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[on:]

So I have quite a few shields sitting around right now, and I would like to use at least 4 of them in my latest project, however I know that the shields make use of the same pins. Is it possible to get these shields running by interfacing them to a bread board or am I physically limited by the amount of pins connected to the Uno?

[Reply #1 on:]

Generally not an issue but it depends on if the conflicting pin(s) can be remapped or if the pin is a specific purpose pin.

Is this four of the same shield?

Do you have details on the shield(s) you want to use?  That would help determine the feasibility.

[Reply #2 on:]

Not long ago there were some very long discussions surrounding shields and their pins and I think someone ended up creating a website to detail the pin usage of each known shield. Does anyone recall the website address?

What shields are you using and who manufactured them? Very high chance exists that they won't work together.

[Reply #3 on:]

I think you mean http://shieldlist.org

You can use a "breakout shield" like our Quick Shield or Aussie Shield to keep the shield off the Arduino but still run wires to various pins, and possibly reassign pins that are in conflict.

Still, it does depend on exactly what shields you are planning on using.

--
The Aussie Shield: breakout all 28 pins to quick-connect terminals

[Reply #4 on:]

Well the shields that I can see that conflict are the
WiShield 2.0: http://shieldlist.org/asynclabs/wishield-v2
WeatherShield1: http://shieldlist.org/ethermania/weathershield1

They both use D7 and D2 pins, now I could probably reroute the pins and change the software for interacting with them, but this is just the first problem, I also want to add a XBee shield and a motor shield (as well as many other sensors), so can I somehow extend the number of pins I can use on the Arduino?

[Reply #5 on:]

You know with that many shields you might be better off dedicating one Arduino per shield and having them communicate via I2C or (soft)serial. That will probably get you going faster than trying to stuff all the software on one Arduino and figuring out the pins.

--
The Rugged Motor Driver: two H-bridges, more power than an L298, fully protected

[Reply #6 on:]

@Narwhal


The WeatherShield1 uses the D7 (clock) and D2 (bi-directional data) pins to communicate with Arduino in a synchronous serial protocol similar to what is implemented in the "old" MM5450 LED driver. Moreover one could hack the shield un-soldering one side of the two resistors connected to these pins and connect them to the new pins.
The libraries that control the communications between the shield and Arduino could be informed about this hardware change specifying the new pins in the constructor when building the main WeatherShield1 object hander (see the examples in the weathershield1_comm sketch).

Thank you.

[Reply #7 on:]

Just a generic suggestion:
You can snip off the male pin on a shield, jump the top (female header) to a different pin. Say you need to move digital pin 2 to another pin say digital 6. The PCB has hardwired pin 2 to something but pin 6 is not used. You go ahead and clip off pin 2's male "tip" that is facing down, then use a jumper to jump pin 2 to pin 6, if the headers are female stacking headers with long pins.

[Reply #8 on:]

Right! That's a good idea.
Thank you!