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can anyone teach me servo 101 simply?


i want to do a pan/tilt head to put a light on top (probably leds)

ive read on the internet that servos are controlled via pwm, is there any simpler ways to controll it with a potentiometer?
i can build this circuit no problems, its just to know

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AndyGadget5 years ago
 
A servo isn't just a simple motor, there's also control circuitry in there which requires the pulse to set the arm position.  A pulse of 1.5mS will give you approximately mid position, and from 1mS to 2mS will give you the full range of travel on most servos.  The pulse needs to be repeated every 20mS or so.

Read through PART1 of an excellent tutorial which details the mechanics, electronics and operation of the servo, and then PART2 which tells you how they can be modified in various ways.

What sort of camera are you making the pan / tilt head for?
Is it compact or SLR.  For a SLR you're going to need heftier servos and have it well balanced. Give us more details and I'll tell you which servo to use.
rickharris5 years ago
Assuming you have a standard analogue servo then it is controlled by a variable WIDTH pulse. In your servo tester this is provided by the 555 times IC.

You should be able to use that circuit for your pan and tilt head.

A more modern take on servos is a digital servo which receives number rather than pulses - these numbers are converted into position information.

Inside the analogue servo a small variable resistor is turned as the motor turns, this resistor does exactly what your 555 know does it a alters the width of a pulse generated inside the servo. When this internal pulse is the same size as your supplied demand pulse the servo stops moving.
pbergeronronronron (author)  rickharris5 years ago
i dont have any servo's yet, can you recommend one in any of theese? http://s.dealextreme.com/search/servo
Get a standard servo that suits your budget - even if later after more experience you end up changing it.
Any of the servos there should be good, but you don't want the micro or mini servos. They have very little torque and break easily.