I am using Basic Stamp 2 microcontroller with the PBasic language.
Does anyone know how to find the extreme position (i.e., 0 degree and 180 degree) of a standard servo motor?
Is there a formula in doing so?
I have both Parallax and GWservo standard servo.
I went to Parallax website and found the document ‘What’s a controller - Chap 4: Controlling motion’ which describes the pulses that make the servo rotates, however, the pulses only rotates between 2 o’clock (1ms), 10 o’clock(2ms), and 12 o’clock(1.5ms).
I changed the pulses from (1ms) to (0.8ms), and from (2ms) to (2.2ms), and that has further the range. But i need a formula that can find a prefered position.
Also, would it be harmful to the servos for the pulses that i have used (that i modified) and is it recommended to position it at its extreme (i.e., 0 and 180 degree) ?
Do i really need to make guess in order to find the position/range of the stepper motor? What is the normal range that won’t harm a servo?
Usually, the datasheets of each individual servo will list their maximum and minimum pulse.
But, I can’t say that’ll be the case, since these sorts of things vary widely between manufacturers.
For the Parallax servo, at least, I’m sure you could ask around on their forums and find someone who’s already figured it out.
I wanted to revisit this question, I was a bit short before. Every servo I am aware of uses a potentiometer for the feedbacl of the position. This is why no two servos are likely to be the same. There is no formula for this because to be honest the pot in a servo is not perfect. They try to make them linear across the entire range, but it is just not possible. So to know the min and max positions you must send the pulses and measure the results. I’m sure a simple basic program can be written to move it, and display the values.
Nick, as far as data sheets for servos go. I’m not aware of any manufacturer providing anything usable. Even the Hitec datasheet, whick is not servo specific, only states the pulse range is .9 to 2.1mS. They are only interested in stating what is important for the RC airplane, car, or boat user needs to know. They don’t want to address the issue of getting a full 180° range for example. Now a reseller may publish a data sheet, but not the manufacturer.
