Electronic – arduino – hard drive head/seek motor with Arduino

arduinohard drivestepper motor

I can see there are many writings on line for using an Arduino to control a 4 or 6 wire stepper motor, that spins the platter in side an IDE hard drive. I want to control the seek read/write head motor instead, can this be done? I'm struggling to find anything at all on this?

Best Answer

As snoopen says - you want a "voice coil" driver or actuator.
It's well within the capabilities of an Arduino to drive one of these.

There are a number of people offering on-web examples of HDD voice coil drivers used for other purposes.

Wikipedia overview

This provides a general view of an HDD voice coil actuator

This is an actuator withy the magnets in position above and below the coil

and here is a unit with the magnets moved out of position to provide an internal view.

enter image description here

__________________________________________________________________

Here is an utterly amazing LASER shutter driver achieving mechanical shutter rise times of
500 nS !!!. There are a number of links off this page to other variants and upgrades.

Their basic driver circuit is suitably simple -

enter image description here

Here is a formal 2004 paper based on the above

And three years later in 2007, an updated version

Here is a throttle position control using an HDD actuator.

Circuit diagram here - the actual actuator control is the middle third hozizontally and the actual driver is 2 transistors driven by an opamp. An Arduino could easily feed a s signal to such a circuit. eg smoother PWM or a DC voltage generated in some other manner.

enter image description here

Related Solutions

Electronic – arduino – basic arduino question – do I need a 555 timer

It can be done with interrupts. Attach an interrupt to a timer, so that it fires regularly (say once a milisecond), and use that interrupt to pop the next command off the top of a queue (could just be an array).

Your main loop then just adds commands to this array.

A single Arduino has 14 IO lines, so the number of motors you can control depends solely on the number of wires needed for each motor.

There are dedicated stepper motor driver ICs that are much better and simpler than using a 555 timer. The floppy drive will be using one (maybe embedded inside another chip). They usually accept simple up/down step signals and convert them into the proper sequence of pulses.

Edit

Example code, using the Timer1 library:

#include <TimerOne.h>

void test()
{
  digitalWrite(5,HIGH);
  delayMicroseconds(100);
  digitalWrite(5,LOW);
}

void setup()
{
  Timer1.attachInterrupt(&test,100000);
}

void loop()
{
}

This will cause digital pin 5 to go high then low once every 100,000µS - you see there is nothing in the main loop at all. Just replace the two digitalWrite() calls with the code to step your motors once. You do not need to specify any inter-step delay in that part of the code - that delay is set by the value of 100000 in the Timer1.attachInterrupt() function. To change the speed of the steps, change that value.

Electronic – arduino – Help identifying a motor and how to control it with an Arduino

That's definitely a universal motor (also called a series wound motor because the stator and armature are connected in series). Unfortunately I can't help you with your second question as I don't have any experience controlling universal motors.

Best Answer

Related Solutions

Electronic – arduino – basic arduino question – do I need a 555 timer

Electronic – arduino – Help identifying a motor and how to control it with an Arduino

Related Topic