So you're 22 then?

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PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Feel like it anyway, at least until I see someone who is 22:-)

 

When i go to the shop today i'll post what code i used if i can find I made a board with a 12f675 to run the motor

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Burt
http://mybe80be.com
http://stores.shop.ebay.com/mybe80be__W0QQ_armrsZ1

 

Thanks Burt.

I'm keeping an eye on your eBay store. I'm sure you'll have some stuff that will come in handy for projects as I go along.

Frank

 

Here a picture of the board still looking for code I think the code and circuit was on my
old harddrive that went bad
What you do is set the common of the hard drive motor to + vdd and that gives you 3 wire
that you hook to Y1 Y2 Y3 set the bridge EN pin to low and switch A1 A2 A3 on and off in a row the motor will spin I used a I think 10mS delay to start the motor then after it was spining the code changed the delay to 5ms

__________________
Burt
http://mybe80be.com
http://stores.shop.ebay.com/mybe80be__W0QQ_armrsZ1

 

Wow Burt this is great I'll have to try it.
Thanks a lot for posting the circuit.
Frank

 

Hi guys,

Just though I would add my 2 cents worth. I've also played with these motors a bit. The motors I've seen also have their coils in a Y configuration with a tap in the middle. I use a different driver but otherwise my approach is very similar to that of be80be.

The problem I found is that the timing is critical. When I used fixed delays the rotation is not very robust. Sometimes it would spin up, other times not. Sometimes it would spin for a while and then lose sync and stutter to a stop.

When used in a hard drive, the magnetic information on the drive platters is used to synchronize the coil timing to the rotation. Coil transitions occur at just the right moment and the motor accelerates strongly and holds speed against all perturbations.

I made a simple optical encoder disc using a laser printer and a transparency. I used an optical interrupt switch to sense the black to transparent transitions and used this to clock the coil transition. The change was dramatic. With this feedback I could easily reach the rated speed of the motor. After slowing the platter with a finger, the motor would rapidly recover its speed.

A friend of mine, Paul Rowntree, adapted this approach for use with the propeller chip and posted the project at

Propeller Object Exchange

Hope this is helpful.

DrIguana

 

if the HD motors are BLDC then doesn't it have some hall effect sonsors, is it possible to sens the rottar via such hall effect sensors

 

Hi Hatha,

You probably know this but, the position of the spindle is "written" on the platter of hard drives. All that is gone with the removal of the platter and the read head. In the link DrIguana provided they replaced the position information with a transparent disk mounted to the spindle and a sensor for feedback.

There are chips out there that will use back EMF sensing for sensing the position of the spindle motor.

Would this chip work for that?
"Connections for TPIC43T01 and Discrete Power NMOS FETs"
http://focus.tij.co.jp/jp/lit/an/slit117/slit117.pdf

 

Hi Frankco

thank your for your interesting article yes this chip (TPIC43T01) has the ability to sens the rottar position via hall effect sensors. have to read more about this
thank you again