Three servo tester with potentiometers

[Deimos]

You can prove your servos with potentiometers, it shows in the lcd the current position of the servomotor.



Code in PBP for Pic micro:

DEFINE LCD_DREG PORTB
DEFINE LCD_DBIT 0
DEFINE LCD_RSREG PORTB
DEFINE LCD_RSBIT 5
DEFINE LCD_EREG PORTB
DEFINE LCD_EBIT 4

Define ADC_BITS 8
Define ADC_CLOCK 3
Define ADC_SAMPLEUS 50

adval var byte
b0 var byte
b1 var byte
b2 var byte
b6 var byte
b7 var word
mover var word

TRISA = %11111111
ADCON1 = %00000010

pause 250

lcdout $FE,1,"SRV1 SRV2 SRV3"


start:
 lcdout $FE,$C0,dec3 b0,"  ",dec3 b1,"  ",dec3 b2
    PORTC = 0
    pulsout PORTC.0, b0
    pulsout PORTC.1, b1
    pulsout PORTC.2, b2
    b7 = b0 + b1 + b2
    b6 = b7/100
    b7 = 15 - b6
    pause b7
 Adcin 0, b0
 Adcin 1, b1
 Adcin 2, b2
    goto start
end

I think it is useful to study the positions of the servos to make a simple robot.

I hope that simple example will be useful.

Enjoy 

[Deimos]

Here's a video of this project, im usin three hitec HS-311 servos:

http://www.youtube.com/watch?v=DRM2oxue3Dc

[frasenci]

nice video !

would you show in detail how you made the opening/closing clamp ??

greetings

[Deimos]

you can buy the grip here:

www.lynxmotion.com

here is an image:

[robban]

What kind of servos are You using? The normal servo signal is a 2 ms spike and 20 ms period...

[frasenci]

What kind of servos are You using? The normal servo signal is a 2 ms spike and 20 ms period...

Good point robban.

Maybe , deimos forgot an important step in his/her code wich is the scaling of the value obtained from ADC , to fit standard pulse length used by RC servos like the one shown on foto.

For info , a standard RC servo like Hitec , Futaba will use :

Far left : pulse length  = 1000 ms
Center   :                  = 1500 ms
Far right :                  = 2000 ms

by all means , pulses must be fed into servo electronics at least every 20 ms ( 50 hz ) . Otherwise , servos willl shutter

my 10 cents

greetings
 

[robban]

That's correct Fracenci. Myself, I use a PWM(sort-of)-signal so I can gain full control from the RC-control:
' Program to move RC servo using potentiometer(Proton)


//for the 16f628 or whatever; the smaller the better and don't forget to use as low freq as possible for battery longevity

' Define ADIN parameters
      ADIN_RES = 10         ' Set number of bits in result
      ADIN_TAD = FRC         ' Set clock source (3=rc)
      ADIN_STIME = 100                   ' Set sampling time in uS

      Pos     Var     Word      ' Servo position
      Symbol Pin = PORTB.3      ' Alias servo pin


      Input TRISA         ' Set PORTA to all input
      TRISB = %11110000      ' Set PORTB.0-3 to output
      PORTB = 0         ' Set PORTB.0-3 low
           ADCON1 = %10000010                   ' Set PORTA analog and right justify result


' Main program loop

   loop:
   Pos = Adin 0         ' Store value of analog input in pos
        Servo Pin , 1500 + Pos                          ' start with center
        Delayms 20            ' Servo update rate
        Goto loop            ' Do it all forever

        End

[Deimos]

I'm using HS-311 servos.