In need of assistance please

Question

Hello - Tony here, and I am a totally new person to the whole arduino world. First my project, my equipment, why I decided to use arduino, what I am attemting to do, a Fritzing diagram, the code I am using, and a Fritzing diagram (jpg format). My project is relatively simple; the ability to pan and tilt 2 cameras that weight .06 ounce. The cameras are being used to record the weather. The programming below works, but the problem I am having is that the servos return to the zero (or do we call it the 90° location) when I release the joystick. The joysticks I am using are the same type used in the Playstation 2 game pads. They allow for a Z axis which for me, I would like to use as a way to keep a camera pointed in the direction I last positioned it to, until the time I wish to pan or tilt it to a different axis. I hope I explained it clearly. Lastly I do not want to use wireless, I wish to have it hard wired as I believe it will cause less interference by other radio frequencies in my area. My equipment or components are as follows: Arduino UNO board Bread board Circuit board 2 Joysticks (Playstation 2 style with X, Y and Z axis) 4 TowerPro servo motors SG5010 I decided to use arduino, because it was recommended to me by computer / electronic shop personnel. I have no prior knowledge of coding arduino or any other type of programming. I was however able to take coding for 1 joystick and 2 servos, and expand it to include an additional joystick and 2 additional servos. So as stated, I have coding for 4 servos and 2 joysticks, I just cannot and do not understand what I need to do in order to get the Z axis enabled to do what I stated above. I have included the Fritzing diagram in jpg format so that it may be easier to understand what I have going on. I apologize to those that are more experienced, that I bring this here, but I really am in need of assistance. The coding: #include <Servo.h> const int servo1 = 3; // first servo const int servo2 = 11; // second servo const int servo3 = 6; // third servo const int servo4 = 10; // fourth servo const int joyH = 3; // L/R Parallax Thumbstick const int joyV = 4; // U/D Parallax Thumbstick const int joyI = 1; // L/R Parallax Thumbstick const int joyW = 2; // U/D Parallax Thumbstick int servoVal; // variable to read the value from the analog pin Servo myservo1; // create servo object to control a servo Servo myservo2; // create servo object to control a servo Servo myservo3; // create servo object to control a servo Servo myservo4; // create servo object to control a servo void setup() { // Servo myservo1.attach(servo1); // attaches the servo myservo2.attach(servo2); // attaches the servo myservo3.attach(servo3); // attaches the servo myservo4.attach(servo4); // attaches the servo // Inizialize Serial Serial.begin(9600); } void loop(){ // Display Joystick values using the serial monitor outputJoystick(); // Read the horizontal joystick value (value between 0 and 1023) servoVal = analogRead(joyH); servoVal = map(servoVal, 0, 1023, 0, 179); // scale it to use it with the servo (result between 0 and 179 to keep from being jittery) myservo2.write(servoVal); // sets the servo position according to the scaled value // Read the horizontal joystick value (value between 0 and 1023) servoVal = analogRead(joyV); servoVal = map(servoVal, 0, 1023, 0, 179); // scale it to use it with the servo (result between 0 and 179 to keep from being jittery) myservo4.write(servoVal); // sets the servo position according to the scaled value // Read the horizontal joystick value (value between 0 and 1023) servoVal = analogRead(joyI); servoVal = map(servoVal, 0, 1023, 0, 179); // scale it to use it with the servo (result between 0 and 179 to keep from being jittery) myservo1.write(servoVal); // sets the servo position according to the scaled value // Read the horizontal joystick value (value between 0 and 1023) servoVal = analogRead(joyW); servoVal = map(servoVal, 0, 1023, 0, 179); // scale it to use it with the servo (result between 0 and 179 to keep from being jittery) myservo3.write(servoVal); // sets the servo position according to the scaled value delay(15); // waits for the servo to get there } /** * Display joystick values */ void outputJoystick(){ Serial.print(analogRead(joyH)); Serial.print ("---"); Serial.print(analogRead(joyV)); Serial.println ("----------------"); Serial.print(analogRead(joyI)); Serial.print ("---"); Serial.print(analogRead(joyW)); Serial.println ("----------------"); } Thanks for taking the time to help me. I do appreciate it. Tony 
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cookieglitch · Answer

If I'm reading this correctly, the problem you are having is that the servos jump back to zero (or 90 or the start position or the default position, whatever you wish to call it.) when you release the joystick. This is a fairly simple problem in the code and rather easy to fix. With any problem like this, let's make it as simple as possible and work from there (Fewer parts can after all be a bit less of a headache). We can start out with one axis and one servo. Currently in your program, whenever you read from the joystick, you are moving the servo. To avoid the problem you are having, you need a way to remember where the servo should be, check if you do need to move (i.e. not at the start position on the joystick) and handle the change from there. To do this, you will need a variable to hold the current position, and another to hold the new reading from the joystick. You can then check the conditions of these, such as if they match, using an if statement. One way to make the solution simpler while you start out is to interpret zero as "do not move" rather than a position and to instead use a button (such as depressing the joystick) to mean "return to start position". This may require additional buttons as you start introducing the other axis, but that is a concern for later. To some extent, you need to understand how the joysticks work. Inside the stick is a potentiometer, setup in a way that means the start position (zero) is actually a value such as 5k ohms (This will vary depending on the part, refer to the datasheet or measure it with your multimeter). When this is read by your arduino, it will be around 512 (Extreme left being zero, extreme right being 1024, you will need to check those). One way your program could work is to look at the value, if it is not "zero" and is different to the current value, move to it. If it is "zero", or the same as the current value, do nothing. This would look something like the code below. This is by no means the best solution, and may not work exactly as it should, it may however give you an idea of what you are aiming for. This example will produce a lot of jitter when you run it and the reset button requires debouncing for it to work correctly. #include <Servo.h>

const int cam1panPin = 3; //Cam 1, Pan servo pin

const int joyH = 3; // L/R Parallax Thumbstick Pin

Servo cam1pan; // create servo object to control a servo

int c1Pan_OldVal = 512; //Old value for comparison

int c1Pan_Pos = 512; //Current position

int resetButtonPin = 5;

void setup()
{
 // Servo 
 cam1pan.attach(cam1panPin); // attaches the servo
 
 // initialize the pushbutton pin as an input:
 pinMode(resetButtonPin, INPUT);

// Inizialize Serial
 Serial.begin(9600);
}

void loop()
{
 // Display Joystick values using the serial monitor
 outputJoystick();

int c1Pan_temp = analogRead(joyH);
 
 if(c1Pan_temp == 512) //If in start position. May need to be a range of values
 {
 //Do nothing
 }
 else if(c1Pan_temp != c1Pan_OldVal)
 {
 //If different to old value, move
 c1Pan_Pos = map(c1Pan_temp, 0, 1023, 0, 179);
 cam1pan.write(c1Pan_Pos);
 
 //Save current reading as old
 c1Pan_OldVal = c1Pan_temp;
 }
 
 //Read reset button
 //Requires debouncing
 int buttonState = 0;
 
 //If button is pressed, go back to middle
 buttonState = digitalRead(resetButtonPin);
 if(buttonState = HIGH)
 {
 c1Pan_Pos = map(512, 0, 1023, 0, 179);
 cam1pan.write(c1Pan_Pos);
 
 //Save current reading as old
 c1Pan_OldVal = 512;
 }
 else
 {
 //Do nothing
 }

delay(15); // waits for the servo to get there
}

/**
 * 
 * Display joystick values
 * 
 */

void outputJoystick()
{
 Serial.print(analogRead(joyH));
 Serial.print ("---");
} The short (and probably much less confusing) version of this is that you need to look into using if statements, and use them to make sure the position only changes when you want it to. With any luck this should help you solve your problem!

billabott · Answer

Hello Tony.

I am not sure, but isn't the z-axis on the ps2 controller an integrated switch that closes when the joy stick control is pressed in? What do you want to use it for?

RE the fritzing pic: why is there an extra wire going up to the left of the joy stick?

Okay, so we are all on the same page: After the itty bitty "weather" cam is mounted pointing to the center of the field of view, imagine a sheet of graph paper placed in front of it with the Origin (0,0) in the middle of the page and in line with the center axis of the "weather" cam. Both servos would be at 90 degrees to allow a panning movement to the left and right and also to allow a tilt movement up and down.

To make your sketch a little easier to follow, understand, and maintain; I want to suggest the following changes.

Instead of

Servo myservo1; // create servo object to control a servo

Servo myservo2; // create servo object to control a servo

Servo myservo3; // create servo object to control a servo

Servo myservo4; // create servo object to control a servo

you could use

Servo cam1pan; // create object to control cam1 panning (x-axis)

Servo cam1tilt; // create object to control cam1 tilt (y-axis)

Servo cam2pan; // create object to control cam2 panning (x-axis)

Servo cam2tilt; // create object to control cam2 tilt (y-axis)

-Billabott, aka Viewer44

In need of assistance please

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