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1  Community / Products and Services / Re: Amazing Sale...Arduino's for $3!!! on: April 02, 2014, 07:53:23 pm
I was one of the lucky few who got  7 Arduino boards (4 Pro Micro's, 2 Pro's and a Red Board) before they sold out! I was up until 2 :00 in the morning waiting for the sale to start, but it was worth it!


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I wonder how fast Sparkfun will restock, and whether you could get a similar clone from a Chinese vendor faster than from Sparkfun

I will not buy fakes because most of them violate the Arduino trademark which is illegal. They don't contribute any money to the Arduino project, and many are made with less reliable parts.
2  Community / Products and Services / Amazing Sale...Arduino's for $3!!! on: March 29, 2014, 10:24:23 am
Huge Arduino Sale.... Figured I would share it with everybody! When is the last time you got an Arduino for $3? I ordered 8!

https://www.sparkfun.com/news/1439
3  Topics / Product Design / Re: Box top counter on: March 17, 2014, 10:23:44 pm


 Like the others have said I would go with a short say 2 ft conveyor belt. Then have a robot aren using this gripper...http://www.lynxmotion.com/p-825-vacuum-gripper-kit-with-wrist-rotate.aspx

Then you could have it place several on a scanner and you could create some software on the computer to make a grid (each box top would be a box in the grid) and assign a value to each box. The robot arm could then easily sort them and place them into a box to be shipped out.

Best of Luck!
4  Using Arduino / Project Guidance / Re: Voting-based LED control? on: March 02, 2014, 12:00:50 pm
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And there are 3 users controlling them.


Do you have three different Arduinos or three buttons on one Arduino?
5  Topics / Robotics / Re: Desktop Rover on: February 28, 2014, 02:29:07 pm
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1. Would the best way to make it not roam off be to put a distance sensor on the bottom and make the threshold so that if the distance is greater than the distance between the bottom and my desk, so that if the distance is greater it knows it is almost off the edge?

That sounds good, but I would consider  using two.



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2. I have an old lith-ion battery from a kyocera cell phone, Would it be possible for me to use this as a battery source for the rover?

How would you charge it? Also, the battery you use will be dictated by the voltage your motors run on. My  guess is that It would not work.
6  Topics / Robotics / Re: Does a PowerWheels motor need to be powered by a chunky 6v? on: February 21, 2014, 09:59:32 am
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Not sure I understand why to use an AC-DC converter if the motor is a DC motor? And how is it that I could use the charger?

If your project is not portable, and is near a wall outlet you can use a AC-DC converter to power the motor. The converter will take the AC power from the wall and turn it into DC power for your motor. If you just have standard changer (not one for Lithium batteries) you can just plug the motor into the charger and you should be good to go.



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I'm thinking this motor may be overkill for my project. I think I'll start a new topic then with the full description of my project because there are obviously a number of options and I really have no clue which way to go. Thanks for your input and please watch for my new post.

Sounds good.
7  Topics / Robotics / Re: Does a PowerWheels motor need to be powered by a chunky 6v? on: February 18, 2014, 07:34:34 pm
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I have no idea how many amps this motor will require and no way to test it.

Well then you will have to buy a multimeter. Not really anyway around that unless you have a part number or wattage rating. If you want us to give you a general range then we wold need a photo, and your application.... Take the Ampflow motor I'm using right now in my robot. Under no load it draws around 3 amps. At stall it sucks 300 amps! I My estimate is it's typical usage will be 40 amps.   Anyway if you want an estimate tell us what your doing and send us a photo.

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The switch wired to the motor is rated at 16A/12V - I think that means it can provide up to 16 amps powered by a maximum of 12 volts.
Again not that helpful. For their application thats all they need, but for what your doing you might want more from the motor.

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Is it possible to power it using an Arduino Uno R3 with an L293D Motor Drive Shield and 6xAA battery pack?

Not a chance. The motor Driver can not even output 1 amp! The batteries will hardly last any time. For a motor driver you going to need something on the mid section of this page, or more.

http://www.orionrobotics.com/Motor-Controllers_c_125.html



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Basically, I am trying to determine if I must buy a big 6v battery - is this the only way to power this motor?

No. You could buy a Ac-DC converter (the charger might even work), or you could buy a lithium based battery (small, but more $$$).
8  Using Arduino / Sensors / Re: onboard speed sensing on: February 18, 2014, 01:35:25 pm
1. It appears that your using a plane, but I'm not sure. If your using a car I would use motor encoders.

2.
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think of a falling rc plane....... how would it distinguish that from say flying down under control


A falling plane will likely be in a spiral which would be easy to pick up with gyro + accelerometer. Add in the fact that there will also be other signs of a problem... fuel/battery running low, motor issues, ect. and it would be dead easy.



 3.
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I... would like my device to know when it is moving above 5mph

It would be possible, not accurate,  to do that with an  accelerometer. I would buy or build a Air speed indicator (assuming this is on a plane).   
9  Using Arduino / Project Guidance / Re: Coding help; ultrasonic sensor on: February 18, 2014, 01:12:40 pm
Hello, I will show you how to do that. Taking an average reading over a small period of time could also help.


Code:
if (distance < 40 ) {   // distance set to 45 cm
  
  if (distance > 5 ) {

    Serial.println (distance); // diagnostic for when connected to computer
     //brake drive motor and pause 1/10 second
    digitalWrite(9, HIGH);
    delay(100);

    //
    //setting turn motor
    //
    
    //turn off brake for turn motor
    digitalWrite(8, LOW);

    //set turn motor direction
    digitalWrite(13, HIGH);
    //activate turn motor
    analogWrite(11, 255);
    
    //
    //setting drive motor
    //
    
    //turn off brake of drive motor
    digitalWrite(9, LOW);
    
    //set drive motor backwards direction
    digitalWrite(12, LOW);
    
    //activate the drive motor
    analogWrite(3, 200);

    
    //backup for 2 seconds
    delay(2000);
    
    //
    //stopping
    //
    
    //brake both motors
    digitalWrite(8, HIGH);
    digitalWrite(9, HIGH);
    
    }
  }
  





Or this (probably best option)


Code:
 if (distance < 40 && distance > 5  ) {   // distance set to 45 cm
    Serial.println (distance); // diagnostic for when connected to computer
     //brake drive motor and pause 1/10 second
    digitalWrite(9, HIGH);
    delay(100);

    //
    //setting turn motor
    //
    
    //turn off brake for turn motor
    digitalWrite(8, LOW);

    //set turn motor direction
    digitalWrite(13, HIGH);
    //activate turn motor
    analogWrite(11, 255);
    
    //
    //setting drive motor
    //
    
    //turn off brake of drive motor
    digitalWrite(9, LOW);
    
    //set drive motor backwards direction
    digitalWrite(12, LOW);
    
    //activate the drive motor
    analogWrite(3, 200);

    
    //backup for 2 seconds
    delay(2000);
    
    //
    //stopping
    //
    
    //brake both motors
    digitalWrite(8, HIGH);
    digitalWrite(9, HIGH);
    
    
  }
  
10  Topics / Robotics / Re: R/C Rover 5 platform on: February 16, 2014, 10:18:55 am
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I am thinking of using along the lines of this: https://www.sparkfun.com/products/11759
Why implications would this have on the sketch/ wiring up?


The remote control does not work by it's self. When the Arduino receives the signal from the remote via a IR receiver it then has to decide how to act... which requires a sketch.  Spark fun gives you an example sketch for it.. https://www.sparkfun.com/products/11761



As for wiring you need to connect a PWM pin on your Arduino to each pin on the board that says PWM. Then take a regular digital output on your Arduino like 13,12,8,7 (just not 1/2) to each pin marked DIR . Then take each pin marked CUR on the board to a Analog input on your Arduino (this is optional). Then tie the ground and 5v of your Arduino into the board. The gnd/ 5v pins are on the top right by motor 4 output. 

Here is some example code that should get you started. It does not use the cur pins or the encoders, but It should drive your robot around and give you a place to start.


Code:
const byte P1 = 11; // Pin on arduino (left motor)
const byte P2 = 10;// Pin on arduino (left motor)
const byte P3 = 9;  // Pin on arduino    (right motor)                   
const byte P4 = 6;   // Pin on arduino  (right motor)

const byte M1 = 13;// Pin on arduino (left motor)
const byte M2 = 12;// Pin on arduino (left motor)
const byte M3 = 8;  // Pin on arduino     (right motor)                 
const byte M4 = 7;   // Pin on arduino     (right motor)                   

void setup()
{
  pinMode(M1, OUTPUT);   // set as output
  pinMode(M2, OUTPUT);  // set as output
  pinMode(M3, OUTPUT);    // set as output
  pinMode(M4, OUTPUT);  // set as output

  pinMode(P1, OUTPUT);    // set as output
  pinMode(P2, OUTPUT);  // set as output
  pinMode(P3, OUTPUT);    // set as output
  pinMode(P4, OUTPUT); // set as output
}

void loop()
{

  digitalWrite(M1,LOW);   //direction control
  digitalWrite(M2,LOW);   //direction control
  digitalWrite(M3,LOW);   //direction control
  digitalWrite(M4,LOW);   //direction control
 
  analogWrite(P1, 250);   //PWM Speed Control (fast)
  analogWrite(P2, 250);   //PWM Speed Control ( fast)
  analogWrite(P3, 250);   //PWM Speed Control (fast)
  analogWrite(P4, 250);   //PWM Speed Control ( fast)
   delay(2000); // delay 2 sec
   
  digitalWrite(M1,HIGH);   //direction control
  digitalWrite(M2,HIGH);   //direction control
  digitalWrite(M3,HIGH);   //direction control
  digitalWrite(M4,HIGH);   //direction control
 
  analogWrite(P1, 250);   //PWM Speed Control (fast)
  analogWrite(P2, 250);   //PWM Speed Control ( fast)
  analogWrite(P3, 250);   //PWM Speed Control (fast)
  analogWrite(P4, 250);   //PWM Speed Control ( fast)
     delay(2000); // delay 2 sec
   
  digitalWrite(M1,HIGH);   //direction control
  digitalWrite(M2,HIGH);   //direction control
  digitalWrite(M3,HIGH);   //direction control
  digitalWrite(M4,HIGH);   //direction control
 
  analogWrite(P1, 150);   //PWM Speed Control (slower)
  analogWrite(P2, 150);   //PWM Speed Control ( slower)
  analogWrite(P3, 150);   //PWM Speed Control (slower)
  analogWrite(P4, 150);   //PWM Speed Control ( slower)
 
  delay(2000); // delay 2 sec
   
  digitalWrite(M1,LOW);   //direction control
  digitalWrite(M2,LOW);   //direction control
  digitalWrite(M3,HIGH);   //direction control
  digitalWrite(M4,HIGH);   //direction control
 
  analogWrite(P1, 150);   //PWM Speed Control (slower)
  analogWrite(P2, 150);   //PWM Speed Control ( slower)
  analogWrite(P3, 150);   //PWM Speed Control (slower)
  analogWrite(P4, 150);   //PWM Speed Control ( slower)
 
     delay(2000); // delay 2 sec

}




 Once you get that working you can add in the encoders with this library...
http://www.pjrc.com/teensy/td_libs_Encoder.html
11  Topics / Robotics / Re: Mirobot: an open source WiFi drawing bot on: February 15, 2014, 11:26:17 am
That looks cool! How long until you hit production?
12  Topics / Robotics / Re: R/C Rover 5 platform on: February 15, 2014, 11:24:58 am
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that is remote controlled using arduino

What remote control/ receiver???  That completely changes how the program will work. If you don't have one I would go with an xbee system (long range) or Ir(short range). Sparkfun sells a nice Ir kit for cheap.  If you have your remote control let us know what kind it is.
13  Topics / Robotics / Re: Where do I go? Robot Idea on: February 14, 2014, 11:13:21 am
As far as the motors go I would look into Ampflow or AME. Paralllax sells a kit with AME motors that gives you the wheels and mounts. As far as steering I would go for 4WD. It would make turning extremely easy.
14  Using Arduino / Programming Questions / Re: Encoder + Motor Not working on: February 14, 2014, 11:07:22 am
Ok. So it turns out that  of my brand new encoders that I bought form parallax over 50% of them don't work. I finally found that buy unplugging  them them from the Arduino and testing each one with my multimeter.  I will be getting new ones (not from parallax).


Anyway I have a question with interrupts as far as the programing goes. From what I can tell when the state changes on one of the interrupts the Arduino breaks out of the current code and adds a count to the encoder. Will that affect the rest of a program?


Thanks!

15  Using Arduino / Programming Questions / Re: Encoder + Motor Not working on: February 13, 2014, 09:59:50 pm
Tested it with an Uno and it still did not work....
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