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31  Forum 2005-2010 (read only) / Interfacing / Re: turret for a quad robot on: February 28, 2008, 05:24:10 am
Quote
AFAIK, with the ones limited to 180 you tell them where they should be and they go there.
So if you tell it to go to 45 degrees then it will work out how far to move in what direction by its self.

Makes it slightly easier dont you think? smiley-wink

Ok I get your point. Servo 360 doesn't work the same a servo with limited angle.
Thank you very much.
32  Forum 2005-2010 (read only) / Interfacing / Re: turret for a quad robot on: February 28, 2008, 04:44:39 am

Ok if I want the servo goes to -90 to 90. It is should be easy. But what happend if I want my servo goes from -45 to 45 and 45 to -45  many time (during one hour) ? After few minuits the servo starts to go more one left ou on the right... Do you think there is a way to recalibrate the servo ?
33  Forum 2005-2010 (read only) / Interfacing / turret for a quad robot on: February 28, 2008, 02:18:05 am
I have a problem to position the turret of my robot. I use a continuous 360 servo. I would like to position the servo for an angle between 0 and 180 degree. The goal is to have a kind of radar to detect the obstacle. So the turret should go on the left and on the right continuously.

At the beginning with a 360 servo, I get the good positions for my servo but after some time it is become difficult to know exactly the position of the servo.

So I plan to buy and use a servo with a limit angle to 180. But I would like to know if I will get the same problem? How I will know the position after many movement of the turret? Do you think I will lose some precision?


34  Forum 2005-2010 (read only) / Interfacing / Re: Controller for 4 servos on: October 07, 2007, 09:40:14 am
I find the problem  smiley-grin. I use a battery for the servo and an extern power for the arduino board. I connect the ground together and now everything works fine.
35  Forum 2005-2010 (read only) / Interfacing / Controller for 4 servos on: October 07, 2007, 05:53:32 am
I try to control 4 servos for rover. 2 servos for the left side and 2 for the right side. The servos on the same side works in the same rotation. I have a problemL The rotation of servo are not stable. If I put 1500microseconds for the neutral position, they move a little.

I connected directly on the arduino pin the wired of the servo. I should put a resistance ?

Code:
int sensorIR = 0;
int sensorUS = 1;
int calibIR = 10000;
int valIR;

int servoTU = 8;
int servoLF = 9;
int servoLB = 10;
int servoRF = 11;
int servoRB = 12;
int lastPulseR;
int lastPulseL;
int pulseWidthR = 1250;
int pulseWidthL = 1750;
int refreshTimeServoL = 20;
int refreshTimeServoR = 20;

void servoL(int pulseWidth){
 if(millis()-lastPulseL >= refreshTimeServoL){
  digitalWrite(servoLF,HIGH);
  digitalWrite(servoLB,HIGH);
  delayMicroseconds(pulseWidth);
  digitalWrite(servoLF,LOW);
  digitalWrite(servoLB,LOW);
  lastPulseL=millis();
 }
}

void servoR(int pulseWidth){
 if(millis()-lastPulseR >= refreshTimeServoR){
  digitalWrite(servoRF,HIGH);
  digitalWrite(servoRB,HIGH);
  delayMicroseconds(pulseWidth);
  digitalWrite(servoRF,LOW);
  digitalWrite(servoRB,LOW);
  lastPulseR=millis();
 }
}

int readSensorIR(){
  return (1000/analogRead(sensorIR));        
}
          
void setup(){
 pinMode(servoTU,OUTPUT);
 pinMode(servoLF,OUTPUT);
 pinMode(servoLB,OUTPUT);
 pinMode(servoRF,OUTPUT);
 pinMode(servoRB,OUTPUT);
 pinMode(sensorIR,OUTPUT);
 pinMode(sensorUS,OUTPUT);
 lastPulseL=millis();
 lastPulseR=millis();
}

void loop(){
  servoL(pulseWidthL);
  servoR(pulseWidthR);            
}

36  Forum 2005-2010 (read only) / Interfacing / Re: servo motor for a quad robots (4x4) on: August 09, 2007, 11:13:03 am
I started to make a diagram for my quad robot. I am not an expert. So, I would like to know, if there is a problem in my diagram. Do you think the 6v battery is enough for the 5 servos and the arduino ? Also, I don't know if I need resistances.

The diagram:
http://www.irit.fr/~Nicolas.Lassabe/diagram.jpg

The page of my quad robot:
http://www.irit.fr/~Nicolas.Lassabe/robot.php
37  Forum 2005-2010 (read only) / Interfacing / servo motor for a quad robots (4x4) on: August 03, 2007, 07:11:44 pm
Hi,
I would like to create a robot quad with 4 independent wheels.
I would like to get something like this but less expensive   :smiley  
http://cswww.essex.ac.uk/staff/lucas/roborace/roborace.html

I try to find a continuous rotation servomotor. I only find this one:
http://www.active-robots.com/products/motorsandwheels/servo-motors.shtml. The others Hitec, futaba need to be modified for the 360 rotation  :-/

1) Do you think these servomotors are enough  to bring a laptop on the quad ?
2) How many servomotor like this, I can control with the arduino ?? 13 ??
3) I would like as know the difference a servomotor and a digital servomotor ? Is it the same connection with the arduino?  
4) Pwm is for dc motor ?

Promise, I sent you some pictures of the quad when is finished...
38  Forum 2005-2010 (read only) / Workshops / Workshop in Toulouse in France 19-20 September on: August 24, 2009, 04:21:26 pm
http://www.artilect.fr/index.php?page=ateliers.php&id=53
39  Forum 2005-2010 (read only) / Workshops / Workshop in Toulouse in France on: July 17, 2009, 08:05:06 pm
Workshop in Toulouse in France in september
http://www.artilect.fr/index.php?page=ateliers.php&id=53

Registration here :
http://www.artilect.fr/index.php?page=sondage.php
40  Forum 2005-2010 (read only) / Workshops / workshop in Toulouse in France on: April 22, 2009, 12:52:30 am
We organize workshops (10h) during this year in Toulouse. For more informations you can visit our website
http://www.artilect.fr/index.php?page=ateliers.php&id=53
41  Forum 2005-2010 (read only) / Exhibition / Re: Arduino Pong on: March 25, 2008, 07:17:22 am
Very great work !!

May be it is a stupid question, but it is difficult to do the same thing in color or this is not possible with the artuino ? What is missing to do it ??
42  Forum 2005-2010 (read only) / Exhibition / Re: Roving robot on: February 25, 2009, 05:10:25 am
You'r right I don't spend time 20ms to wait but I spend between 1-2ms for pulses.

With 8 servos, this means I spend between 8-16ms for pulses every 20ms. So I still have between 55%-71% to execute my code and not 20% (if my operations are correct). It is not so bad. It was enough to control my robot with sensors.

(1000ms/(20ms+16ms)*20ms=555ms)
(1000ms/(20ms+8ms)*20ms=714ms)
43  Forum 2005-2010 (read only) / Exhibition / Re: Roving robot on: February 25, 2009, 04:39:03 am
I agree with you. I dont spend time to wait the servos, there is the source code here :
http://www.irit.fr/~Nicolas.Lassabe/controller_robot.pde

It's not so difficult to write your own controller to do that without to have a library.
44  Forum 2005-2010 (read only) / Exhibition / Re: Roving robot on: February 25, 2009, 02:59:49 am
You can control 12 servo motors with digital pins without motor controller.

On this projets I controle  5 servos :
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1209542023/5#5

45  Forum 2005-2010 (read only) / Exhibition / Re: Roving robot on: February 23, 2009, 01:17:42 am
Go on this page there is a code source for a robot.
 
http://www.irit.fr/~Nicolas.Lassabe/robot.php
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