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Topic: Why is IOH connector off grid ? (Read 882 times) previous topic - next topic

romanz

Jul 07, 2014, 03:07 am Last Edit: Jul 07, 2014, 03:58 am by romanz Reason: 1
Quick one-off project where custom PCB is out of budget and timeframe. I always have few UNOs and universal 0.1" grid PCBs in the drawer. POWER, AD and IOL, even ICSP headers are in grid but IOH is off grid. I usually cutout space for IOH and use remaining pins only.

Just curious, why Arduino designers moved IOH off grid? It cripples platform for use with limited I/O or shields designed for Arduino only.

LarryD

I thought it was done that way to make it difficult to plug things in backwards.
Or maybe to make it difficult to make shields for their platform.
Or maybe it was a mistake.

Who knows?
The way you have it in your schematic isn't the same as how you have it wired up!

Coding Badly


http://www.lmgtfy.com/?q=arduino+why+are+shield+pins+offset

Grumpy_Mike

It was a mistake on a very early prototype that is now kept for backwards compatibility.

romanz

Thanks everyone for taking time to educate me. I am late to this scene, so I missed early discussions in 2008, sorry for bringing old beaten topic back to life, I did search before posting, but used wrong keywords.

The idea with bent headers is neat, I tried it and built shield from 5x7cm proto pcb, now I need to find something useful to install on it :)

romanz

Why would this topic be moved to junk forum, it's an older topic, but still a topic. I see folks beating trivial topics or topics that have been resolved decades ago over and over. Should people invest time in a forum where moderators send legitimate topic to a junk pile because it's something they screwed up time ago and don't want to hear questions about it ?

Coding Badly


Where would like this thread to reside?

liudr

Could be general electronics or other hardware development. It doesn't seem to belong to the bar sub-forum.

Misaligned pins had some effect on me. I learned how to use EAGLE and designed my first board (guess what?a shield) since I wasn't sure how to make a shield out of perf or standard PCB. Yeah, the misalignment sucks. I guess with the wide spread of arduinos, people will soon mystify this like Roman horse ass and American railroad gauge.

romanz

#8
Jul 08, 2014, 04:19 am Last Edit: Jul 08, 2014, 04:22 am by romanz Reason: 1
I posted it in general electronics, why did you move it ? Don't take it wrong, I appreciate the lmgtfy link

Here is basic shield for $0.30. Sometimes you only need to read PIR, sound buzzer and  blink LED, so 12 I/Os are plenty.

liudr

LOL, good idea to just get around those pins if you don't need them. Why didn't I think about skipping those pins? Many of my early projects using thru-hole parts, like doing two photo gates etc only needed a few pins. A 1/8" stereo socket fits on a perf board just fine, so is a thru-hole power barrel with pins. 0.1" and 0.2" spacing screw terminal blocks fit too. I've even fit coin battery holders and buzzers on them, although I had to use different rows of pins.

But to be honest, there is no way I'm going back making perf board projects. My right hand is glued to my mouse now. Sometimes I just make a design and get it printed and THEN prototype it on the PCB. Printing gets so cheap that if I make mistakes, I keep the coasters in a pile as practice material for my students.

Grumpy_Mike

Why cut out the corner of the board, why not just not fit the header pins in that place?

romanz

#11
Jul 08, 2014, 04:36 pm Last Edit: Jul 08, 2014, 04:38 pm by romanz Reason: 1
If you are not stacking, or don't need anything on IOH for top shield, you do not need to cut out anything

liudr

That UNO looks just like mine, maybe R2 or R1, not R3, right? I have one R2. It has problems with running SD card 50/50 time card won't start.

romanz


That UNO looks just like mine, maybe R2 or R1, not R3, right? I have one R2. It has problems with running SD card 50/50 time card won't start.


Got it from Mouser several years ago, it is definitely not R3, last pin is AREF. This is only original I have, are we allowed to post here pictures of a knock-offs ?

liudr

I am leaning towards using compatible boards that don't say arduino or use the infinity+- symbols. If I happen to have got one that says that, I call it knock-off. If it has no arduino printed on it, I call it compatible board. Yeah, no one is policing this.

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