hello , I recently purchased a large amount of servos for use in a project where each servo would have an arm fitted that would strike a bell. I've been using this very simply sketch to check to power of of the servos
#include <Servo.h>
Servo myservo;
void setup()
{
myservo.attach(9); // attaches the servo on pin 9 to the servo object
}
void loop()
{
delay(150);
myservo.write (60);
delay (150);
myservo.write(120);
}
But Ive found that they will slowly rotate infinitely while jerking back and forth? , I just want them to be able to strike and retract ?. instead they will strike and retract while also rotating there overall position (sorry if I havn't explained this well). what is the reason for this? I do not require fully rotational servo's for this project , but they were the cheapest kind of adequate size that the vendor had in stock. is there a way round this problem?
"Full Rotation" servos have ben modified to no longer be servos. They act like a geared motor with a built-in speed controller. At angles near 90 they stop. At angles below 90 they rotate in one direction. At angles above 90 they rotate in the other direction. They are most often used for the wheels of little robots.
I'm afraid you will need to buy regular servos if you want to hit and retract.
I recently purchased a large amount of servos for use in a project where each servo would have an arm fitted that would strike a bell.
Maybe a servo is simply the wrong thing... For example, a door bell uses a [u]solenoid[/u].
Or you might want a regular 'ol DC motor, possibly with a couple of limit sensors/switches so your software can know when it's gone far enough.
A typical servo application is to control the steering on a remote control car. You specify the angle, and the motor moves to that angle. Servo motors are geared-down so they tend to be fairly slow. If you want to slow it down more, you can slowly increase/decrease the angle. If it's jerking back-and-forth, something is wrong.
A stepper motor can rotate the full 360 degrees in steps of 1.8 degrees. (Or, you can "microstep" them to move a fraction of a step). Usually, stepper motors need some sort of limit sensor to find their "starting point" Stepper motors can be fast (or slow, obviously) but usually not as fast as a DC motor. For example, the movement of a printer head is usually controlled by a stepper motor. There is a position sensor to find "home" when the printer is powered-on or reset, then the firmware just keeps track of the number of steps back-and-forth so it knows where it is on across the paper. Another stepper motor may feed the paper.
mmm looking at it a solenoid does seem a much better choice , ah well I have made my bed now I must lie in it , will definitely look into solenoids for the next time though