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16  Using Arduino / Motors, Mechanics, and Power / Re: L298N Motor Driver board smoking.... on: August 05, 2013, 09:38:06 pm
Thx much for the info.
Wow, does it really need 60 amps? That seams pretty high...
17  Using Arduino / Motors, Mechanics, and Power / Re: L298N Motor Driver board smoking.... on: August 05, 2013, 09:03:50 pm
OK here is the only info on the motors...
18  Using Arduino / Motors, Mechanics, and Power / Re: L298N Motor Driver board smoking.... on: August 05, 2013, 04:02:53 pm
What am I building...? That's a good question.
No, it's not really a secret, just a little odd & hard to explain.
I'm competing in a CANstruction competition. We build large sculptures out of canned food, they're on display for a week, then donated to the local food bank. This year we're building a 6' Rubik's cube where the top 2 levels will rotate.

Here's a preview:


And attached is the layout of the system. The motors shown in the layout are out of date. My smaller inadequacy motors.

It's going to have to rotate a lot of weight, maybe 1,500-1,800 lbs. So that's why I want 3 motors on the lower level & 2 on the upper. But like you said start out slow... then I think it should have enough torque.

I was thinking since I only have 2 levels of rotation, that all the motors on that level could share a channel on the controller...
But I'm not sure if that works with the amp requirements or not...
19  Using Arduino / Motors, Mechanics, and Power / Re: L298N Motor Driver board smoking.... on: August 05, 2013, 03:08:51 pm
Thx for the info guys. I'll get back to you tonight or tomorrow with more info.

I'd like to drive a total of 4 (maybe 5) motors, but they're spit into 2 sets.
So 2 or 3 would always be going in the same direct & speed and the other 2 could be going a different direct & speed.
So I'm thinking I only need a 2 channel controller, right?
20  Using Arduino / Motors, Mechanics, and Power / Re: L298N Motor Driver board smoking.... on: August 05, 2013, 02:21:22 pm
I'll have to check again when I get home if I can find more info on the power requirements.
Yes, it still runs with the smaller motors connected.
Can you suggest another motor controller?
I found this one: http://www.robotshop.com/pololu-dual-motor-driver-shield-arduino-2.html
12A, 24V, would that work?

thx for the help,
Barry
21  Using Arduino / Motors, Mechanics, and Power / Re: L298N Motor Driver board smoking.... on: August 05, 2013, 02:04:58 pm
I'm not actually sure, there's no model number on the motor itself, so I'm not sure how to look it up.
All it says is MP-3C Red, but that's the model number for the wheelchair not the motor. Is there another way to figure out what it needs?
22  Using Arduino / Motors, Mechanics, and Power / L298N Motor Driver board smoking.... on: August 05, 2013, 01:27:18 pm
So I previously setup my Arduino Mega with this L298N Motor Driver board http://yourduino.com/sunshop2/index.php?l=product_detail&p=127.
I used some 12v motors off of some kids/power wheels cars & they worked great. Now I want to upgrade my motors. So I got some 24v electric wheelchair motors, sim. to this: http://www.ebay.com/itm/Merit-power-chair-right-motor-gearbox-PC-MP3-R14-AR-/111135604269?pt=LH_DefaultDomain_0&hash=item19e032be2d

Even though the motor is 24v, if I connect it to a 12v battery, it seams to run fine (maybe at 1/2 speed).
But when I connected it to my L298N Motor Driver board, the chip started to smoke & the motor was turning very slow, even though I had my speed pin set to 255. Can anyone tell me what I'm doing wrong?
The L298N Motor Driver board says it can take up to 35v, but I'm only putting 12v through it, so I didn't think that would over heat it....

Thanks for any help,
Barry
23  Using Arduino / Programming Questions / Re: Ping-Pong with a DC motor & a pot on: October 10, 2012, 01:19:47 pm
You won't believe what I'm building. :-)
It's a giant R2-D2 sculpture built out of canned food.
It's for a charity event called CANstruction. http://www.sfcanstruction.org
R2 will be 7' tall with a 3' dia. body.
All this coding is to get his head to turn.
I know R2's head should turn 360 deg. but my pot. only turns 270 deg. & I don't want to deal with winding/unwinding the wires.
Unfortunately my current motor is under sized & can't turn the head with much load on it, so I can't answer your questions about have long it's taking to turn it.
I have 2 larger motors on order now. Maybe you'll be right & I can put it back to only have the maxSpeed at the midPoint...
24  Using Arduino / Programming Questions / Re: Ping-Pong with a DC motor & a pot on: October 10, 2012, 12:22:43 am
I was just wondering, instead of only having the maxSpeed at the exact midpoint, how could I get it to stay at the maxSpeed for the center 1/3 of the rotation?
So the 1/3's would look something like this:  minSpeed -> maxSpeed | maxSpeed -- maxSpeed | maxSpeed -> minSpeed
25  Using Arduino / Programming Questions / Re: Ping-Pong with a DC motor & a pot on: October 09, 2012, 03:28:44 pm
Thank you very much for this detail explanation.
This is exactly how a noob like myself learns from the experts. :-)
26  Using Arduino / Motors, Mechanics, and Power / Re: Suggestions on where to buy a high torque 12v DC motor on: October 09, 2012, 03:26:36 pm
thx for the suggestions guys.
27  Using Arduino / Motors, Mechanics, and Power / Suggestions on where to buy a high torque 12v DC motor on: October 09, 2012, 12:08:50 pm
Hi guys,
I bought one of these: http://www.pololu.com/catalog/product/1107
but, it doesn't have enough power/torque for by project.
I need a motor that can turn about 100 lbs. at around 4-6 rpms under load.
Does anyone have any suggestions on where I can buy a motor that can do this without breaking the bank?

28  Using Arduino / Programming Questions / Re: Ping-Pong with a DC motor & a pot on: October 08, 2012, 04:05:28 pm
Yes. Make the speed depend on the absolute value of the difference between the headRot value and the middle of the range. As the difference gets larger, slow down. As it gets smaller, speed up. The maximum speed, then, would be right in the center of the range.

Could you give me a hint on how to code that?
29  Using Arduino / Programming Questions / Re: Ping-Pong with a DC motor & a pot on: October 08, 2012, 03:35:18 pm
Varying the motor speed as you get closer to the limit would be a good thing. That's what the PID idea is all about. Sneak up on the limits to avoid overshooting.

You only need to flip the motor direction if it changes, not on every pass through loop.

Your commented out Serial.print() information does not reflect reality.

Thanks for the info. So I should slow down the motor as I get closer to the limit?
30  Using Arduino / Programming Questions / Re: Ping-Pong with a DC motor & a pot on: October 08, 2012, 03:22:36 pm
You never actually do anything with dir or motors...

If the potentiometer values represent limits, names like MIN_something and MAX_something make more sense than two MAX_somethings.

Yes I was just testing to make sure I got the logic correct before connecting to the motor. Here it is with the motor code. Thanks for the tip on the MIN/MAX..

Code:
#define  POT_PIN   A8
#define  MAX_LEFT  750
#define  MIN_RIGHT 300

//Motor A
int dir1PinA = 32;
int dir2PinA = 34;
int speedPinA = 36;
int motor_speed = 250;
int dir = 0; // 0 = Left, 1 = Right

void setup() {
  Serial.begin(9600); 
}

void loop() {
 
  int headRot = analogRead(POT_PIN);
 // Serial.println(headRot); // read-print pot
  analogWrite (speedPinA, motor_speed); //Turn motor on
 
  if (headRot < MAX_LEFT)
  {
    if (headRot > MIN_RIGHT)
    {
     // Serial.println("Center");
    } else {
    //  Serial.println("Min Right");
      dir = 0;
    }
  } else {
   // Serial.println("Max Left");
    dir = 1;
  }
 
  flipMotorDirection(dir); 
}


void flipMotorDirection(int dir)
{
  if (0 == dir)
  {
    digitalWrite (dir1PinA , LOW);
    digitalWrite (dir2PinA, HIGH);
  }
  else
  {
    digitalWrite (dir1PinA, HIGH);
    digitalWrite (dir2PinA, LOW);
  }
}
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