Arduino – fix your pin spacing!

From the Arduino Diecimila page on

Physical Characteristics

… Note that the distance between digital pins 7 and 8 is 160 mil (0.16″), not an even multiple of the 100 mil spacing of the other pins.

Seriously, why???  This means you can’t drop a protoboard on top of an Arduino without a lot of pain dealing with digital pins 8-13.

Of course now it’s too late to switch because everyone that has designed shields for the Arduno made them to fit the weird offset between pins 7 and 8.


13 thoughts on “Arduino – fix your pin spacing!”

  1. This shield serves as programmer for ATmega48/88/168 Arduino, ATtiny2313, ATtiny13, ATmega32?
    One could add ATtiny13, ATmega32?

  2. I heard that with the odd pin spacing, it’s impossible to plug in a shield backwards. Not sure if that was a “bug turned feature”, or if it was designed that way on purpose. I sincerely hope it’s not to discourage the use of home-brew protoboard shields, as that would be very disappointing.

    1. Don’t quote me on this, but I think I heard Tom Igoe say that this was an honest mistake that was carried into the first production boards, and after shields started being developed there was no way to fix it without breaking backwards compatibility. I may be misremembering, but that certainly sounds like a plausible explanation to me!

      You’re right about not being able to plug a shield in backwards, I never thought of it that way before… Well, maybe if you push hard enough. 🙂

  3. I’m currently trying to get around this. I think I’m just going to order a Seeeduino, which does this right and has 2 extra pins to boot. Either that or just bend the pins a bit to make it fit into a normal Arduino. This looks like an egregious oversight they should have fixed years ago before people started making shields. They could still fix it, and just make some kind of adapter for people using old shields on new boards. But for a board that’s supposed to be easy for hobbyists, this one little difference of 40 mils is a huge barrier.

  4. I am fairly new to the Arduino world, so take that in account when assessing if I am just full of it 😉
    I find that when people do things like this, we tend to think of it as a mistake. Could it have the *intention* to not allow us to easily piggy back here? Maybe it would take some ingenious and motivated individual to provide some creative workaround for this, or even come up with a functionally equivalent (and popular) knock off?

  5. At this point I think they are stuck now that so many people have created shields for the original pinout.

    I hadn’t seen the iDuino before, it looks like a good alternative to the Boarduino.

  6. Can’t figure out why they perpetuated the 160mm spacing to the Duemilanove– grr! iDuino all the way for me.

  7. I agree totally. It makes making protoboard shields very difficult. I realised this when trying to make a lcd screen shield. I gave up 3/4 of the way through. fortunately i found your high voltage programmer and used my premade proto-shield and made the high voltage programmer in one day! Yeah, now that “useless” chip is saved.

    But seriously, they should have thought about that…..

    I will hopefully be able to make a robotics geared arduino platform for robots in the future.. I would like it to have multiple spaced shield compatible… compatible with “normal” shields, and even spaced protoboard ones. Maybe even support for those smaller bluetooth shields too…

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