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linear input to control a rotating servo? Answered

Im trying to build a circuit in which an input uses linear motion to control a rotating servo. the servo rotates clockwise/counterclockwise, and the input should have 3 inputs. turning the servo clockwise, turning the servo counterclockwise, and a neutral option so the servo doesn't have to always move; the neutral would be between the to rotation inputs. The closest form of an input I've found so far is a sliding potentiometer since it is controlled by linear motion. If there's a better input that can have those 3 inputs i'd love to know.


Changing liner at rotary motion is usually done mechanically with a rack and pinion although a string wrapped round the shaft of a POT would also do it.

Your normal servo controller produces a variable width square wave at a repetition freq suitable for the servo - These are well documented on the web.

A simple 555 times servo controller should do it for you. The linear pot is a good solution .   Here for example

When the pot is stationary the servo controller continues to send the pulse train but with no change so the servo doesn't move.

sweet. I'm still pretty new to circuitry so pardon any ambiguous references i made. would you happen to know of any good intro/beginner guides or sites for integrating POT into my circuit?


6 years ago

LVDT = Linear Variable Differential Transformer.
To improve your repertoire of sensors and maybe raise awareness of
clicking the best answer this year.
I would use the ratio voltages to modulate the driving servo frequency
sq wave by using that as the lvdt source input .  .  .  .  .  .   A


I'm not sure I totally understand the question, the bit about the input having 3 inputs? I know, however, that a linear pot would work well, either with a 555 as suggested below, or probably more simply, with a microcontroller such as an arduino to turn the input into Servo movement.

3 inputs as in 3 options for input to execute. turning clockwise, stationary (neutral), and turning counterclockwise.

You should look up how a servo works, how RC receivers drive the servo and how a servo driver works then you will better understand what you are trying to do.

Picaxe has servo commands built into the system.

POT stands for Potentiometer A variable resistor (of sorts)

The rotating resistor in any of the circuits can be replaced by a linear resistor.

There are 3 connections each end of the resistive strip and the wiper that connects to the strip and moves to change the resistance. make sure you connect the right ones up.