Mini-Shield form factor?

Hi,

Perhaps the following suggestion already exists?

Would it be beneficial to come up with a "mini-shield" form factor? I'm thinking of something that would piggyback on the pro-mini series(#0). Quite often the real estate needed for the components for a shield don't take up much space and could "easily"(#1) fit in a much smaller footprint. An adapter board could be made so that a mini-shield could be attached to a regular Arduino shield form factor.

I see a few possible benefits:

  1. Small is beautiful - folks came up with Arduino Pro-Mini for a reason. Same reasons apply for peripheral hardware as well
  2. Make it standard and make it modular so as to encourage shield makers to adopt it. Maybe any shield that can be made in that size would be the standard - and then using adapters for bigger boards. Although, I'm sure that'll create an outcry in the event it makes new users buy an adapter board. But maybe it would be a wash in the long run? Smaller boards are (slightly) cheaper to produce. You could have many "mini-shields" and only need one "mini-to-normal shield adapter".
  3. It encourages cross-pollination(#2). Some other hardware has adopted the shield pin out - that shows there's a desire to tap into the Arduino Shield market. However, for some projects it appears overkill to have a (relatively) "honking big shield" when only a few components are needed.

Notes:
(#0) - I realize that this might require a compromise on some pins? (not sure entirely). That's just my starting suggestion
(#1) - Easily is in quotes because I'm a software engineer and I just assume you hardware types can miniaturize anything! (That's a compliment!!!)
(#2) - Dear Arduino, Sorry and please don't feel bad, but I've started dating other hardware boards. I still love you though! Can we have an open relationship?

What do you think?

You say: A good idea? I reply: Cool, how do we get it done?
You say: A bad idea? I reply: OK, why? What problems need to be addressed?
You say: Been done before and the implementation chosen rocks? I reply: Would you kindly point me to that implementation? Thanks!
You say: Been done before but the implementation chosen sucks? I reply: OK, so why did it suck and can we learn lessons and do it mo' betterer this time?

Take a look at www.gravitech.us
They have a whole line of shields for Nano's.
Maybe adapt them to use with Promini?

At the same time, a promini is not much more than a surface mount breakout board.
I'd just as soon put the chip on a custom board with other needed components, get a set of PCBs from iteadstudio (or whomever) for $10 and then not have to deal with all the headers & stuff.

CrossRoads:
Take a look at www.gravitech.us
They have a whole line of shields for Nano's.
Maybe adapt them to use with Promini?

Sweet - this is indeed what I was looking for. Now I have to persuade 'em to make a CAN shield.

At the same time, a promini is not much more than a surface mount breakout board.
I'd just as soon put the chip on a custom board with other needed components, get a set of PCBs from iteadstudio (or whomever) for $10 and then not have to deal with all the headers & stuff.

Ahh yes, but you're a better man than me - I can't solder to save my life (and I've botched a number of expensive components trying =( ). I note that you've got 25 years experience in hardware - I have about the same in software. My business partner tends to run screaming from the room if I pick up a soldering iron...

Plug and Play was made for folks like me - which is why the gravitech link is so good. Thanks.

One day, I'll get someone to teach me how to solder properly - I definitely want to learn. Just always running out of time...

Thanks again!

Glad to help.
Sparkfun carries a normal size CANBUS shield based on MCP2515 with MCP2551 transceiver.
If gravitech carries a nano to uno type adapter, maybe you could use that.

Maybe this and a few wires?

This idea is something I've thought about for a while. Mainly because seeedstudio's $10 PCBs are 1.9" square and the arduino shield needs to be 2.1" to span both rows of headers. That extra 0.2" raises the price from $10 to $25. I considered an adapter that I'd only have to make once for unlimited mini-shields but it will be annoying to have the extra layer just to use non-standard shields.

The other thing I've thought of is making an oversized adapter shield that will have spots for 4 mini-shields, replicating all or some of the IO multiple times, so as long as you're careful of which pins you use on each mini-shield, it should make modular design easier. That still misses the whole point of wanting to do quick cheap easy shields though.

So something like this? 71x43mm Get charged for 50x100mm cards. $22 I think?

Oracle:
This idea is something I've thought about for a while. Mainly because seeedstudio's $10 PCBs are 1.9" square and the arduino shield needs to be 2.1" to span both rows of headers.

Don't quote me, but I'm pretty sure I've seen shields done on the 5 cm square boards. The header pin holes are awfully close to the edges, but they appear to fit.

danb35:
Don't quote me, but I'm pretty sure I've seen shields done on the 5 cm square boards. The header pin holes are awfully close to the edges, but they appear to fit.

I believe that might be possible if you basically solder the headers along the outer edges of the board, maybe have drill holes that are broken open by the edge of the board as guides. I couldn't find anything about it though. If you have any links, I'd love to see how it came out.

Oracle:
If you have any links, I'd love to see how it came out.

Found it:
http://seeedstudio.com/forum/viewtopic.php?f=9&t=2416&sid=da67ed081438154a131067df942a4e59

maybe have drill holes that are broken open by the edge of the board as guides.

You could probably use "castellated vias" (vias that are cut in half by the routing process) and solder the headers along the edge of the PCB.


Rob

danb35:
Found it:
http://seeedstudio.com/forum/viewtopic.php?f=9&t=2416&sid=da67ed081438154a131067df942a4e59

Interesting. I've been playing with eagle and carefully measuring my Diecimila and some shields I had made using the 10x10 service. It looks like the headers are 1.9" apart and 50mm is 1.968 inches, so I should have 0.8mm minus 1/2 the drill size on the outside of my header (mixing metric and imperial is not fun). The standard square posts in headers are 25mil, or 0.635mm, so I don't think I should use a drill size smaller than 0.8mm.

That actually does let me have some board material left around the hole, thought it's cutting it awfully close and in your image it looks like he as a lot more than my estimate.

It's definitely worth giving it a try next time I need a shield, because as I said even if I end up with my holes split, the board will still work.

There is also this sort of hack, assuming your shield doesn't need ALL of the pins. Note that +5, GND, RESET, and digital pins 11, 12, and 13 also appear on the ISP connector, and you can adjust the tilt to include the analog pins if you'd rather...

One day, I'll get someone to teach me how to solder properly - I definitely want to learn. Just always running out of time...

On youtube there are some solder courses, they might help ... but the real way is start doing it (and learn from your mistakes)

One point, use a decent iron. They might costs a few $$ more but you will enjoy them longer (I hope :wink: