RoboStar SBRS-5314HTG 280° and Arduino

Other Hardware Motors, Mechanics, Power and CNC
1

Hi guys,

I'm going to buy a RoboStar SBRS-5314HTG 280° since, for a project, I was using an Hitec 805BB servo but I've a serious lack of torque.
Guys at HobbyKing suggested me the Robostar, but I'm tempted to use a JX PDI-HV2060MG

basically I need to move an heavy object of + - 10° from the center position, this is my code:

#include <Servo.h>

const int servo1 = 9;       //  servo
const int joyH = A0;        // Joystick

int servoVal;           // variable to read the value from the analog pin


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

int servoVal1 = 90;
int servo1last =90;



void setup() {

  // Servo  
  myservo1.attach(servo1);  // attaches the servo
  

  // Inizialize Serial
  Serial.begin(115200);
  myservo1.write(servoVal1);
  
}


void loop(){


    // Read the horizontal joystick value  (value between 0 and 1023)
    servoVal = analogRead(joyH);          
    if (servoVal > 1000){
      servoVal1++; } 
    else if (servoVal < 200){
      servoVal1--; } 
    
servoVal1 = constrain(servoVal1, 80, 100);
      
if(servoVal1 != servo1last) {
  myservo1.write(servoVal1);
   delay(20);   
 servo1last = servoVal1;
}  else  {
 myservo1.write(servo1last);
   delay(20);   
   }

I noticed that Robostar is not a classic 0-180° servo, so if I'll buy it, how do I have to modify my code to make it work properly?

Any other cheap servo with more torque than the 27Kg of the Hitec 805BB?

Thanks

2

I think the only thing you need to know is that servo.write(180) will make that servo move to 280 degrees. You will probably find it less confusing to use servo.writeMicroseconds()

...R

3

Hi Robin,

I guess there's a difference between library's microseconds and motor's microseconds.
The biggest problem is that, as you can read, I move my servo one degree at time.
So, since my specific application needs to move from 80° to 100°, with a 0 point to 90° (I'll never ever reach 0° or 180°), Can I continue to use my sketch and the motor will operate correctly or do I have to ridefine the microseconds?

If yes, which is the best way to do this?

Otherwhise is there a 0-180° servo which is not so expensive and has a enough torque?

Did you find more "solid" the RoboStar SBRS-5314HTG 280° or the JX PDI-HV2060MG ?

Thanks

4

adepalo:
So, since my specific application needs to move from 80° to 100°, with a 0 point to 90° (I'll never ever reach 0° or 180°), Can I continue to use my sketch and the motor will operate correctly or do I have to ridefine the microseconds?

You will need to experiment to find the command values that make the new servo go to 80 and to 100 deg and then interpolate between those values.

Using writeMicroseconds() will give you finer control.

I have no knowledge of expensive or powerful servos. The cheap HobbyKing £3 servos meet my needs.

...R

5

Be aware these large servos need many amps, perhaps 4 to 8A.

What is the application? is a servo the best solution? Would a linear actuator be better?
What positioning accuracy do you need (servos are usually not great).

basically I need to move an heavy object of + - 10° from the center position

"Heavy" is not a number, and details matter for mechanics calculation. Have you calculated
or measured the actual torque needed? Guesswork can be expensive, best to be sure.

6

Hello,

This is the setup.
The object is balanced.
I have to move the servo to tilt it + or - 10 degrees, one degree at time. basically it's like an old weighing scale and two arms.

Now, my physics is a little bit old ... but since W * L = W * L do I have to worry about overall weight?

setup.jpg