Stacking shields?

Hi. I seem to have hit another road block in my construction, and with my self given deadline closing in, I need to make things work fast. I have everything set up other than the fact that my robot frame has four motors, and if I drive two, it doesn't work. This results in me needing to add another shield? To control the other two motors in the back? However, I am using a seeed studios v2 motor shield. Can I stack these, and if so, how would the outputs work? :astonished: ;D

checking the specs ( I found here ) It appears that the shield uses pins 8,9,10,11,12,13. So stacking two on top of each other is going to cause conflict on those pins.

I'd suggest you modify one of your shields to use pins 2,3,4,5,6,7 instead. This could probably be achieved by removing the pin header (from 8-13) and soldering jumper wires in their place. These could then be connected to the appropriate pins to sort out the hardware issue.

I haven't looked at the library files but if you feel up to the challenge of sorting out this hardware issue then I could possibly dig further on the codiing issues.

I really appreciate your help. Is there any way I can make four motors drive with one shield? Or make the two front wheels be able to pull the back, not driven wheels? Here is my code-

int lm1 = 8 ;

int lm2 = 11;

int lms = 9;

int rm1 = 12;

int rm2 = 13;

int rms = 10;

void setup()

{

pinMode(lm1,OUTPUT);

pinMode(lm2,OUTPUT);

pinMode(lms,OUTPUT);

pinMode(rm1,OUTPUT);

pinMode(rm2,OUTPUT);

pinMode(rms,OUTPUT);

}

void loop()

{

analogWrite(lms,255);

analogWrite(rms,255);

digitalWrite(lm2,LOW);

digitalWrite(rm2,LOW);

digitalWrite(lm1,HIGH);

digitalWrite(rm1,HIGH);

delay(5000);

digitalWrite(lms,LOW);

digitalWrite(rms,LOW);

delay(2000);

analogWrite(lms,200);

analogWrite(rms,200);

digitalWrite(lm1,LOW);

digitalWrite(rm1,LOW);

digitalWrite(lm2,HIGH);

digitalWrite(rm2,HIGH);

delay(5000);

}

I really appreciate your help again, and I really would like to get this thing working using only two motors.

In addition to this, how'd this guy get it to work with only one motor shield? http://www.robotliving.com/building-robots/four-wheeled-robot/

You don't mention what type of motors you have.

I bought them in a kit with the pirate 4wd compatible frame. It just says hobby motors. I think 3-12 volt?

goacego: In addition to this, how'd this guy get it to work with only one motor shield? http://www.robotliving.com/building-robots/four-wheeled-robot/

I think you'll find he's connected both left hand motors together in parallel and both right hand motors together. So, as far as the board is concerned, he just has two motors connected (right and left).

This is why he gets that sliding business instead of proper steering.

so I take four wires, and turn it into two?

how do i do that? i'm really new sorry

ok, so i just figured out I can drive it with 9v battery going through the motor, but how do i make it so the uno shoots 9vs into it

goacego: so I take four wires, and turn it into two?

Yes. Instead of putting one red wire into a terminal you put two red wires into that same screw terminal (one from the back motor, one from the front). You then do the same with the black wires. Both front and back motors connect to the same terminal.

Then for the motors on the other side you do exactly the same.

It's not an ideal solution but I don't see any other way of driving 4 motors with that shield.

Thank you so much! I really appreciate your help!

Ok. that didn't work. at all now all the motors are going really, really, slowly and weakly, sometimes not at all.

What are you using to provide power to the motor shield?

KenF: What are you using to provide power to the motor shield?

He mentioned a 9V battery, so he's probably using a PP3. :disappointed_relieved:

goacego:
In addition to this, how’d this guy get it to work with only one motor shield?
http://www.robotliving.com/building-robots/four-wheeled-robot/

Maybe he’s using an Adafruit motor shield.

Henry_Best: He mentioned a 9V battery, so he's probably using a PP3. :disappointed_relieved:

That's what I was afraid of.