked...
>
>   The 7th pin, on the top edge, is a fairly reliable ground.
>   Be cautious otherwise unless it's something stupid like
>   powering a fan.
>
>> There are still some software issues to resolve, but the unit now has
>> a nice 3D printed case and the relays all click and the LEDs all light...
>>
>> *phew*.
>>
>> http://vps.templar.co.uk/Odds%20and%20Ends/BCD_0027.JPG
>> http://vps.templar.co.uk/Odds%20and%20Ends/BCD_0026.JPG
>
>   I'm slowly putting together a home-security system
>   with all the goodies - including opto-isolated
>   inputs. It is gonna run on a Pi4 or now maybe on
>   a Pi5, sporting a usable web interface. Switches,
>   detectors, video ... all in one.
>
>
Good project.

I have all the wiring here for a home security system but I never
installed one because I retired at that point and the house was never empty

--
“Puritanism: The haunting fear that someone, somewhere, may be happy.”

H.L. Mencken, A Mencken Chrestomathy

On 26/10/2023 08:30, Andy Burns wrote:
> The Natural Philosopher wrote:
>
>> I bought kit to make up Pi female connectors to go from the pins on
>> one board to pins on another. I wasted a whole day and a half  and was
>> completely unable to make a satisfactory lead up ,  either by crimping
>> or by soldering.
>> Gave up and bought jumper leads.
>
> Don't think I'd trust a bunch of DuPont wires long term ... at least hot
> snot them in place.

Used 100% to connect model plane servos. They are pretty good. That
units going to be screwed onto a wall and never moved again.

I might add a zip tie or two.

I wouldn't trust it in a car though - there I would follow your advice

--
"And if the blind lead the blind, both shall fall into the ditch".

Gospel of St. Mathew 15:14

In message <65398740@news.ausics.net>
not@telling.you.invalid (Computer Nerd Kev) wrote:

> The Natural Philosopher <tnp@invalid.invalid> wrote:
> >
> > Pi connectors. I bought kit to make up Pi female connectors to go from
> > the pins on one board to pins on another. I wasted a whole day and a
> > half and was completely unable to make a satisfactory lead up , either
> > by crimping or by soldering. Gave up and bought jumper leads.
>
> If they were ribbon cable connectors then I can understand that - you
> really want the proper tool for pushing those together when they're that
> wide.

I've found it not too difficult to do ribbon insulation displacement
cables if you have a vice, but the caveats I can think of are:

Use a VERY sharp pair of scissors to cut the cable. If it isn't cut
cleanly, there may be little bits of copper core hanging out, just
waiting to short to a neighbour. (Been there.)

Connectors need to be crunched on at very close to 90 degrees to the
cable. It's surprising how little margin for error there is, or else
there may be shorts between adjacent cores.

The vice's jaws need to cover the whole connector and to close parallel.
If the jaw surfaces are serrated, some dense cardboard may help, but you
will need them held in place simply to avoid having to keep so many bits
all in the right place as you tighten the vice.

David

On Thu, 26 Oct 2023 16:16:33 +0100, David Higton wrote:

> In message <65398740@news.ausics.net>
> not@telling.you.invalid (Computer Nerd Kev) wrote:
>
>> The Natural Philosopher <tnp@invalid.invalid> wrote:
>> >
>> > Pi connectors. I bought kit to make up Pi female connectors to go
>> > from the pins on one board to pins on another. I wasted a whole day
>> > and a half and was completely unable to make a satisfactory lead up
>> > , either by crimping or by soldering. Gave up and bought jumper
>> > leads.
>>
>> If they were ribbon cable connectors then I can understand that - you
>> really want the proper tool for pushing those together when they're
>> that wide.
>
> I've found it not too difficult to do ribbon insulation displacement
> cables if you have a vice, but the caveats I can think of are:
>
> Use a VERY sharp pair of scissors to cut the cable. If it isn't cut
> cleanly, there may be little bits of copper core hanging out, just
> waiting to short to a neighbour. (Been there.)
>
> Connectors need to be crunched on at very close to 90 degrees to the
> cable. It's surprising how little margin for error there is, or else
> there may be shorts between adjacent cores.
>
> The vice's jaws need to cover the whole connector and to close parallel.
> If the jaw surfaces are serrated, some dense cardboard may help, but you
> will need them held in place simply to avoid having to keep so many bits
> all in the right place as you tighten the vice.
>
Curiosity: would it help to use one of the spray-on contact cements or one
of the cyanoacrylates (e.g. Zap) to hold things in place while they're in
the vice?

--

Martin | martin at
Gregorie | gregorie dot org

On Wed, 25 Oct 2023 15:51:12 +0100
The Natural Philosopher <tnp@invalid.invalid> wrote:

> I will shortly be getting my own printer. I would appreciate any tips
> like these you can give me!

I have a few :) You may know some of this.

This one is really important - when you open a reel of filament you
will find that the end is clipped in place or fed through holes in the
sides. Once you release it DO NOT LET GO of it, not even for an instant,
until it is securely fixed in the printer's feed mechanism. If the filament
ever springs back onto the roll it WILL tangle (Sod's law applies) and then
it will jam during a print ruining the print - usually after hours of
printing.

All printing filaments are hygroscopic and need to be protected
from humidity. Vacuum bags are essential and a drying box is useful.

When choosing a printer to buy make sure that you understand how
the bed levelling process works and that you are satisfied that it is
effective and reliable - bed levelling is the single most important thing
to get right before printing.

FWIW I currently have a FlashForge Creator Pro and am reasonably
happy with it (it certainly isn't perfect and there are many equally good
and better options - oh and worse too) - next time I feel like spending
money on a printer it will be one of these (no connection I just like the
design and reviews):

https://ratrig.com/3d-printers/rat-rig-kits.html.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/
Host: Beautiful Theory meet Inconvenient Fact
Obit: Beautiful Theory died today of factual inconsistency

On 25/10/2023 15:51, The Natural Philosopher wrote:
> On 25/10/2023 14:49, Andy Burns wrote:
>> The Natural Philosopher wrote:
>>
>>> the unit now has a nice 3D printed case
>>> http://vps.templar.co.uk/Odds%20and%20Ends/BCD_0026.JPG
>>
>> If your friend can enable monotonic infill, it would avoid those
>> diagonal stripes where it navigates around the LED holes ...
>
> I will shortly be getting my own printer. I would appreciate any tips
> like these you can give me!
>

Look on Tom's Hardware.
https://www.tomshardware.com/best-picks/best-3d-printers

--
Chris Elvidge, England
I WILL NOT YELL "SHE'S DEAD" DURING ROLL CALL

On 10/26/23 4:12 AM, The Natural Philosopher wrote:
> On 26/10/2023 05:27, 56d.1152 wrote:
>> On 10/25/23 8:57 AM, The Natural Philosopher wrote:
>>> And to think I used to do this for a living...
>>> My Pi ZERO W heating controller is alive, but it took some forceps...
>>>
>>> First Problem:
>>>
>>> Not all transistors are created equal. I used obsolete transistors
>>> that I used to use years ago - BC182... but they didn't work.  Turns
>>> out today's BC182 has a different pinout from what I was used to -
>>> *BC182L* was the solution. That worked.
>>
>>    IF possible, stick to super-popular "legacy" transistors.
>>    2n2222 are very versatile, 3809s are ok if you don't need
>>    to handle much power.
>>
>>    There are some 'logic level' MOSFET-family out there that
>>    are very good for higher power levels. Again, stick to the
>>    classics if possible.
>>
>>>
>>> Second Problem:
>>>
>>> Pi connectors. I bought kit to make up Pi female connectors to go
>>> from the pins on one board to pins on another. I wasted a whole day
>>> and a half  and was completely unable to make a satisfactory lead up
>>> , either by crimping or by soldering.
>>> Gave up and bought jumper leads.
>>
>>
>>    'Connections' ALWAYS seem to be an unnecessary bitch.
>>
>>
>>> Third problem:
>>>
>>> All earths are not created equal. I wanted to use a 5 way connector
>>> to pins 31,33,35,37 with pin 39 as power and signal  earth on the Pi
>>> Zero W.
>>
>>    Heh, heh ... yep, 'earths' are NOT all created equal.
>>    Look into RS-4xx data connections for fun ... some
>>    'earths' can cause HUGE DEADLY current flow  :-)u
>>
>>    Clue, two "ground" connections even 500-1000 feet
>>    apart are NOT gonna be at the same potential. Oft
>>    wondered if you can get actual usable power from
>>    that ...... can 0.25 volts dif, at a potential
>>    100-1000 amps, be converted to higher voltage/
>>    lower amps these days ?
>>
>>
>>> I don't know what pin 39 is connected to, but it sure ain't earth.
>>> maybe via a high resistance, but not enough to power a Pi. I used pin
>>> 6, and that worked...
>>
>>    The 7th pin, on the top edge, is a fairly reliable ground.
>>    Be cautious otherwise unless it's something stupid like
>>    powering a fan.
>>
>>> There are still some software issues to resolve, but the unit now has
>>> a nice 3D printed case and the relays all click and the LEDs all
>>> light...
>>>
>>> *phew*.
>>>
>>> http://vps.templar.co.uk/Odds%20and%20Ends/BCD_0027.JPG
>>> http://vps.templar.co.uk/Odds%20and%20Ends/BCD_0026.JPG
>>
>>    I'm slowly putting together a home-security system
>>    with all the goodies - including opto-isolated
>>    inputs. It is gonna run on a Pi4 or now maybe on
>>    a Pi5, sporting a usable web interface. Switches,
>>    detectors, video ... all in one.
>>
>>
> Good project.

It's fun - AND very useful. I've been making progress,
but I'll have more time when fully retired. Recently
picked up a multi-relay board meant for a Beaglebone
Black - but adaptable. Perfect for alarm sounders
and even turning on room lights. Sometimes you need
AMPERAGE.

Retiring, I need to know what's going bump in
the night AND be able to see/know what's going
on when I'm not home. Do NOT trust commercial
providers one bit. So ...

Look into the popular commercial alarm systems.
I think the Honeywell/Ademco ones are the most
popular. They're incredibly versatile, but they
employ HORRIBLE programming approaches oriented
around terminals with like 25x2 or 25x4 LED
displays. It's clunkier than a FORTH pgm, and
I speak from experience. A proper, if simple,
web interface is THE way to go. Been there, done
those, so ....

Let my tombstone read "I did it MY way" :-)

Ok, what's it cost these days to be deep-frozen,
$300k ??? Kinda like the lottery, if you DON'T
play you CAN'T win ..........

> I have all the wiring here for a home security system but I never
> installed one because I retired at that point and the house was never empty

Yea, but SOMETIMES you have to go away, even if
to a stupid dental appt. It'd be nice to have a
system where you COULD be informed of odd goings-on.
Easy these days to send a text over the web.

Alas, actual "human-form detection" worth a crap is
still kinda the realm of boards much more powerful
than any Pi. Yea, yea, some packages, even cams,
CLAIM to offer something like that, but read the
fine print. 95+ percent of your 'positives' are gonna
be FALSE. A bush in the wind WILL kinda emulate a
human-form pattern a dozen times a day. Seen it.

The only thing worse than a false negative are lots
of false positives. Hey, WAY back in the day, I
remember when the public schools decided to have
the cops bring sniffer dogs to find lockers that
smelled like reefer. So, the potheads made a point
to put a little reefer dust and/or roaches in the
lockers of the Honor Roll students. The program
was terminated immediately :-)

On 10/26/23 4:16 AM, The Natural Philosopher wrote:
> On 26/10/2023 08:30, Andy Burns wrote:
>> The Natural Philosopher wrote:
>>
>>> I bought kit to make up Pi female connectors to go from the pins on
>>> one board to pins on another. I wasted a whole day and a half  and
>>> was completely unable to make a satisfactory lead up ,  either by
>>> crimping or by soldering.
>>> Gave up and bought jumper leads.
>>
>> Don't think I'd trust a bunch of DuPont wires long term ... at least
>> hot snot them in place.
>
> Used 100% to connect model plane servos. They are pretty good. That
> units going to be screwed onto a wall and never moved again.
>
> I might add a zip tie or two.
>
> I wouldn't trust it in  a car though - there I would follow your advice

Solder IS the best.

But, remember "wire wrap" ? Still have the tools
for doing that. The more-extensive wrapping CAN
be as reliable as soldered connections.

On 27/10/2023 04:44, 56d.1152 wrote:

>
>   Solder IS the best.
>
No, actually it often isn't...

The problem with solder on *stranded* wire is that it wicks up the wire
and reduces it's flexibility by binding the strands together: That
creates a stress concentration where it stops and a likely cause of
fracture failure under vibration. That is why crimps are the choice for
cheaper connections in high stress environments (e.g. automotive) or if
you must solder you absolutely need to mechanically support the wire
upstream of the solder joint.

>   But, remember "wire wrap" ?

I was trained, as an apprentice, on military spec hardware construction:
Wire wrap was one system that was used extensively in early digital
hardware backplane prototyping.

Once the design was stabilised they tended to replace all that with a 2
layer PCB.

> Still have the tools
>   for doing that. The more-extensive wrapping CAN
>   be as reliable as soldered connections.

Yes. especially in high vibration environments where components are not
mechanically connected except by their leads or pins.

--
"Anyone who believes that the laws of physics are mere social
conventions is invited to try transgressing those conventions from the
windows of my apartment. (I live on the twenty-first floor.) "

Alan Sokal

On Thu, 26 Oct 2023 23:44:48 -0400
"56d.1152" <56d.1152@ztq9.net> wrote:

> But, remember "wire wrap" ? Still have the tools
> for doing that. The more-extensive wrapping CAN
> be as reliable as soldered connections.

A good wire wrap connection (done with a power tool - we always
used Gardner-Denver) is gas tight and extremely reliable as well as being
faster and easier to modify than soldering.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/
Host: Beautiful Theory meet Inconvenient Fact
Obit: Beautiful Theory died today of factual inconsistency

On 27 Oct 2023 at 05:32:34 BST, "The Natural Philosopher"
<tnp@invalid.invalid> wrote:

>> But, remember "wire wrap" ?
>
> I was trained, as an apprentice, on military spec hardware construction:
> Wire wrap was one system that was used extensively in early digital
> hardware backplane prototyping.
>
> Once the design was stabilised they tended to replace all that with a 2
> layer PCB.
>
>> Still have the tools for doing that. The more-extensive wrapping CAN
>> be as reliable as soldered connections.
>
> Yes. especially in high vibration environments where components are not
> mechanically connected except by their leads or pins.

I was told, back in the day, that it's more reliable. Many mainframes had
wire-wrapped backplanes. I recall seeing engineers come in during maintenance
time to replace wires due to upgrades or bug fixes; their being wire-wrapped
made it rather easier.

--
Tim

On 27 Oct 2023 09:29:03 GMT, TimS wrote:

> I was told, back in the day, that it's more reliable. Many mainframes
> had wire-wrapped backplanes. I recall seeing engineers come in during
> maintenance time to replace wires due to upgrades or bug fixes; their
> being wire-wrapped made it rather easier.
>
If you can find a copy, Tracey Kidder's book "The Soul of a New Machine"
is a nice read. He is a professional writer who was embedded in the team
who designed and built the prototype Data General 'Eagle's. This was one
of the first 32 bit minicomputer systems. Both prototypes were constructed
as wire-wrapped frames.

--

Martin | martin at
Gregorie | gregorie dot org

In message <uhe2l8$1mm2q$1@dont-email.me>
Martin Gregorie <martin@mydomain.invalid> wrote:

> On Thu, 26 Oct 2023 16:16:33 +0100, David Higton wrote:
>
> > In message <65398740@news.ausics.net>
> > not@telling.you.invalid (Computer Nerd Kev) wrote:
> >
> > > The Natural Philosopher <tnp@invalid.invalid> wrote:
> > > >
> > > > Pi connectors. I bought kit to make up Pi female connectors to go
> > > > from the pins on one board to pins on another. I wasted a whole day
> > > > and a half and was completely unable to make a satisfactory lead up
> > > > , either by crimping or by soldering. Gave up and bought jumper
> > > > leads.
> > >
> > > If they were ribbon cable connectors then I can understand that - you
> > > really want the proper tool for pushing those together when they're
> > > that wide.
> >
> > I've found it not too difficult to do ribbon insulation displacement
> > cables if you have a vice, but the caveats I can think of are:
> >
> > Use a VERY sharp pair of scissors to cut the cable. If it isn't cut
> > cleanly, there may be little bits of copper core hanging out, just
> > waiting to short to a neighbour. (Been there.)
> >
> > Connectors need to be crunched on at very close to 90 degrees to the
> > cable. It's surprising how little margin for error there is, or else
> > there may be shorts between adjacent cores.
> >
> > The vice's jaws need to cover the whole connector and to close parallel.
> > If the jaw surfaces are serrated, some dense cardboard may help, but you
> > will need them held in place simply to avoid having to keep so many bits
> > all in the right place as you tighten the vice.
> >
> Curiosity: would it help to use one of the spray-on contact cements or one
> of the cyanoacrylates (e.g. Zap) to hold things in place while they're in
> the vice?

Dunno. I was thinking more of double sided tape.

David

On 25/10/2023 3:51 pm, The Natural Philosopher wrote:
>
> I will shortly be getting my own printer. I would appreciate any tips
> like these you can give me!
>
I use octoprint (octoprint.org) on a Pi 2 I had lying about.

To design items I use tinkercad.com. If you already know about CAD use
whatever you're familiar with. I was 77 when I started and this was
adequate.

Pass the designed object (.stl file) to prusa slicer:

https://github.com/prusa3d/PrusaSlicer/releases

and then to octopi.

Adhesion of the object to the print bed is THE major problem, too lttle
adhesion and the print WILL at some stage float off the bed, too much
adhesion and it will be impossible to remove from the surface. I use a
magnetic layer, you remove it from the bed and bend it to remove the print.

The instructions will say use a sheet of paper to set the nozzle height.
Use a 0.30mm feeler gauge.

If you intend to print gears or pulleys come back to me.

If you're prone to frustration take a tranquiliser before you start.

Good luck

Another Dave

--
Change nospam to techie

On 27/10/2023 17:01, Another Dave wrote:
> On 25/10/2023 3:51 pm, The Natural Philosopher wrote:
>>
>> I will shortly be getting my own printer. I would appreciate any tips
>> like these you can give me!
>>
> I use octoprint (octoprint.org) on a Pi 2 I had lying about.
>
> To design items I use tinkercad.com. If you already know about CAD use
> whatever you're familiar with. I was 77 when I started and this was
> adequate.
>
> Pass the designed object (.stl file) to prusa slicer:
>
> https://github.com/prusa3d/PrusaSlicer/releases
>
> and then to octopi.
>
> Adhesion of the object to the print bed is THE major problem, too lttle
> adhesion and the print WILL at some stage float off the bed, too much
> adhesion and it will be impossible to remove from the surface. I use a
> magnetic layer, you remove it from the bed and bend it to remove the print.
>
> The instructions will say use a sheet of paper to set the nozzle height.
> Use a 0.30mm feeler gauge.
>
> If you intend to print gears or pulleys come back to me.
>
> If you're prone to frustration take a tranquiliser before you start.
>
> Good luck
>
> Another Dave
>
All advice noted!

--
“It is hard to imagine a more stupid decision or more dangerous way of
making decisions than by putting those decisions in the hands of people
who pay no price for being wrong.”

Thomas Sowell

On 10/27/23 12:32 AM, The Natural Philosopher wrote:
> On 27/10/2023 04:44, 56d.1152 wrote:
>
>>
>>    Solder IS the best.
>>
> No, actually it often isn't...
>
> The problem with solder on *stranded* wire is that it wicks up the wire
> and reduces it's flexibility by binding the strands together: That
> creates a stress concentration where it stops and a likely cause of
> fracture failure under vibration. That is why crimps are the choice for
> cheaper connections in high stress environments (e.g. automotive) or if
> you must solder you absolutely need to mechanically support the wire
> upstream of the solder joint.

I've had very bad luck with 'crimps' - esp when they are
exposed to the weather, but even in higher-vibration
environments. Wasted lots of time trying to track down
problems related to crimps. The worst case was a relative
who was into boats ... the connections WOULD show voltage
or a ground with today's high-impedence meters. Ultimately
had to build a LOW-impedence meter, with a big resistor
inside, that pulled a LOAD of about two amps. THEN you
could find the faults.

Solder correctly and put heat-shrink over it. You'll
be fine.

>>    But, remember "wire wrap" ?
>
> I was trained, as an apprentice, on military spec hardware construction:
> Wire wrap was one system that was used extensively in early digital
> hardware backplane prototyping.

Yep, it was VERY popular for prototypes back in
the day - and for good reason.

> Once the design was stabilised they tended to replace all that with a 2
> layer PCB.

I've also just seen plenty of cases where the successful
proto just got all its wraps soldered for posterity. Had
my hands on a whole LSI-11 kit computer done like that.

>>    Still have the tools
>>    for doing that. The more-extensive wrapping CAN
>>    be as reliable as soldered connections.
>
> Yes. especially in high vibration environments where components are not
> mechanically connected except by their leads or pins.

Vibration is the 'hidden threat' ... not always
an obvious issue to eye or mind, but it'll GET you.
Even pure copper wire will eventually develop
stress cracks due to vibration. I did a lot of
automotive/truck projects back in the day and we
learned to strap-down *everything* to keep it from
buzzing around.

Most 'computer' people these days are really most
entirely 'software'. They can't see mechanical
or noise or RF issues that crop up in the Real
World. The 'techs' who DO may not be as good
with software. It's a problem. There's a window
of maybe 1960 to 1985 where 'programming' and
'design/construction' kinda went together. Not
nearly as many now who cover one end to the other
except maybe the "BattleBots" crowd.

On Fri, 27 Oct 2023 21:57:07 -0400, 56d.1152 wrote:

> Most 'computer' people these days are really most entirely
> 'software'. They can't see mechanical or noise or RF issues that crop
> up in the Real World. The 'techs' who DO may not be as good with
> software. It's a problem. There's a window of maybe 1960 to 1985
> where 'programming' and 'design/construction' kinda went together.
> Not nearly as many now who cover one end to the other except maybe
> the "BattleBots" crowd.
>
No argument here (my background is systems design and programing on
Mainframes, minicomputers and fault-tolerant systems.

The other gang that understand interactions between electronics and
vibration are model flyers: radio control models, drones and, the most
vibration of all, IC powered free flight competition models: a current F1C
class model has a 2.5cc engine putting out around 1.3 HP at 30,000 rpm and
carrying electronic flight timers and a GPS-based radio beacon as a
retrieval aid. Free flight models regularly travel 2km or so in the course
of a 3 minute flight, especially if the contest is being run on
Sculthorpe, an ex-RAF/USAF base in Norfolk,UK. This area is known for its
fresh sea breezes.

--

Martin | martin at
Gregorie | gregorie dot org

In message <BuudnQ1ot_sf96H4nZ2dnZfqn_GdnZ2d@earthlink.com>
"56d.1152" <56d.1152@ztq9.net> wrote:

> On 10/27/23 12:32 AM, The Natural Philosopher wrote:
> > On 27/10/2023 04:44, 56d.1152 wrote:
> >
> > >
> > >    Solder IS the best.
> > >
> > No, actually it often isn't...
> >
> > The problem with solder on *stranded* wire is that it wicks up the wire
> > and reduces it's flexibility by binding the strands together: That
> > creates a stress concentration where it stops and a likely cause of
> > fracture failure under vibration. That is why crimps are the choice for
> > cheaper connections in high stress environments (e.g. automotive) or if
> > you must solder you absolutely need to mechanically support the wire
> > upstream of the solder joint.
>
> I've had very bad luck with 'crimps' - esp when they are
> exposed to the weather, but even in higher-vibration
> environments. Wasted lots of time trying to track down
> problems related to crimps.

I still remember a very interesting one in the 1980s with a joystick
for a Sinclair Spectrum. The box proudly proclaimed the use of gold
plating in the internal connections. They used fully (i.e. not
selectively) gold plated crimps onto stranded tinned copper wire.
One of the joints, although completely mechanically sound, was not
conducting electricity. Yes, that really was the interface between
the crimp and the wire.

I ran solder in and it was fine.

There is a known, but unfortunately not widely known, problem in the
interface between gold and tin.

The lesson boils down to:

1) Never mix gold plated and tin plated connectors.

2) If you're using gold plated connectors, use selectively gold plated
crimps in them.

David

On 10/28/23 6:42 AM, Martin Gregorie wrote:
> On Fri, 27 Oct 2023 21:57:07 -0400, 56d.1152 wrote:
>
>> Most 'computer' people these days are really most entirely
>> 'software'. They can't see mechanical or noise or RF issues that crop
>> up in the Real World. The 'techs' who DO may not be as good with
>> software. It's a problem. There's a window of maybe 1960 to 1985
>> where 'programming' and 'design/construction' kinda went together.
>> Not nearly as many now who cover one end to the other except maybe
>> the "BattleBots" crowd.
>>
> No argument here (my background is systems design and programing on
> Mainframes, minicomputers and fault-tolerant systems.

I did a lot of microcontroller-based projects back in
the day. This was "end to end" design. You had to not
only program, but implement the hardware - with
attention to all the real-world annoyances, and there
might be software tweaks required to HELP with those
Real World issues. Actual electronics/soldering was
involved.

Since that time, software/hardware have kind of become
distinct specialties ... but that middle ... where it
all has to come together ... seems to have been lost.

> The other gang that understand interactions between electronics and
> vibration are model flyers: radio control models, drones and, the most
> vibration of all, IC powered free flight competition models: a current F1C
> class model has a 2.5cc engine putting out around 1.3 HP at 30,000 rpm and
> carrying electronic flight timers and a GPS-based radio beacon as a
> retrieval aid. Free flight models regularly travel 2km or so in the course
> of a 3 minute flight, especially if the contest is being run on
> Sculthorpe, an ex-RAF/USAF base in Norfolk,UK. This area is known for its
> fresh sea breezes.

An actual hydrocarbon-fuel engine WILL create a lot
of very buzzy vibration - which WILL take its toll
on every connection. It's amazing how quickly some
connections will fail - chips can even work their
way out of conventional sockets.

And then, if an ignition system is involved,
transient electrical noise ! :-)

(which is usually high-voltage/micro-amperage, which
makes opto's esp useful)