OMC-to-2560 adapter

[John Brown]

Hi,

I have been wondering about how you intend to couple the boards.

I propose the use of "Arduino Stackable Headers" they are readily
available in various strip lengths and various leg

lengths (as headers or sockets).

The header shown in the photo gives a clearance of about12mm above the
socket which I think might just be enough, if not then a header/socket pair.

I don't think wire wraps will be suitable as they usually have quite
robust 'square pins' which will not fit well in the sockets we have.

Regards

John Brown.




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[Alex Gibson]

Hi Malcolm, John, Bob, anyone else following this?

I'm looking at stacking options now, got some good options including the below.

I've realised that the height of the tallest component on the board might be a bit more variable than I originally expected...

When soldering up my own OMC I naturally seated the TSOP components (transistors) as low as they could go, per standard practice. However I encountered at least one board where the legs were left full length, but soldered so the tips were at a 'normal' 1-2mm through the board, and so stuck out much higher from my own.

I wonder if you guys could confirm how tall from the board your tallest component is?

Since I could fix the one I have that’s super tall, I would just like to see if there's a real variability among your boards that I need to account for!

Cheers,

Alex Gibson

+44 7813 810 765 @alexgibson3d 37 Royal Avenue, Reading RG31 4UR

admg consulting

edumaker limited

• Project management
• Operations & Process improvement
• 3D Printing

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[Malcolm Napier]

Hi everyone,

I probably have the largest sample of OMCs (7 at the last count, including 2 that are still components).

However, it might take me a couple of days to look at them closely, due to a large number of meetings (physically distanced and virtual) that have suddenly accumulated in my diary. 

Please bear with me. I will get onto them as soon as I can. 

Regards, 

Malcolm 

To view this discussion on the web, visit https://groups.google.com/d/msgid/tvreprapug/007001d6bc27%24e83ee230%24b8bca690%24%40alexgibson.net.

[Bob Dunlop]

On Mon, Nov 16 at 02:51, Alex Gibson wrote:
...

> I wonder if you guys could confirm how tall from the board your tallest component is?

My transistors stand at 22mm from the PCB surface. There's another issue
with the serial port which I mounted vertically but that a purely local
problem that I would have to fix.

Now remember you are building a stack of several components between the
boards. The 20mm standoff only contributes 17mm between the boards as it
is measured between pin ends and 3mm goes through the PCB for soldering.
However the turned pin socket plugged into the existing OMC socket gives
you 7-8mm for a combined inner face to inner face distance to 24-25mm.

Plenty of room.

--
Bob Dunlop

[Tony Hine]

>>>Hi Malcolm, John, Bob, anyone else following this?<<<

I am, but only as an observer....

[Alex Gibson]

Lurking is positively encouraged.  Long time no see Tony!

 

I have 10 bare boards in hand for 6 people, two of whom have multiple boards, and I will be ordering more PCBs for other reasons soon so there’s a strong likelihood of a round 1.5 of this…

 

Cheers,

 

Alex Gibson

 

+44 7813 810 765    @alexgibson3d    37 Royal Avenue, Reading RG31 4UR

 

admg consulting

 

edumaker limited

 

·         Project management

·         Operations & Process improvement

·         3D Printing

 

To view this discussion on the web, visit https://groups.google.com/d/msgid/tvreprapug/CA%2B%3DVDnzHTvM459eCn6beo22n9oPCDcKdaFscaLKkSVxsQc%3D6OA%40mail.gmail.com.

 

Virus-free. www.avg.com

 

[mikethebee]

I have been observing too, lurking would involve more intention. Anyway, I spoke to Alex today to confirm I am more interested now then when the project was first suggested. Partly because I hadn't really understood how many useful features it included and partly because I was confusing it as part of Bo's mechanical upgrade.

As he will have spare  boards I am going to follow things more actively.

-MikeTheBee

[Alex Gibson]

A quick update!

 

I have a small number (4 or 5) of bare ATMEGA2560 chips.  I have in stock the rest of the components to make up a board to test.

 

I am hoping this weekend to first practice using a similar footprint chip from an old piece of electronics, and then solder up one of the ATMEGA2560s to an OMC2560 board for real, then test I’ve managed to do this successfully.  I’ve done plenty of SMT rework on similar pitched chips, but it’s a lot of pins!    

 

To assist this… Do any of you know a good value/quality source for flux gel?  IE the kind of flux you can put gobs of around SMT components and doesn’t instantly boil off? 

 

I’m very much sold on the benefits of using the right kind of flux (check out this video… https://www.youtube.com/watch?v=NoxQsmzJ5tg) but not keen to pay a triple premium for something made in the US, plus shipping and customs duty.  Does anyone know of a good supplier in the UK/Europe?

 

Cheers,

 

Alex Gibson

 

+44 7813 810 765    @alexgibson3d    37 Royal Avenue, Reading RG31 4UR

 

admg consulting

 

edumaker limited

 

·         Project management

·         Operations & Process improvement

·         3D Printing

 

From: tvrep...@googlegroups.com [mailto:tvrep...@googlegroups.com] On Behalf Of mikethebee
Sent: 19 November 2020 12:52
To: TVRepRapUG
Subject: Re: [TVRepRapUG] OMC-to-2560 adapter

 

I have been observing too, lurking would involve more intention. Anyway, I spoke to Alex today to confirm I am more interested now then when the project was first suggested. Partly because I hadn't really understood how many useful features it included and partly because I was confusing it as part of Bo's mechanical upgrade.

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[Alex Gibson]

Hi all

 

A further few significant lurches forward of progress have occurred…

 

I finally have a few boards with the ATMEGA2560 chip successfully surface mount soldered to them.  

This was very tricky, it was actually done some time ago but I am only confident to call them done now that a) I have bought and received an inspection microscope to check the pins have been done properly, and b) I’ve successfully repaired a MakerBot Mightyboard which uses the same 100-pin QFP package and fully tested it – so I know I’ve got the techniques right.

 

Key learnings – 1) take storage of these components extremely seriously – a couple of wonky pins form poor packing when they were sent to me made for a tough time ensuring alignment  – and 2) have a decent microscope!

 

So I can FINALLY actually load firmware and test a board, will do so this week.

 

I have a fair quantity of most components so assuming the boards work as expected, I can get bare boards or the first kits out very soon!

 

Cheers,

 

Alex Gibson

 

+44 7813 810 765    @alexgibson3d    37 Royal Avenue, Reading RG31 4UR

 

admg consulting

 

edumaker limited

 

·         Project management

·         Operations & Process improvement

·         3D Printing

 

To view this discussion on the web, visit https://groups.google.com/d/msgid/tvreprapug/030601d6be81%24780cc610%2468265230%24%40alexgibson.net.

[Alex Gibson]

Sorry to double up the email but just in case the photo causes  issues… here is a photo of a board with soldered ATMEGA and a close up of successfully soldered pins.

 

I strongly recommend letting me solder it for you unless surface mount soldering is something you do for fun! 

 

The rest of the board is easy through-hole just like the original OMC…

 

 

 

Alex Gibson

 

+44 7813 810 765    @alexgibson3d    37 Royal Avenue, Reading RG31 4UR

 

admg consulting

 

edumaker limited

 

·         Project management

·         Operations & Process improvement

·         3D Printing

 

From: Alex Gibson [mailto:al...@alexgibson.net]
Sent: 16 February 2021 10:07
To: 'tvrep...@googlegroups.com'
Subject: RE: [TVRepRapUG] OMC-to-2560 adapter

 

Hi all

 

A further few significant lurches forward of progress have occurred…

 

I finally have a few boards with the ATMEGA2560 chip successfully surface mount soldered to them.  

This was very tricky, it was actually done some time ago but I am only confident to call them done now that a) I have bought and received an inspection microscope to check the pins have been done properly, and b) I’ve successfully repaired a MakerBot Mightyboard which uses the same 100-pin QFP package and fully tested it – so I know I’ve got the techniques right.

 

Key learnings – 1) take storage of these components extremely seriously – a couple of wonky pins form poor packing when they were sent to me made for a tough time ensuring alignment  – and 2) have a decent microscope!

 

So I can FINALLY actually load firmware and test a board, will do so this week.

 

I have a fair quantity of most components so assuming the boards work as expected, I can get bare boards or the first kits out very soon!

 

Cheers,

 

Alex Gibson

 

+44 7813 810 765    @alexgibson3d    37 Royal Avenue, Reading RG31 4UR

 

admg consulting

 

edumaker limited

 

·         Project management

·         Operations & Process improvement

·         3D Printing

 

From: tvrep...@googlegroups.com [mailto:tvrep...@googlegroups.com] On Behalf Of Alex Gibson

Sent: 19 November 2020 14:37
To: tvrep...@googlegroups.com
Subject: RE: [TVRepRapUG] OMC-to-2560 adapter

 

A quick update!

To view this discussion on the web, visit https://groups.google.com/d/msgid/tvreprapug/030601d6be81%24780cc610%2468265230%24%40alexgibson.net.

[Alex Gibson]

You wait months for one of these to be soldered up, and then 3 come along at once…

 

The workflow is now 100% there, with the better reflow soldering station, proper flux, solder wick and a USB microscope for inspection, I’m finally able to do these professionally.

 

Got 3 with the ATMEGA soldered, will now populate 1 board with the rest of the components and get some firmware loaded…

 

 

 

Alex Gibson

 

+44 7813 810 765    @alexgibson3d    37 Royal Avenue, Reading RG31 4UR

 

admg consulting

 

edumaker limited

 

·         Project management

·         Operations & Process improvement

·         3D Printing

 

From: Alex Gibson [mailto:al...@alexgibson.net]
Sent: 16 February 2021 10:16
To: 'tvrep...@googlegroups.com'
Subject: RE: [TVRepRapUG] OMC-to-2560 adapter

 

Sorry to double up the email but just in case the photo causes  issues… here is a photo of a board with soldered ATMEGA and a close up of successfully soldered pins.

 

I strongly recommend letting me solder it for you unless surface mount soldering is something you do for fun! 

 

The rest of the board is easy through-hole just like the original OMC…

 

 

 

Alex Gibson

 

+44 7813 810 765    @alexgibson3d    37 Royal Avenue, Reading RG31 4UR

 

admg consulting

 

edumaker limited

 

·         Project management

·         Operations & Process improvement

·         3D Printing

 

From: Alex Gibson [mailto:al...@alexgibson.net]

Sent: 16 February 2021 10:07
To: 'tvrep...@googlegroups.com'
Subject: RE: [TVRepRapUG] OMC-to-2560 adapter

 

Hi all

 

A further few significant lurches forward of progress have occurred…

 

I finally have a few boards with the ATMEGA2560 chip successfully surface mount soldered to them.  

This was very tricky, it was actually done some time ago but I am only confident to call them done now that a) I have bought and received an inspection microscope to check the pins have been done properly, and b) I’ve successfully repaired a MakerBot Mightyboard which uses the same 100-pin QFP package and fully tested it – so I know I’ve got the techniques right.

 

Key learnings – 1) take storage of these components extremely seriously – a couple of wonky pins form poor packing when they were sent to me made for a tough time ensuring alignment  – and 2) have a decent microscope!

 

So I can FINALLY actually load firmware and test a board, will do so this week.

 

I have a fair quantity of most components so assuming the boards work as expected, I can get bare boards or the first kits out very soon!

 

Cheers,

 

Alex Gibson

 

+44 7813 810 765    @alexgibson3d    37 Royal Avenue, Reading RG31 4UR

 

admg consulting

 

edumaker limited

 

·         Project management

·         Operations & Process improvement

·         3D Printing

 

From: tvrep...@googlegroups.com [mailto:tvrep...@googlegroups.com] On Behalf Of Alex Gibson

Sent: 19 November 2020 14:37
To: tvrep...@googlegroups.com
Subject: RE: [TVRepRapUG] OMC-to-2560 adapter

 

A quick update!

To view this discussion on the web, visit https://groups.google.com/d/msgid/tvreprapug/030601d6be81%24780cc610%2468265230%24%40alexgibson.net.

[Trevor Moseley]

Yup, I do it for fun, I'm very good at drag soldering those components, 100% success rate so far (only done around 20)

To view this discussion on the web, visit https://groups.google.com/d/msgid/tvreprapug/015b01d70498%2421cdbb30%2465693190%24%40alexgibson.net.