DVD-RW (Liteon) teardown stuff details (motors,laser diodes IR & red visual,etc)

[eneuro]

Hello,
I've made teardown of DVD-RW (Liteon) to reuse a few components in another project and trying to findout more details about stuff like this


Its laser optics probably will be very usefull in custom encoder since it has decent (huge) magnification when combined with second lens


Of course we can find in DVD-RW red laser diode


IR laser diode (invisible be very carefull with those DVD-RW laser diodes) is available too-maybe it could be usefull as light source in this encoder, but of course a lot of attention should be made and ensure to make its output very low power...


Not sure which laser diode is used as lightscriber to groove DVD/CD marks? 
Update: I've found exellent teardown of those laser diodes there Powerful laser diodes from DVD-RW drive

In the mechanic you can find two laser diode capable of burning the items. One is infrared (CD burner) and one red (DVD burner). Both diodes have about the same order of magnitude performance and thermal effects (maybe the infra burn a little more). Light from the infrared (IR) one is almost invisible (and therefore very dangerous !!!).

Anyway, we have quite nice 3 phase BLDC motor there with analog Hall sensors


Classic DC motor used to open DVD-RW front doors


So. we have 3 low power electric motors and optics for encoder module-looks like it can be reused in... small pick & place prototype I'm working on, since no huge motors needed to drive its axis, but a few more encoders to easy estimate overall position, so it doesn't matter for the moment what kinds of motors will be used, since control logic will be similar-bigger motors will need more power, but mechanical concept remains the same-no huge precision needed to pick & place SMD components, while final component placement will be corrected using visual camera (usb microscope) top view 

Trying to findout more details about this motor (DC I guess) which moves laser diodes and optics module, since I'd like use it with custom driver to hold USB microscope and move in Z vertical axis:


More detailed view below-it has E232171 markings and 10 Ohm resistance between right two pins, but it looks like there is no pure resistance between another two left pins 

What can be purpose of those two left pins in this motor?

[amyk]

That head motor is a bipolar stepper, similar to the type found on floppy drives.

[eneuro]

Thanks, it is nice to know that this laser diodes & optics holder motor it is some kind of stepper -I should be easier to control its position, since it is difficult to add there decent resolution optical encoder 
But there is no pure resistance between those two left motor connectors and those another two (10 Ohm)?
Update: OK, maybe those left two pins were well insulated or battery going dead in multimeter and missed that those left two pins should be another pair of windings of the bipolar stepper motor 

I've spare ULN2803, so will try build something to drive this bipolar motor too 
Driving a Bipolar Stepper Motor with Arduino and ULN2803AG

Another interesting usage of those DVD bipolar steppers there DIY BioPrinter  

This particular stepper motor does 20 steps per revolution (not great, but good enough), and the lead screw has a pitch of 3mm per revolution. Therefore, each step of the stepper equals a 150 micron displacement of the laser head - not bad!

Looks like they have similar parameters? 10 Ohm phase coil resistance, 5V, 20 steps per rotation 
Sample datasheet: http://robocup.idi.ntnu.no/wiki/images/c/c6/PL15S020.pdf

Holly crap! They are used in small CNC plotter and it works 

Micro Mini CNC Plotter - Part 1 - XY Using DVD Steppers


Micro Mini CNC Plotter - Part 2 - Testing Hardware and Software


I do not know why those Youtube links doesn't work under my Firefox? 

Wow, really nice tiny bipolar steppers from crappy DVDs, etc