Use An Old DVD/CD Mechanical Part as Stacking Rail

mjkzz · Post by **mjkzz** » Mon Nov 11, 2019 12:05 am

Well, sick of robots and automation, but maybe this can help some people.

Video

Sorry (also disclaimer), did not mean to show off my stuff, but you do need a good controller able to do micro-stepping, adjustable current control, and setting pitch, steps/turn stuff to be able to use this. I believe Stackshot controller can do the trick, too, though I do not have that controller, I have heard enough to guess.

The key part is to keep the rail in the assembly, do not disassemble it. Having it in the same assembly makes it very stable, very little wobbling. Keep current under 0.625A, I set it to 0.5A (as shown in video), else the motor starts heating up. At 1/8th micro step, it can do 18.75um well, so it is suitable for 5X magnification and under. Pitch is 3mm and steps per rev is 20 (ie, it is an 18 degree motor).

Miljenko · Post by **Miljenko** » Mon Nov 11, 2019 12:36 am

Controller looks very familiar

That's a part of the whole setup I can certainly recommend!

Best,
Miljenko

gpmatthews · Post by **gpmatthews** » Mon Nov 11, 2019 4:43 am

..and a manual version from some time ago
https://www.photomacrography.net/forum/ ... hp?t=21188

mjkzz · Post by **mjkzz** » Mon Nov 11, 2019 10:11 pm

@Miljenko : OK, since you have similar controller, AND if you want to, give the CD/DVD rail a try, you will be surprised.

@gpmatthews : I am pretty sure I am not the first, but I wish those pioneers could have given it a run -- build a nice UI and make it flexible. This Cd/DVD rail is really something. I was trying to build a laser engraver with it, and it ringed a bell. I had a bad build about two years ago Here is that build video. The mistake was I took it apart. Keep it intact is the key this time around.

Macro_Cosmos · Post by **Macro_Cosmos** » Tue Nov 12, 2019 2:59 am

That manual one features a pretty cool specimen holder too!

mjkzz · Post by **mjkzz** » Wed Nov 13, 2019 4:53 pm

Here is an idea, maybe food for thought:

We all know CD/DVD tracks are very, very narrow, in microns, or even sub-microns (somebody google it please). It is obvious the 18 degree motor would not cut it to position the read head so precisely. If you notice in my video when I applied hot glue onto the read head assembly, the laser diode actually moved. Yes, it is suspended on some kind of coil structure and there is a small magnet in that assembly. This implies some kind of linear motor (or voice coil) is used to further position the head so that it can read individual tracks of CD/DVD

So I will leave it to this community to hack that thing to be able to control the head assembly. I would start to look at voice coil circuitry.

What does this mean? It means we could have a CHEAP rail with 30+mm travel with sub-micron capability. I am burnt out at work to hack it, but I might do it myself when I am too bored. But I believe collectively, this could be a good project for the community.

mjkzz · Post by **mjkzz** » Wed Nov 13, 2019 10:44 pm

Could not resist the temptation, yup, it worked as I thought. Here is a video about how I hacked it

Unfortunately, I could not find my voice coil controller, looks like I have to have some built for me, will be back in a couple of weeks.

mjkzz · Post by **mjkzz** » Thu Nov 14, 2019 10:36 pm

Another idea for these CD/DVD parts . . .It ain't bad as a XY table for stack and stitch, judging from engraving quality!

BugEZ · Post by **BugEZ** » Tue Nov 26, 2019 7:11 pm

Nice!

I have used a repurposed DVD optical head drive mechanism since 2011 or so for all of my stacks. For my small bug subjects it has plenty of muscle.

https://www.photomacrography.net/forum/ ... hlight=rig

I got about a dozen cd/dvd drives from a computer recycler for free. I disassembled them and selected a mechanism I could easily hack. I replaced the onboard stepper with a small ebay stepper and inserted a reduction pulley system (rubber band belts) that produces small accurate steps. It worked so well that I have continued to use it happily for 8 years. With my 10X objective I use 4 steps per exposure. 2 steps with my 20x objective (similar NA. I have to replace the rubber bands every two years or so. The rubber bands that the paper carrier uses work fine.

You were able to use the original motor! Impressive!

Keith

mjkzz · Post by **mjkzz** » Wed Nov 27, 2019 9:19 pm

BugEZ wrote:Nice!

I have used a repurposed DVD optical head drive mechanism since 2011 or so for all of my stacks. For my small bug subjects it has plenty of muscle.

https://www.photomacrography.net/forum/ ... hlight=rig

I got about a dozen cd/dvd drives from a computer recycler for free. I disassembled them and selected a mechanism I could easily hack. I replaced the onboard stepper with a small ebay stepper and inserted a reduction pulley system (rubber band belts) that produces small accurate steps. It worked so well that I have continued to use it happily for 8 years. With my 10X objective I use 4 steps per exposure. 2 steps with my 20x objective (similar NA. I have to replace the rubber bands every two years or so. The rubber bands that the paper carrier uses work fine.

You were able to use the original motor! Impressive!

Keith

Thanks.

Had I known your post earlier, I would not have done that Kickstarter project and just go with your setup. This CD/DVD "idea" emerged when I tried to do a laser engraver.

Yeah, with original motor, I can only do about 18.75um reliablely, with finer steps, I see some "missed"/"skipped" steps, this is probably due to the cheap motor itself.