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91  Community / Bar Sport / Re: KUDOES to Amazon.com!!! on: September 20, 2013, 02:08:35 pm
Amazon prime is the way to go. I just ordered some LED's for like 3$ with free two day shipping.
92  Using Arduino / Project Guidance / Re: How to detect a coin falling? on: September 20, 2013, 02:03:10 pm
Just plug the LED into power/ground… don't for get the resistor! The longer leg should be + I think.

 For the photo resistor read the link below.


http://arduino.cc/en/Reference/AnalogRead
93  Using Arduino / Motors, Mechanics, and Power / Re: 24v H-bridge for wheelchair motors on: September 20, 2013, 01:53:14 pm
I'm about to start building a motor control for a amp flow motor and at 285amps they are a beast! I was considering using a few mosfets…
http://ec.irf.com/v6/en/US/adirect/ir?cmd=catSearchFrame&domSendTo=byID&domProductQueryName=IRFB7437

Perhaps they would work for you. They are only a $1 each!
94  Using Arduino / Project Guidance / Re: How to detect a coin falling? on: September 20, 2013, 01:40:09 pm
What about a led (or laser)  and photo resister? When the coin slides down less light will shine on the photo resistor. And the best part is you probably already have the stuff!
95  Using Arduino / Installation & Troubleshooting / Re: Is my Arduino Uno genuine? on: September 18, 2013, 08:53:56 pm
Does it say "made in Italy" or "designed in Italy?" Real Arduino's say "made in Italy." Also, Just because it is fake does not mean that it will not work…
96  Community / Bar Sport / Re: Best digital multimeter? on: September 18, 2013, 08:46:35 pm
I think I will go with the fluke 117 as it seems to be a good deal.

http://www.amazon.com/Fluke-117-Electricians-True-Multimeter/dp/B000O3LUEI/ref=cm_cr_pr_product_top
97  Using Arduino / Motors, Mechanics, and Power / Re: How to make 2 dc motors move together using motorshield? on: September 17, 2013, 10:39:22 pm
Quote
It sounds to me like you power supply can not supply enough current for two motors.

Or his motor driver is not able to handle the load and is starting to act up. Perhaps one of the motor uses up more current do to some mechanic flaw in his robot/car and the motor driver is not able to handle it. He said the motor driver is buzzing, not the motors. Then again it could be the power supply. Who knows when we have no specs.

@ timlee we need to know what motor driver, motor, and power supply your using.

Best of luck!
98  Using Arduino / Motors, Mechanics, and Power / Re: Mounting a Wheel to the DC Motor on: September 17, 2013, 03:43:21 pm
Quote
What do you guys do for making the body parts as well?

1. I design a frame and have a welder make it from me.

2. I make a design on inkscape and have it laser cut.

3. I buy a pre made kit.
99  Using Arduino / Motors, Mechanics, and Power / Re: How to make 2 dc motors move together using motorshield? on: September 17, 2013, 03:38:19 pm
Quote
Hi I am using an arduino uno stacked with a motorshield.

It would help if we knew which one!
100  Topics / Robotics / Re: How to make wall/obstacle avoiding robot with arduino uno atmega 328 on: September 15, 2013, 11:38:52 am
Sorry I did not notice. I put the code together a little to fast. smiley I will update my post soon.

I'm a little confused. That is how your code was. I just copied it in. Does it work like that...

Code:
int ENA=5;//connected to arduino's port 5 (output pwm)
int IN1=2;//connected to arduino's port 2
int IN2=3;//connected to arduino's port 3
int ENB=6;//connected to arduino's port 5 (output pwm)
101  Topics / Robotics / Re: Wheel Placement on Robot on: September 14, 2013, 03:43:45 pm
95% of the weight of the robot will be in the center so I don't think it will tip. Thanks for your help. I will post photos once the robot is built as well as the results.



102  Topics / Robotics / Re: Wheel Placement on Robot on: September 14, 2013, 02:05:06 pm
Something like that would be fine. The price is also much cheaper smiley Like I said I don't have the caster wheels.

This one might work. http://www.amazon.com/Swivel-Caster-Pneumatic-Wheel-Brake/dp/B005UZ4FQA/ref=sr_1_14?ie=UTF8&qid=1379185406&sr=8-14&keywords=Pneumatic+Wheels+Casters


Before I buy them I need to know if  this design work. Am I right that when calculating torque you add up the torque of all the motors thus 4 drive wheels will have 2x the torque of a 2 drive wheels?

Thanks!
103  Topics / Robotics / Re: Wheel Placement on Robot on: September 14, 2013, 01:35:43 pm
Quote
If you mean 4WD with the drive wheels close together, and 2 casters on the ends, that sounds doable, but I don't see a situation where that design will be at all useful. IE, why even bother with 4WD?

Yes that is what I mean. The only reason I'm doing it that way is that I have 4 of the same motors. If I understand torque correctly using  4 drive wheels will double the torque the robot would have if It was using only 2 drive wheels. To push the robot up the needed incline (I don't remember what it was off the top of my head) two of the motors I have will not have enough torque. That is why I need four drive wheels.

Quote
I think a lot depends upon where this robot will operate most of the time. If outdoors on earthen terrain, I don't think having casters is a good idea at all, as they will probably dig into the dirt a lot. For that, I would go with a basic design with 4 drive wheels on the corners of the robot, and relie on a very robust motor/wheel system to keep it from breaking down.

The caster wheels will be fine (link below). Also, I was going to put the drive wheels towards the center to improve the turning. I don't believe the motors will break. I need the turns to be exact when its driving autonomously and I think this design will give me the needed torque and turning capability.


http://www.trossenrobotics.com/store/p/5881-Parallax-Caster-Wheel-Kit.aspx
104  Topics / Robotics / Re: How to make wall/obstacle avoiding robot with arduino uno atmega 328 on: September 14, 2013, 12:48:50 pm
That code should make your robot turn when something gets closer then 10 inches. Try it and see if it works. Also please do what oric_dan said.

Quote
1. wrap your code using the "#" icon on the edit screen,


Code:

 
 
 int ENA=5;//connected to arduino's port 5 (output pwm)
int IN1=2;//connected to arduino's port 2
int IN2=3;//connected to arduino's port 3
int ENB=6;//connected to arduino's port 5 (output pwm)
int IN3=4;//connected to arduino's port 4
int IN4=7;//connected to arduino's port 7

const int trigPin = 13;
const int echoPin = 12;
 
void setup() {
  // initialize serial communication:
  Serial.begin(9600);
}
 
void loop()
{

 analogWrite (ENA,200);//start driving motorA
  analogWrite (ENB,200);//start driving motorB

  // establish variables for duration of the ping,
  // and the distance result in inches and centimeters:
  long duration, inches, cm;
 
  // The sensor is triggered by a HIGH pulse of 10 or more microseconds.
  // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
  pinMode(trigPin, OUTPUT);
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
 
  // Read the signal from the sensor: a HIGH pulse whose
  // duration is the time (in microseconds) from the sending
  // of the ping to the reception of its echo off of an object.
  pinMode(echoPin, INPUT);
  duration = pulseIn(echoPin, HIGH);
 
  // convert the time into a distance
  inches = microsecondsToInches(duration);
  cm = microsecondsToCentimeters(duration);
  
  Serial.print(inches);
  Serial.print("in, ");
  Serial.print(cm);
  Serial.print("cm");
  Serial.println();
  
if ( inches < 10) {
  
  
  analogWrite (ENA,255);//start driving motorA
  analogWrite (ENB,1);//start driving motorB
  
  delay (500);
  
}



}
 
long microsecondsToInches(long microseconds)
{
  // According to Parallax's datasheet for the PING))), there are
  // 73.746 microseconds per inch (i.e. sound travels at 1130 feet per
  // second).  This gives the distance travelled by the ping, outbound
  // and return, so we divide by 2 to get the distance of the obstacle.
  // See: http://www.parallax.com/dl/docs/prod/acc/28015-PING-v1.3.pdf
  return microseconds / 74 / 2;
}
 
long microsecondsToCentimeters(long microseconds)
{
  // The speed of sound is 340 m/s or 29 microseconds per centimeter.
  // The ping travels out and back, so to find the distance of the
  // object we take half of the distance travelled.
  return microseconds / 29 / 2;
}
105  Topics / Robotics / Re: Wheel Placement on Robot on: September 14, 2013, 11:22:27 am
Quote
What I was referring to is, a heavy robot with tripod arrangement and only 1 caster can easily tip over.

I agree! That's why I thought that a caster on each end would prevent it form tipping. Would my idea for a 6 wheel robot work?
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