I have looked up for this but I can only find old posts.
I have hooked up a 7200rpm Hard drive disk that I have removed all the circuitry and arm, and only left one plate and the motor.
The motor have 4 wires ( 3 poles and commond groud).
I have surfed the web a lot and found a topic (http://letsmakerobots.com/node/2876) of someone who was able to drive a hdd with a couple of pics.
Well I have followed the circuit with a couple of L293 in a Piggyback setup ( that I have learned also this days) and connected to my adjustable powes supply.
I have mounted a CNY70 optical infrared sensor under the plate and put a black tape in a side of the plate to detect every count in order to feedback the necessary pulse to drive the motor
I have worked for some days and I have sucefully driven the motor to up to 4600rpms, I didn't try to go far as It´s not my intention to reach max speed.
What I am trying to do is to make one of those hdd POV clocks like in this LED Hard Drive Clock 3.5".
Now I have a couple of questions that maybe someone could answer.
As the resistance between the coils of the Hard drive is 1 or 2 R, the motor try to take as much current as It can. I am limiting the current with the Lab dc power supply to 1,2 Amp, but the disk is supposed to work with only 0,7 Amps. If I don't limit the current, the sistem try to get as much current as possible rising up to the limit of the powers uplly 3 Amps. I imagine that is due to the low resistance.
1.- Does anyone know how to avoid this with electronics(limit the current). I mean with component as I am planing to feed the sistem with a cheap DC wall power supply. ???
It is there any Hbridge or shield that can do this ?? or Is there any ciruit?
I was working hard and I needed one week only to realize the the serial comunication was the problem that didn´t allowed the disk spin above 800 rpm. Once I dissables serial com and installed the sensor for feedback with a PID I started to achieve high speeds, the arduino is able to pulse the coils, read the sensor, apply the PID and feed back so the second question is.
2.- Do you think that Arduino Uno has the needed power to to this, plus the POV stuff. I mean, drive the motor and make the leds according to the sensor to display the time ??
I have bought and R/C controler that I did not arrive yet but It has 3 wires and I am not sure that I will be able to drive the 4 wires HDD. But also IT was a lot of work for me to do this hdd drive and I would like to try to do it all with the Arduino.
Thanks a lot.