Arduino Yun and seeed motor shield compatibility question

Hi, I am planning on running some motors from the seeed motor shield with a yun, and I'm new to this so I'm wondering (1) if they're compatible at all (I mean they fit together if you have extra headers, but will it still work) and (2) If they are, I know that you shouldn't power a yun through the 5V pins along the side, but if I have a power source going into the shield would that power be sent through those pins and wreak my yun?

Thanks

Usually motor shields are designed to work with an Arduino Uno or Mega. They power up the Arduino through the Vin power providing 12 V most of the time.

If you use a motor shield that works in this way you will break your Yun. To make it working you need to bend the Vin pin and power your Yun separately.

Additionally, the 5V pin on the Yun is designed to provide power and not for powering the board.

The schematic for that shield is a bit hard to follow. But it looks like it is not trying to power the Yun through the 5V pin as long as J4 is removed. However, in this case, the power from the 5 volt pin (which is an output that is actually closer to 4.5 volts) is being routed to the VCC pin of all of the 4-pin Grove connectors. That means the Yun's limited power is driving all of those connectors. Not the best arrangement.

Maybe it would be best to isolate the 5V pin going to the Yun (clip it off or bend it out of the way) and keep J4 in place. That will power the shield's Grove connectors from the shield's on-board 5V regulator, and let the Yun be powered on its own.

As Angelo said, this is one of those boards that assumes it can power the Arduino by feeding 5V through that pin. The Yun doesn't work that way.

Actually, looking at the Yun schematic, there is a diode that prevents feeding power into the board through the 5V pin. Since this board would be trying to feed 5V to the diode against the Yun's 4.5V, the diode would be reverse biased, and no current would flow.

It might be safe, but keep J4 in place so the Yun doesn't try to power those connectors.

Can anybody else take a look at the schematics and verify this?

@ShapeShifter Yes you are right, you can't feed power from the 5V pin. The only way to provide power to the Yun is from the Vin pin but you must provide 5V.

Actually, I was talking more about the shield's schematic. I'm pretty sure he's safe from the Yun's point of view, I just want to make sure there aren't any issues with other pins the shield may be using.

I notice that the D0 and D1 pins (essential for Bridge communications) are routed on the shield. But it looks like they only go to a couple of the Grove connectors. So, to prevent conflicts, nothing should be plugged into the UART or J13 sockets.

It looks like the shield should be safe with the Yun, but I'm definitely not the final word on the subject, and plugging in any shield is always at your own risk. If it were me, I'd give it a try, but you have to make that decision for yourself and take responsibility for it. (I won't replace your boards if it gives trouble.)

Thanks for everyone's input. I tried it, everything is working fine, I'm powering the device through the yun and not the shield though. I'm not going to try that. Thanks again!

didannl: Thanks for everyone's input. I tried it, everything is working fine, I'm powering the device through the yun and not the shield though. I'm not going to try that. Thanks again!

@didannl, can you please post what you did to make it work, so that others coming later can benefit your solution. TIA Jesse