Control a Servo Motor Without Programming

By Jonathan Best
Category: Electronics
Time Required: 30 minutes
Difficulty: Moderate

I am going to guide you through the process of making a circuit that will allow you to control a servo by turning a dial. At the same time I will explain what is going on in the circuit and how it works.

Steps

Step #1:

A servo motor is controlled by sending a series of pulses to it. This is called "pulse width modulation." Depending on the length of the pulse it will turn to a specific angle.
A pulse must be sent to the servo every 20 milliseconds. The pulse length will vary from 0.5ms to 2ms. If it is 0.5ms the servo will turn as far as it can anti-clockwise. If it is 2ms it will turn as far as it can clockwise.
By using a pulse-generating circuit controlled by a potentiometer any pulse length between 0.5ms and 2.0ms can be sent to the servo. This allows us to move the servo arm to any position desired.

5 Responses to Control a Servo Motor Without Programming

Jonathan Best on November 14th, 2012 at 10:57 am said:

Hey, am very sorry I missed that out, this is the first guide I have made.

The positive lead from the battery goes to the right hand terminal where it has 0v/6v written beneath it.

Hope that helps,

John

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Jonathan Best on December 2nd, 2012 at 10:53 am said:

Not that I can definitely say. Try putting two servos in parallel on the output.
Sorry I couldn’t be of more help.

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Jonathan Best on December 3rd, 2012 at 9:10 am said:

I don’t have the file on my computer at the moment (at university and it is at home), sorry.

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Tom on January 25th, 2013 at 8:11 pm said:

Google ’555 timer servo controller pcb layout’

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David Hdez Moreno on April 29th, 2013 at 11:30 pm said:

Hi, where is the potentiometer? I need to control a servomotor that allows up to 36 V DC. Do this circuit works for it too?

How are connected the pins of the servo?

Regards

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