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ArcticMyst Security by Avery

Troubles with HDD Galvos =/

S

Sourcegeek

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Hi, i got two hard drives 2 days ago, I connected them arm to the PC but didn't worked. Then i was trying again with the loudspeaker of a home teather, but didn't worked... Then i tried with the subwoofer of the home teather and it worked, but only with the basses =/

What i can do to amplify the PC sound and connect the hard drives? Any ideas? Yep, i tried software but is too weak =/

Thanks for all :)
 





S

Sourcegeek

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Oh thanks!
I have another question... A transistor or operational amplifier will work with a 4.5V source? Thanks

PD; I watched this video that shows two hard drives reacting to the high frequencies, i think is using a big amp :p
 
HIMNL9

HIMNL9

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Yes, there are op-amps that will work with also only 3V, and a transistor will work with any voltage over VCE, depending from the structure of the transistor and the schematic that you use.

But a normal op-amp will not have enough current for move those coils, and with transistors, you need to design a specific circuit for your needs ..... those units that i have linked, have the advantage that they are "ready-to-use", but ofcourse you can design any type of circuit you want, both transistors only or transistors drived from op-amps.
 
S

Sourcegeek

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I got temporally two transistors and all its nice, but, i have another trouble..
When i put the two hard drives in the classic stepper motors position, the arm goes down and doesn't moves correctly, the moving is limited =/
How i can fix it? Thanks
 
HIMNL9

HIMNL9

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Are you using a class-A PWM configuration, or just powering the coils and using a spring for keep the arms in the middle position ?
 
S

Sourcegeek

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I weld two cables to the top of the arm, then i just tried to pull the cables and force the arm to stay at the center, but i didn't worked because the movement is limited =/
 
Leodahsan

Leodahsan

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The amplifiers from DX are CRAP for audio output.. THD goes as high as 20% IMO... :(

They don't heat at all, the only PRO.
 
HIMNL9

HIMNL9

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^ yes, they are not for professional use, maybe good enough for PA, but few other ..... but they remain a discretely cheap solution for motor or servo driving, if not other :p :D
 
D

dasraiser

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quote: Sourcegeek
"I weld two cables to the top of the arm, then i just tried to pull the cables and force the arm to stay at the center, but i didn't worked because the movement is limited =/ "

i was pondering the same thing with the hdd arm voice coil, would adding a high frequency modulation to the input (oscillating the arm with small amplitude) help fix its position or at least stabilize it in the magnetic field? and on a side note, would dc offsetting this change its position!??!?

also Soucegeek if you didnt know the hdd platter contains a feed back track that constantly sends back position info via the pick up head so the driver knows where its located.
 
HIMNL9

HIMNL9

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You can try with an H bridge configuration driven from a PWM source ..... and changing the PWM duty-cycle for move the coil.
 
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