# linear input to control a rotating servo?

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.

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6 years ago
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.
explosive_bagels (author)  rickharris6 years ago
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?
iceng6 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
AntMan2326 years ago
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.
explosive_bagels (author)  AntMan2326 years ago
3 inputs as in 3 options for input to execute. turning clockwise, stationary (neutral), and turning counterclockwise.
6 years ago
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.
6 years ago
Picaxe has servo commands built into the system.
rickharris6 years ago
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.