.1" pin Pitch question

Hi All.

Bit of an odd one for you. I develop most of my work using A Mega 1280 or 2560, initially on breadboard and then on to strip board.

All he analogue and power pins are on 0.1" (2.54mm) Pitch. Why are the Digital Pins (between 7 and 8) on a 0.05" Pitch.

There has to be a reason. This simple thing makes it really hard work to use Strip Board.

Ideas and comments welcome.

I've heard it was actually a design mistake.

But I can also imagine that it was done on purpose so people will not mount a shield the wrong way around.

https://forum.arduino.cc/index.php?topic=23012.0

Search for "Arduino prototype board" on ebay.

Bare strip boards that fit an Uno (or Mega) are about $2 each when bought in a 10-pack. Leo..

sterretje: I've heard it was actually a design mistake.

But I can also imagine that it was done on purpose so people will not mount a shield the wrong way around.

No it was actually a mistake on the first mass production PCB, and they kept in on so shields designed for that would work on later shields. I got the full story from the person who made that mistake a few years ago at a Rome Maker Faire.

Here's the explanation from Massimo Banzi: http://forum.arduino.cc/index.php?topic=22737.msg171839#msg171839

I made that mistake, when I made the first arduino board.

David Cuartielles took my first rectangular design , fixed a mistake (his first contribution) by applying the flying resistor you see. and turned it into this when I put some finishing touches I managed to get the spacing wrong...

We had 5 minutes before the deadline to go into production, the PCB guy was on the phone saying "send it now or it goes to next week" and we didn't have a name yet... they I said let's call it Arduino like a bar we used to go...there wasn't much time to think.

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 :)

Massimo

Thank you all for your replies. I'm glad it's not only me that finds this 'mistake' a real pain.....

Yeah, I’m not fond of the mistake like Massimo Banzi is. It makes those Arduino boards more proprietary since you can’t easily create your own shields with stripboard or protoboard. To me, having a non-standard pin spacing goes against what the hardware hacking movement stands for. I try to avoid using those boards. Some crooked traces to give character without impacting functionality would be fine, but not this. Luckily we have other nice boards without the weird spacing like the Nano, Pro Mini, Pro Micro. Arduino’s newest boards are all in the “MKR” form factor, which has standard spacing and is breadboard friendly so I think they’ve come to their senses. Hopefully the 3rd party shield manufacturers will take up that standard instead of requiring the use of the MKR2UNO adapter.

ParCan: I develop most of my work using A Mega 1280 or 2560, initially on breadboard and then on to strip board. ... This simple thing makes it really hard work to use Strip Board.

There are good quality proto boards available for Mega, so where's the problem? All you are doing is making life hard for yourself, and it sounds like you have been doing that for quite a while.

I’ve never come across a stripboard protoshield. Most of them are pretty annoying because they have a bunch of random footprints that might happen to be useful to someone. I did find a simple protoboard style shield for the Mega after some searching but I much prefer stripboard unless I’m trying to do a really compact design. And by stripboard I mean the real stripboard, not the tripad style.

Yep, the bottom one is the Mega shield I was talking about. Definitely the best I've found and they are pretty cheap on eBay. I'm not sure what the reasoning was behind the cutout part on the top one and I'm not sure whether I'd like the bus bars.

Still not stripboard though.