Microscopy Hack Chat

Ahron Wayne12:43 PM
This one?

Dan Maloney12:43 PM
I wasn't going to this time, I swear!

Patrick Hickey12:43 PM
@polyfractal greeting from scotland. I recently salvaged a biorad radiance 2100 confocal, currently trying to source a solid state laser to replace the argon ion laser, any recommendations for a 488nm module supplier?

Ahron Wayne12:44 PM
with "only" 60,000 views and 200 comments, one of whom is applied science guy? :)

polyfractal12:44 PM
yep that one @Ahron Wayne! the results weren't great, but it was a fun project and with some tweaking i think it could work.

And yeah it gained a bunch of traction in the last few months thanks to the big influx of traffic, but it was a "dud" for a very long time which can be demoralizing if you let it get to you :)

polyfractal12:45 PM
@Patrick Hickey oh nice! congrats! afraid I don't have any that come to mind, 488nm is a bit of an oddball wavelength. tbh I do most of my scavenging from ebay too so dont know many real vendors :)

Ahron Wayne12:46 PM
I'll add that one to my watch later then, and it answers my question as to whether you'll turn your attention to metal printing.

polyfractal12:46 PM
is the argon laser dead, or just don't want the hassle of big inefficient gas laser?

Ahron Wayne12:47 PM
If you're actually trying to repair/use the laser Sam's laserfaq is a great source: https://www.repairfaq.org/sam/lasersam.htm

polyfractal12:47 PM
@Ahron Wayne heh. I do have some vague plans to work on SLA + nanoparticles + sintering. not quite direct metal printing but roundabout way to get there. ditto to ceramics. Mostly boils down to small enough particles and keeping them colloidal, which usually needs some extra chemistry to work (e.g. alumina will remain suspended in resin if you add some citric acid)

Patrick Hickey12:49 PM
cool, thanks @polyfractal i found a good supplier based in poland “lambdawave” they have many flavours of lasers, arduino controllable and low prices. Hope to connect with you in future! Patrick

polyfractal12:50 PM
related to that old lattice video actually, i'm currently working on some new electroforming projects, building up a really thick deposit on 3D prints for functional reasons. we'll see if it works out for the particular project, but feels underutilized by hobbyists :)

Thomas Shaddack12:50 PM
What resin? I did some research on a now likely dead project with printing resins...

Ahron Wayne12:50 PM
@polyfractal please keep us updated on that. I've been working on bound metal printing with filament for the past few months and there's a huge amount of potential, but I'm especially excited about the idea of working with powders mixed with resin because you might be able to mix your own alloys and also get huge details. One company described SLA-metal powder as "like butter" being spread on the plate which presents its own challenges of course.

Ahron Wayne12:51 PM
@polyfractal You should definitely check out the Virtual Foundry/Bradley woods, he got started with electroforming 3D printing exactly as you're describing before he started manufacturing metal filaments.

polyfractal12:51 PM
@Thomas Shaddack just generic cheap SLA resin so far (elegoo maybe?). Haven't done much work on it yet, just enough to realize that particles either need chemical modification to stay in suspension, or some kind of agitator, or they need to be nano-sized. hit pause on it for a while to work on other projects

Ahron Wayne12:52 PM
There is also some talk in the community about debinding ceramics and other materials and then infiltrating them with metal for composites with no shrink.

polyfractal12:52 PM
ooh interesting, will check out Virtual Foundry!

Thomas Shaddack12:52 PM
I tried some localized thermal laser decomposition of copper oxide in epoxy. it indeed created copper.

Thomas Shaddack12:52 PM
metal matrix composites???

Thomas Shaddack12:53 PM
thought: MMC done by electroforming on carbon fiber.

morgan left  the room.12:53 PM

Ahron Wayne12:53 PM
@polyfractal ++

perlsackhd12:53 PM
@polyfractal microgravity should also avoid separation

Ahron Wayne12:54 PM

polyfractal12:09 PM
sorta followup on the v2 subject, one variation I'm considering next is a "chromatic confocal", which scans the full Z-stack simultaneously. It's a really clever setup which "abuses" chromatic aberration to determine the height. They are considerably faster than regular confocals if you don't need fluorescense, etc and just want heightmaps

polyfractal12:10 PM
@Hexastorm will take a look after, cheers for the link!

Lageos12:10 PM
Ist it possible with the your icspi afm to take force curves to get local material parameters?

Dan Maloney12:11 PM
That's really cool. What special about the "specially designed lens" - designed to maximize chromatic aberration, I suppose?

Nicolas Tremblay12:11 PM
Doesn't the chromatic confocal get influenced by the color of the sample?

Hexastorm12:11 PM
@polyfractal project is here https://hackaday.io/project/21933-open-hardware-fast-high-resolution-laser ... you should also check out the startup spiden.com they have an interest in your work and use light + ai to detect biomarkers, anyhow enough promotion 😉

polyfractal12:12 PM
@lageos I _think_ it can take force curves (i saw mention in the manual) but to be honest I haven't played with it yet so can't really say much else. I think it's part of the advanced config/settings i haven't really touched yet

perlsackhd12:13 PM
@Dan Maloney The lense is needed so that the diffrent Wavelengths have diffrent focal distances

polyfractal12:14 PM
@Dan Maloney Yep, pretty much. I think they are known as "hyperchromatic" lenses, but i believe you can also stack up a bunch of spherical lenses and stretch out the colors

polyfractal12:15 PM
@Nicolas Tremblay yeah, my understanding is that some of the "special sauce" in the commercial units is the software that helps determine when it sees a peak, since color does affect the absolute amount returned. but in theory with a good spectrometer and some intelligent thresholding you can work around it. Nanovea and the other companies claim it works on all colors and reflective so there's _some_ way to do it

polyfractal12:17 PM
@Hexastorm that's neat! Definitely going to have a closer read. I'm noodling over a direct write laser lithography system in the future so this would be good reading for that too :)

Nicolas Tremblay12:17 PM
Ok, so the error correction is mostly on the software side with a bit of pre-filtering.

kjansky112:17 PM
I'm surprised you haven't delved into a self hacked SEM.

polyfractal12:18 PM
yeah, that's at least how I've interpreted it based on some papers and noodling over the commercial units marketing material :) but i'm sure the devil is in the details, as I learned with the regular confocal hehe

Thomas Shaddack12:18 PM
Random thought. Confocal microscope, using two-photon process for curing photoresists with resolution quite below the diffraction limit.

Dan Maloney12:18 PM
Read that as *curling*, was confused

Thomas Shaddack12:19 PM
if the resist is curling, your adhesion to substrate sucks. :P

polyfractal12:19 PM
:D

polyfractal12:19 PM
@kjansky1 yunno, I keep wanting to (there are some cool papers for mini SEMs using permanent magnets!) but tbh my EE skills are terrible, and HV scares the daylights out of me. Slowly working on learning more because I'd love to, but yeah, the electronics part is my nemesis. Really want to work on a focussed ion beam even more than SEM actually, but same issues

Thomas Shaddack12:21 PM
The danger of HV depends more on the deliverable current (and energy). You can get dozens to maybe hundreds kV from static spark. It's the current that kills, the voltage only pushes it through.

Birk joined  the room.12:21 PM

Ahron Wayne12:21 PM
And then to be even more specific, if you have a high voltage across your body, you will also have a high current going through it too. V=IR is always always always true.

Hexastorm12:22 PM
@polyfractal , have you ever considered laser induced forward transfer? would be curious to see a simple setup

polyfractal12:22 PM
good to know! actually on that note, if anyone has recommendations on HV texts/tutorials/etc I'd be grateful! Sometimes hard to find good learning resources that aren't like "Build a tesla coil!" style resources

Ahron Wayne12:22 PM
Also I just wanted to comment that it's cool you have a bio background before this. I started in biochemistry and the transition to engineering was interesting to say the least.

Thomas Shaddack12:22 PM
Depends on how "hard" the power supply is. If it is weak, the voltage quickly drops.

kjansky112:23 PM
Read somewhere of a hacked SEM with a reworked gun from a old CRT for the beam.

Nicolas Tremblay12:23 PM
For HV, go look up Plasma Channel. He might help you

Hexastorm12:23 PM
@polyfractal how long did it take you to make the laser confocal video (excluding construction) ?

Dan Maloney12:24 PM

https://hackaday.io/event/174398-into-the-plasmaverse-hack-chat

HACKADAY

Into the Plasmaverse Hack Chat

Jay Bowles will host the Hack Chat on Wednesday, September 23, 2020 at noon Pacific Time. Time zones got you down? Here's a handy time converter! Most kids catch on to the fact that matter can exist in three states -- solid, liquid, and gas -- pretty early in life, usually after playing in the snow a few times.

Read this on Hackaday

Spida12:24 PM
Anybody here knowledgeable about DIC (differential interference contrast), especiallyin the reflected light variant? how does the choics of a DIC prism depend on the lens?

Dan Maloney12:24 PM
We had Jay on last year!

Nicolas Tremblay12:24 PM
@Dan Maloney , yup, that was a fun one :P

polyfractal12:24 PM
@Hexastorm yes! I love that you know of the technique, it's super cool. I've tried a few times but haven't had a lot of luck getting "clean" transfer. just molten splatter, or complete vaporization. Part of the issue I think is the laser software -- the literal worst software ever made, EzCAD -- which makes it hard to precisely control the beam. E.g. hard to drop a single pulse where you want it. But I think it should be doable with a bit more tuning, it's pretty trivial to get "large" transfer like copper from one slide to another

a.uebener joined  the room.12:24 PM

polyfractal12:25 PM
Will check out Plasma Channel, thanks!

polyfractal12:26 PM
@Ahron Wayne yay another bio! Yeah I imagine transferring into a real engineering role would be quite a change :) Software was a decent side-move for me since I always did software stuff on the side (originally was a CS major)

polyfractal12:27 PM
@Hexastorm like just the filming/editing part of the video?

Hexastorm12:27 PM
@polyfractal yes

Thomas Shaddack12:27 PM
I did some experiments with control of a CO2 laser. Notoriously hard to get low power from the tube, the discharge won't light/stay at low currents. but the power supply responds *fast* so the amount of energy delivered can be easily controlled by the pulse time, which is easy to generate with a spare timer on the arduino with just a bit of patch of Marlin.

perlsackhd12:27 PM
@polyfractal What project would you recommend for a beginner who wants to dip his toes in diy microscopes?

polyfractal12:29 PM
gotcha. Filming is typically a few hours tops. I like to just let the camera roll and do takes until I'm happy with the delivery, then move on to the next section and repeat. Afterwards grab any b-roll as required. Makes editing longer though since there is like 2 continuous hours of footage to work through. Editing is probably 5-6 hours total, plus thumbnails and all that jazz. but yeah after a project is "done" i can usually get the video part done in a weekend'ish

Birk12:29 PM
Uhm... So that's it? Just a bunch of people chatting?

Uwe Kackstaetter joined  the room.12:29 PM

Ahron Wayne12:29 PM
That would be the case if I was ever in a "real" role, still goofing off in an academic setting :) I have considered being in software just because it's so in demand and it's accessible for work. Not sure if my Python skills are good enough for a "real" job though.

@perisackhd I would recommend you start relatively macro, like with a USB microscope or RPI lens flipped backward. Or you can work with an existing project like openflexure.

polyfractal12:30 PM
@Timo afraid I don't know much about how DIC works, only used it as an end-user in lab :(

Ahron Wayne12:30 PM
@polyfractal did you have a "big break" when it came to making videos, or did you have a steady clip of subscribers from the beginning?

polyfractal12:33 PM
@perlsackhd ++ what @Ahron Wayne mentioned. OpenFlexure is a pretty great little ecosystem. Or just hooking a microscope objective up to an RPi camera yourself, the simplest form is just an objective + camera. Make sure to get a non-infinity objective, they are typically around 160mm. meaning the camera just needs to be 160mm away. The infinity lenses are focused to infinity which is great when you need other stuff in the optical stack (like beamsplitters, etc) but complicates things since you'll need another lens to focus it onto the camera

Dan Maloney12:33 PM
@Birk -- that's why we call it a "Hack Chat"

Nicolas Tremblay12:33 PM
Open flexure seems like a great start to get into "optical" microscopy

Dan Maloney12:33 PM
Feel free to join in with questions, though

kjansky112:34 PM
How about something like this: Fiber-optic confocal microscope using a MEMS scanner and miniature objective lens

HJ Shin, MC Pierce, D Lee, H Ra, O Solgaard… - Optics …, 2007 - osapublishing.org

polyfractal12:35 PM
@Ahron Wayne definitely had a "big break" moment. I was slowly accumulating subscribers up until about 5-6k, then the YT algo decided to push a ton of traffic to my high speed chatter video and that really blew up the subscriber count. Ben Krasnow also noticed the copper deposition video and tweeted, which brough in a lot of cool folks :)

Ahron Wayne12:35 PM
@perlsackhd and not to gotcha @polyfractal but if it's non-infinity, it doesn't have to be *exactly* that distance away (something I worried about when I got into macro). If the lens is closer to your sensor the image will just be less magnified.

polyfractal12:36 PM
++

Ahron Wayne12:36 PM
@polyfractal I indeed first saw you through your high speed chatter video. 5-6k is still really great to me too.

Dan Maloney12:36 PM
Cough cough, Hackaday ;-)

polyfractal12:36 PM
that's actually one thing i like (and sometimes curse) about optics, there's a lot of manual fiddling/tuning you can do to get things working. and it's relatively accessible since you can stick a piece of paper in between lenses to see what's going on

Dan Maloney12:36 PM

https://hackaday.com/2020/01/16/analyzing-cnc-tool-chatter-with-audacity/

HACKADAY DAN MALONEY

Analyzing CNC Tool Chatter With Audacity

When you're operating a machine that's powerful enough to tear a solid metal block to shards, it pays to be attentive to details. The angular momentum of the spindle of a modern CNC machine can be trouble if it gets unleashed the wrong way, which is why generations of machinists have developed an ear for the telltale sign of impending doom: chatter.

Read this on Hackaday

polyfractal12:36 PM
hehehe

polyfractal12:37 PM
:) <3 HaD

Dan Maloney12:37 PM
Think that was the first time I had seen one of your vids, actually, so it probably was that mysterious YT algo push.

polyfractal12:37 PM
and yeah, I was pleased as punch at 5-6k! didnt know what to do with myself when it like tripled in a week :)

polyfractal12:38 PM
the YT algo gods move in mysterious ways

perlsackhd12:38 PM
@polyfractal I too saw the chattering video first then long time nothing and after seeing the LSM video remembered the Chattering video

Ahron Wayne12:38 PM
What is a video that you worked really hard on, or just otherwise wish got a lot more attention?

polyfractal12:39 PM
@kjansky1 just had a quick skim, that looks really neat! only downside is that fiber stuff can sometimes be expensive, but it does remove a lot of the alignment issues too which is great, and the fiber itself acts as the pinhole, etc etc

lilykorea9 joined  the room.12:39 PM

lilykorea912:39 PM
heyy

lilykorea912:41 PM
i need help plss

lilykorea9 left  the room.12:42 PM

polyfractal12:42 PM
@Ahron Wayne hmmmm, good question. I have a soft spot for a video about hollow microlattices, sorta based on a Science paper, which for various reasons didn't do super well (at the beginning of my transition to material science topics, too much faffing around in the beginning, etc). but I thought it was a neat topic :)

More recently I did a video about sputter shadow masks, but included a Blade Runner trailer spoof and was too cutsey with the title/thumbnail which really penalized traffic. oh well :)

polyfractal12:43 PM
obligatory hackaday link to save Dan having to go digging for it :)