zach's mac is back!

i <3 apple. they replaced my motherboard (for free), no questions asked (well, okay... they did ask questions when i brought it in... but nothing too tough.)

so yeah, i'm back in business. although i am NOT going to be plugging any more RepRap circuits into the machine. i'm just too afraid of my own incompetence. although i cant wait until v2.0 when the comms board is USB based. i'll plug that baby in =)

~Zach

RepRap Forum Mailer wrote:

> i <3 apple. they replaced my motherboard (for free), no questions asked (well, okay... they did ask questions when i brought it in... but nothing too tough.)
>
> so yeah, i'm back in business. although i am NOT going to be plugging any more RepRap circuits into the machine. i'm just too afraid of my own incompetence. although i cant wait until v2.0 when the comms board is USB based. i'll plug that baby in =)

Brilliant! In some ways we want to get to the position where Apple ask
as a matter of course, "Oh. You haven't plugged one of those bloody
RepRap machines in the wrong way round, have you? We have a special
warranty clause about that..."

Meters don't (usually) lie. If you power something up when it's not
plugged in, then measure the voltages on the pins before attaching a
valuable Mac, things ought to be all right.

--

Best wishes

Adrian

Dr Adrian Bowyer
[staff.bath.ac.uk]
[reprap.org]
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indeed. it is now a matter of practice for me to power up the board BEFORE plugging in the serial cord.

of course this whole mess will go away soon once i get my workspace setup properly and have all the boards permanently wired up. that will be nice.

A little while ago we had a bit of a discussion about polarized power
connectors as a result of Zach's unfortunate wire-swap incident.

If someone else already suggested this (or I did myself and have
forgotten...) apologies.

But the obvious connector to use is the 4-way Molex peripheral connector
that's on PC power supplies for discs etc - it can't go in the wrong
way, and most RR builders will use PC supplies which could then plug
straight in. We just leave out the two central pins...

--

Best wishes

Adrian

Dr Adrian Bowyer
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[reprap.org]
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heheh.... yup, someone did suggest it. that would be me... but it never really went anywhere on the mailing list. now that the benevolent dictator has decreed it, i'll add it to the board =)

a nice benefit of using these is that since you're hacking a pc power supply to use it anyway, you can just plug it directly in! if you need more wire... just splice some extra length on.

i'm also going to be using the molex stuff for the stepper motors. 4 wires /each designed for power? sign me up =) you can just take the extra connectors from your hacked pc supply, splice them onto your connectors, and you're ready to rock!

Quoting RepRap Forum Mailer :

> heheh.... yup, someone did suggest it. that would be me... but it
> never really went anywhere on the mailing list. now that the
> benevolent dictator has decreed it, i'll add it to the board =)

Sorry Zach - at least I apologised in advance...

> a nice benefit of using these is that since you're hacking a pc power
> supply to use it anyway, you can just plug it directly in! if you
> need more wire... just splice some extra length on.

Yup.

> i'm also going to be using the molex stuff for the stepper motors. 4
> wires /each designed for power? sign me up =) you can just take the
> extra connectors from your hacked pc supply, splice them onto your
> connectors, and you're ready to rock!

Yes - we need to use the fat ones with the two chamfered edges for the
main power, and the weedy ones (for floppies - remember them?) for the
steppers.

Best wishes

Adrian

Dr Adrian Bowyer
[staff.bath.ac.uk]
[reprap.org]
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i think we should use the big ones for everything... heres my reasoning:

any new power supply you buy will have 5-10 of the large molex connectors, and 0-1 of the floppy connectors. that means you can take your power supply, plug it into the board, leaving you with 4+ free connectors. you can cut those off of the power supply, splice them onto your motor / extruder and have cables ready to rock. no extra connectors to buy / make.

i like to think of it as using all the parts of a buffalo... errr... power supply.

(looks at his power supply connectors and sees that they're all female)

Um... Zach? Am I missing something in your idea here?

Quoting RepRap Forum Mailer :

> i think we should use the big ones for everything... heres my reasoning:
>
> any new power supply you buy will have 5-10 of the large molex
> connectors, and 0-1 of the floppy connectors. that means you can
> take your power supply, plug it into the board, leaving you with 4+
> free connectors. you can cut those off of the power supply, splice
> them onto your motor / extruder and have cables ready to rock. no
> extra connectors to buy / make.
>
> i like to think of it as using all the parts of a buffalo... errr...
> power supply.

I like your reasoning (and diet...). The only thing against is that
they are a bit chunky and take up a lot of land area.

Best wishes

Adrian

Dr Adrian Bowyer
[staff.bath.ac.uk]
[reprap.org]
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Adrian Bowyer wrote:

> I like your reasoning (and diet...). The only thing against is that
> they are a bit chunky and take up a lot of land area.

On further reflection, I don't think using these for the steppers is a
good idea. Reasons:

1. The connector is not just for steppers; it's for the extruder and
fan, both low current.

2. It's way over-engineered, and out of proportion to the rest of the
design.

3. You'd have to buy a special plug that different from all other
connectors on the board, even though the socket is 'free'.

It's Item 3 that is most important, I think. Let's stick with our
standard 2.54mm pin connectors (which are easily up to handling the
stepper current).


--

Best wishes

Adrian

Dr Adrian Bowyer
[staff.bath.ac.uk]
[reprap.org]
_______________________________________________
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I'm still a big fan of the connectors I'm using. They can't be connected
backwards and they're simple, small, decent current, pcb mountable,
reprappable and moderately cheap to buy.

Adrian Bowyer wrote:
> On further reflection, I don't think using these for the steppers is a
> good idea. Reasons:
>
> 1. The connector is not just for steppers; it's for the extruder and
> fan, both low current.
>
> 2. It's way over-engineered, and out of proportion to the rest of the
> design.
>
> 3. You'd have to buy a special plug that different from all other
> connectors on the board, even though the socket is 'free'.
>
> It's Item 3 that is most important, I think. Let's stick with our
> standard 2.54mm pin connectors (which are easily up to handling the
> stepper current).
>
>
>

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Simon McAuliffe wrote:
> I'm still a big fan of the connectors I'm using. They can't be connected
> backwards and they're simple, small, decent current, pcb mountable,
> reprappable and moderately cheap to buy.

Sorry Simon - I'm sure you've said in the past, but can you point us at
a URL with a pic?

--

Best wishes

Adrian

Dr Adrian Bowyer
[staff.bath.ac.uk]
[reprap.org]
_______________________________________________
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[reprap.org]

Adrian Bowyer wrote:
> Simon McAuliffe wrote:
>> I'm still a big fan of the connectors I'm using. They can't be
>> connected backwards and they're simple, small, decent current, pcb
>> mountable, reprappable and moderately cheap to buy.
>
> Sorry Simon - I'm sure you've said in the past, but can you point us
> at a URL with a pic?
>

Hopefully this comes through the mail server and forums...

Oh, here's the description I posted:

----
It comes in three parts. The first is a block that is mounted on the
circuit board containing some moderately heavy duty pins (see top two
sub-pictures). There is a rising key on the back that is close enough
to the pins to prevent the plug from being put on backwards. There is
also a lump part way down on this that acts as a locking mechanism to
hold everything together. The pins are square to increase the contact
area between them and the lugs.

The crimp-on lugs are just pressed with a die out of thin metal. You
break them off and solder/crimp them to the wire. They feature a small
sticky-outy-bit that locks the lug into the plug. They snap into the
holes on the side of the plug body.

The plug body has keys on it that match the width of the rising key on
the board mounted block. This prevents you from plugging it off to one
side. There is also a ridge at the bottom that locks onto the lump on
the block's rising key.

They seem to come with pin counts 2, 3, 4, 6 and 8

Very simple, but very user-proof.
----

They are deceptively simple really. There's a few subtle bits in their
design.

Locally (in NZ and Australia), they can be purchased from Jaycar
electronics. I assume it's a common part elsewhere too though, because
I've seen them in other equipment too.

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Simon McAuliffe wrote:
> Oh, here's the description I posted:

Oh, and a pic of them in situ in a few different situations. Some of
them are wired and some left unconnected, and the same plugs are used to
connect daughter boards for slave motors drivers.

The board incidentally is an old version 754410 based driver, but it's
still working nicely...

yes. you need a matching connector on the motherboard such as this:

[www.mouser.com]

it costs $0.88 for a grand total of $5.28 for all 6 boards. considering our project is running around $400 total, thats about 1% of the cost.