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Stacking motor shields and Arduino power question
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Stacking motor shields and Arduino power question

by motorcyclist on Mon Mar 22, 2021 7:39 pm

Hi all,
I'm using an Arduino Uno and a single Adafruit motor shield v2.3 to control 4 small vibration motors (~1A each) for a gaming seat:
1) Arduino is powered only from USB
2) motor shield is powered with a DC power (15V 6A) to the VIN input. Vin jumper removed.
They work perfectly fine.

Now I want to control 2 more vibration motors (same as the other 4). I know I'll need a 2nd motor shield to stack on top of the existing one and with address jumper set to a different address than the 1st shield.

My questions are:

1) Can this 2nd motor shield take power from the 1st shield (i assume with VIN jumper installed on the 2nd shield?) ???

2) If not, can I move the DC (15V 6A) from the 1st shield to the arduino and then have both shields take power from it (with VIN jumper installed)?

I really don't want to split the DC to each of the shield if I don't have to. Too cumbersome.

Thank you for any comments.
mike-

motorcyclist
 
Posts: 7
Joined: Mon Mar 22, 2021 7:30 pm

Re: Stacking motor shields and Arduino power question

by dastels on Mon Mar 22, 2021 8:43 pm

No, the Vin jumper on each shield has one side connected to Vin on the UNO. I don't see an alternative to wiring your 15v supply to each shield. Given that the power connector is on the board you should be able to make a "forks" out of heavier wire to connect 15v/gnd of each shield, and solder the supply wires to them.

Dave

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Re: Stacking motor shields and Arduino power question

by motorcyclist on Mon Mar 22, 2021 9:08 pm

Thanks Dastels, appreciate your reply. I didn't know how the shield jumper connects. I got it now.
One more question: if I understand correctly, the DC power to the VIN connector of the shield feeds straight to all 4 motors, as is, yes?
mike-

motorcyclist
 
Posts: 7
Joined: Mon Mar 22, 2021 7:30 pm

Re: Stacking motor shields and Arduino power question

by dastels on Mon Mar 22, 2021 9:13 pm

The jumper connects the motor power to Vin on the UNO which is the higher of 5v (from the USB connector) and whatever is at the barrel jack.

Vin is fed to all 4 motors IFF the Vin jumper is in place.

Dave

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Re: Stacking motor shields and Arduino power question

by motorcyclist on Fri Mar 26, 2021 12:23 pm

adafruit_products_mshielddiag.png
adafruit_products_mshielddiag.png (6.31 KiB) Viewed 305 times


Thank you Dastels, I appreciate your help.

I just ordered a 2nd Adafruit motor shield v2.3 and the stacking header so I can add more DC motors to my gaming seat.

Is the following correct?

1) I will have the Arduino and 2 stacking motor shields (let's say #1 is on top of arduino and #2 is on top of the #1)
2) I can connect a DC power input to the round VIN of the Arduino, then install the JP1 vin jumper of #1 so it takes power from Arduino dc
3) Now I connect a single wire from the + side of #1 VIN (JP2) to the + side of #2 VIN (JP2), then remove the JP1 VIN jumper of #2 (I assume the - ground wire from #1 to #2 is not needed as they are grounded together when stacking)

Is my understanding correct?
Here is a diagram from the Adafruit page that my understanding came from :-)

Thank you!
mike-

motorcyclist
 
Posts: 7
Joined: Mon Mar 22, 2021 7:30 pm

Re: Stacking motor shields and Arduino power question

by dastels on Fri Mar 26, 2021 2:34 pm

What you describe will work, but...

If you want to power both shields from the Arduino's barrel connector, you can just have the JP1 jumper installed on both shields and ignore the JP2 Vin connections on the shields. My suggestion to connect them was in the case that you were going to use a second, external power supply for the motors. Which is a good idea for multiple reasons. In that case you would remove both JP1 jumpers, and connect all the shields's JP2 power connectors to the external supply (+ sides together and to + of the power supply, likewise with the ground sides.

Dave

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Re: Stacking motor shields and Arduino power question

by motorcyclist on Fri Mar 26, 2021 2:46 pm

Thank you Dave! Appreciate your help.
mike-

motorcyclist
 
Posts: 7
Joined: Mon Mar 22, 2021 7:30 pm

Re: Stacking motor shields and Arduino power question

by motorcyclist on Fri Mar 26, 2021 11:47 pm

dastels wrote:What you describe will work, but...

If you want to power both shields from the Arduino's barrel connector, you can just have the JP1 jumper installed on both shields and ignore the JP2 Vin connections on the shields. My suggestion to connect them was in the case that you were going to use a second, external power supply for the motors. Which is a good idea for multiple reasons. In that case you would remove both JP1 jumpers, and connect all the shields's JP2 power connectors to the external supply (+ sides together and to + of the power supply, likewise with the ground sides.

Dave


Hi Dave,
Anything wrong about only plugging the power to the arduino and have it supply power to both motor shields? Each motor is about 330 ma.
Thanks.
mike

motorcyclist
 
Posts: 7
Joined: Mon Mar 22, 2021 7:30 pm

Re: Stacking motor shields and Arduino power question

by dastels on Sat Mar 27, 2021 10:32 am

You can try it. It may work ok, but motor noise may be more of an issue. There are things you can do to minimize that, but even so with enough motors it might be overwhelming. You can find a lot about it online, here's once page: https://www.pololu.com/docs/0J15/9.

Dave

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