ATTiny85 and servo's

[Benjamin Crowe]

Hello,

I am currently trying to shrink an Arduino project I am currently working on by using a ATTiny85 and I am running into issues with the servo I am trying to attach to it, would anyone be able to lend a hand working this out? I am using the SoftwareServo library, though every time I upload the sketch to the ATTiny it throws up a error saying it is out of sync.

Any ideas or suggestions would be great.

Thanks

Ben

[jfowkes]

If your program complies but doesn't upload, the problem isn't with your code or the servo library.

What are you using the program the ATTINY? What is the precise error message you're getting?

[Benjamin Crowe]

I am using an Arduino Uno in ISP mode to program the ATTINY, I decided to go back to using IDE 1.0.0 which seems to upload fine now, must of missed something out last night whilst tired, though the main issue I have now is that the servo won't rotate a full 180 degrees of motion, it seems to get stuck at one of the extremes then just pulses. Here is the code I am using:-

#include <SoftwareServo.h> 

SoftwareServo myservo;   

void setup() 

{ 

  myservo.attach(0);  

} 

void loop() 

{ 

 

  myservo.write(10);   

 SoftwareServo::refresh();   

  delay(1000);                          

 

myservo.write(179);       

 SoftwareServo::refresh();

  delay(1000);                           

} 

Any help on this would be appreciated.

Ben

On 27 March 2014 07:15, jfowkes <james...@gmail.com> wrote:

If your program complies but doesn't upload, the problem isn't with your code or the servo library.

What are you using the program the ATTINY? What is the precise error message you're getting?

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[jfowkes]

If you read the introduction to the SoftwareServo page (http://playground.arduino.cc/ComponentLib/Servo#.UzPrz_l_utY), you'll see the following:

"you must call the SoftwareServo::refresh() method at least once every 50ms or so to keep your servos updating."

Can you see where the problem lies?

[Benjamin Crowe]

#include <SoftwareServo.h> 

SoftwareServo myservo;   

void setup() 

{ 

  myservo.attach(0);  

} 

void loop() 

{ 

 

  myservo.write(10);   

 SoftwareServo::refresh();   

  delay(1000);                          

 

myservo.write(179);       

 SoftwareServo::refresh();

  delay(1000);                           

SoftwareServo::refresh(50); //I take it this is the problem I had I wasn't refreshing the servo so, is that the reason why it was getting stuck??

} 

[jfowkes]

Not quite. The refresh method doesn't need to be given a number. But look at how long you are delay()ing for between refreshes...

[Chris ((drazziweht)) Cain]

>Any help on this would be appreciated

Try this....

 #include <SoftwareServo.h> 

SoftwareServo myservo;   

int loopcount ;

void setup() 

 {

    myservo.attach(0);  

     loopcount = 0;

 } 

 

void loop() 

 {  

  switch(loopcount) {

     case 1:

             myservo.write(10);

     break ;

     case 50:  // 1 second (50 * 20 msec)

             myservo.write(179);

     break ;

   case 100:   // 2 seconds

           loopcount = 0;

    break ;

   }

 loopcount++ ;

 SoftwareServo::refresh();

 // loop every 20ms

 delay(20) ;

} 

[Benjamin Crowe]

Thanks Chris I will give it a go.

[jfowkes]

If you just copy-and-paste Chris's code, make you you understand what it does and why it works!

Little point using an answer without understanding it.