Arduino Forum

Development => Suggestions for the Arduino Project => Topic started by: ardnut on Aug 06, 2012, 06:11 am

Title: pin 7,8 irregular offset
Post by: ardnut on Aug 06, 2012, 06:11 am
Hi,

what is the point of the irregular spacing between pins 7 and 8 on Arduino?

This makes its very inconvenient when wanting to add a prototype shield since the two connectors on this side of the board cannot be made to line up with a standard piece of matrix board.

What was the point of this "feature" and what was the intended way to interface to the board without making a customised PCB?

thanks
Title: Re: pin 7,8 irregular offset
Post by: dxw00d on Aug 06, 2012, 09:03 am
This was argued about only a couple of weeks ago. Short story - it was an error in the original design that wasn't spotted in time. It does prevent shields from being attached the wrong way round though. There are a number of places to obtain offset headers that conform to normal spacing.
Title: Re: pin 7,8 irregular offset
Post by: CrossRoads on Aug 06, 2012, 04:53 pm
Offset header
https://www.sparkfun.com/products/9374

doesn't help get those last 2 pins on the later boards tho.
Title: Re: pin 7,8 irregular offset
Post by: ardnut on Aug 07, 2012, 12:21 pm
OK thanks, it looked like an error. I suppose it can now be called a polarisation feature. Though the extra pins on the newer boards make it fairly obvious which way around things go.

I'll have to bend some std header pins to get around it,  I just couldn't understand why it was there.

Thanks for the explanation.
Title: Re: pin 7,8 irregular offset
Post by: westfw on Aug 08, 2012, 10:45 am
It *was* an error.  But now it's become a standard, instead :-)
You'd be surprised how many standards are born that way!
Title: Re: pin 7,8 irregular offset
Post by: bperrybap on Aug 08, 2012, 08:54 pm
As an alternative, if you want to use standard proto/strip boards, with standard header pins/sockets,
you can buy third party boards that have an additional set of holes.
This gives you both the "Arduino" offsets as well as standard offsets if you solder
in another header.
The Seeeduino is an example of such a board:
http://www.seeedstudio.com/depot/seeeduino-v221-atmega-328p-p-669.html (http://www.seeedstudio.com/depot/seeeduino-v221-atmega-328p-p-669.html)

The Arduino team rejected this idea as they claimed it ruined the beauty of the board
and that the board with its flaw represents the natural flaws in all things.

--- bill
Title: Re: pin 7,8 irregular offset
Post by: Far-seeker on Aug 08, 2012, 09:51 pm
Shouldn't they have an explanation in the FAQ (http://arduino.cc/en/Main/FAQ) by now? :P
Title: Re: pin 7,8 irregular offset
Post by: PaulS on Aug 09, 2012, 01:06 pm
Quote
Shouldn't they have an explanation in the FAQ by now?

Why? No one reads that anyway.
Title: Re: pin 7,8 irregular offset
Post by: pico on Aug 10, 2012, 01:21 pm

The Arduino team rejected this idea as they claimed it ruined the beauty of the board
and that the board with its flaw represents the natural flaws in all things.


LOL. Like the natural flaw in this line of reasoning.

Actually, it seems to be a philosophy which permeates their attempts at software engineering as well. Seriously, if there is any substance to this, it could explain quite a lot!
Title: Re: pin 7,8 irregular offset
Post by: Far-seeker on Aug 10, 2012, 04:12 pm

Quote
Shouldn't they have an explanation in the FAQ by now?

Why? No one reads that anyway.


Well even so we could link to it everytime someone posts a question about it...
Title: Re: pin 7,8 irregular offset
Post by: bperrybap on Aug 10, 2012, 06:10 pm


The Arduino team rejected this idea as they claimed it ruined the beauty of the board
and that the board with its flaw represents the natural flaws in all things.


LOL. Like the natural flaw in this line of reasoning.

Actually, it seems to be a philosophy which permeates their attempts at software engineering as well. Seriously, if there is any substance to this, it could explain quite a lot!


I think it is somewhat of a philosophy or at least a high level of tolerance/acceptance for such things.

One of several comments from Massimo on the subject:

Quote
Then I'm fond of the mistake... it makes it not perfect therefore more human... Yes...it could have been all perfectly optimised... but if engineers ran the world it would be an unbearable place where to live


http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1212632541 (http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1212632541)

--- bill