Forums

OT: Science of dropping things

Started by bitrex April 9, 2016
On Sun, 10 Apr 2016 00:22:12 -0500, the renowned "Tim Williams"
<tiwill@seventransistorlabs.com> wrote:

>"John Larkin" <jjlarkin@highlandtechnology.com> wrote in message >news:hccigb9fms4e0atgjv2dotecf7tvkihmvk@4ax.com... >> Parts are getting smaller a lot faster than we're getting older. 1206 >> resistors used to seem impossibly small. I was soldering some >> yesterday and they looked gigantic. Even 0805 looks big. > >Pfft, 0603 is average, 0402 and below is where things get tiny.
What's amazing to me is how perfect the 0603 and 0402 parts look under a microscope, for something that is almost free to buy. Radiused edges and radiused metalization, smooth ceramic. My tweezer ends look crude by comparison.
> >Not-bragging-bragging about my still young eyes, of course ;-) > >> I just got a board with 60 mil high reference designators; they are >> tiny but beautifully sharp. Yesterday I asked the younger people in >> production if they would mind my going to 50 mils. They all said no >> problem, we need magnification to see this stuff already. > >Geez, those are bigger than the components. > >I've received 25 mil text which was legible, but that's pushing it. I use >30 (6 line width) for most SMTs. 60 (occasionally more) is reserved only >for bulky THTs that you're expected to see while plugging things in. > >> Our senses are limited in dealing with electronics. We need a lot of >> fancy and fun instruments. > >Wouldn't mind a Mantis like you've got, but a loupe is quite handy for >inspecting those things my eyes aren't really sharp enough to resolve in the >first place. > >Tim
-- Best regards, Spehro Pefhany Amazon link for AoE 3rd Edition: http://tinyurl.com/ntrpwu8
bitrex wrote:
> On 04/09/2016 03:42 AM, DecadentLinuxUserNumeroUno wrote: >> On Sat, 9 Apr 2016 02:49:03 -0400, bitrex >> <bitrex@de.lete.earthlink.net> Gave us: >> >>> Is there any science about why things you drop on the floor always >>> end up in the last place you'd look? >> >> Yes. If you kept looking for them after you found them, you >> would be recommended for the loony bin. >> > > That is an excellent point.
It was a David Brenner joke on the Johnny Carson Show one night around 1977.
On 4/9/16 8:15 AM, Tim Williams wrote:
> "bitrex" <bitrex@de.lete.earthlink.net> wrote in message > news:AB1Oy.11667$S57.4599@fx08.iad... >> I'm fairly clumsy, and I drop things on the floor a lot. >> >> What often happens is that I hear something small clatter to the >> floor, like a screw, or key, or cell phone charger. I then think "Ah, >> this should be easy to find." >> >> Then I end up hunting around on my hands and knees with a flashlight >> for that screw I heard fall to the floor...and I never find it. You'd >> think if you heard it hit the ground, it would be easy to find...but >> dropped things apparently just vanish into another dimension. >> >> Is there any science about why things you drop on the floor always end >> up in the last place you'd look? > > Sure. > > 1. You hear the first hit, but less likely the subsequent bounce and > scattering. > 2. If you don't follow it quickly by eye, you won't see which way it's > bounced. Eye-ear coordination and ambiguity of hearing (your ears are > considerably less spacially accurate than you give them credit for). > 3. On the bounce, vertical kinetic energy is converted to a random > amount of horizontal. Irregular shapes bounce in random directions. > Thinking that "it sounded like it bounced over there" is somewhat > irrelevant. It also continues rolling or sliding, depending on the > surface. > 4. You're older, I think? So probably your eyesight alone isn't too > great, and even if you can get a clear scan of the floor, spotting small > objects is probably difficult (especially if you have no idea where they > are, let alone a faulty idea of where they are!). > > Idunno... seems likely to me. We generally put way too much confidence > in the performance of our senses. This subject alone doesn't seem like > something worthy of a paper ... but then, I'm no academic. They are the > pros are stretching things out to whole papers. A small-scale > controlled study, perhaps? > > Tim >
It's not only a sensing problem. Our brains fill in missing data to meet our expectations. When I was a kid, I saw an arrow fly past a tree when it had actually glanced off at a 30 degree angle. Took me ages to find that arrow. We also have an amazing ability to ignore data that doesn't fit our bias. Maybe it's due to the world's low SNR and our limited processing resources. Would AI be better if it incorporated wishful thinking? Would we just get a computer that reaches the wrong conclusions and won't accept conflicting data? I'd be happy to study it, as long as someone else raises the funds :) Are you listening Larry? Sergey? ChesterW
On 4/9/2016 11:26 AM, dcaster@krl.org wrote:
> On Saturday, April 9, 2016 at 9:53:53 AM UTC-4, mixed nuts wrote: >> On 4/9/2016 2:49 AM, bitrex wrote: >>> I'm fairly clumsy, and I drop things on the floor a lot. >>> >>> What often happens is that I hear something small clatter to the >>> floor, like a screw, or key, or cell phone charger. I then think >>> "Ah, this should be easy to find." >>> > I usually think " Damn ". > >>> Then I end up hunting around on my hands and knees with a >>> flashlight for that screw I heard fall to the floor...and I never >>> find it. You'd think if you heard it hit the ground, it would be >>> easy to find...but dropped things apparently just vanish into >>> another dimension. >>> >>> Is there any science about why things you drop on the floor >>> always end up in the last place you'd look? >> >> If you get a broom and a dustpan, and sweep up around the bench, >> 99 times out of 100, you'll find the part. > > I look first, and often shine a flashlight parallel to the floor > hoping to see a shadow cast by the dropped part. Then I try the dust > pan and it usually works.
The 3W led mini-Maglite is especially suited for that - narrow beam, very bright. 0505 chip caps pop right out.
> > Where I used work, the floor was linoleum tiles with a mottled color > which made finding dropped parts almost impossible.
I had a seamless epoxy floor in one lab (somebody broke a mercury barometer in there so it was part of the remediation process). I asked for an eye-ease green, light gray or something similar. The "architectectural advisor" chose hospital white with sparkly multicolored confetti sprinkled on under a no-slip textured clear coat. You couldn't find anything smaller than 1/4" without a broom. -- Grizzly H.
On Sat, 9 Apr 2016 15:51:40 +0800, Rheilly Phoull
<rheilly@bigslong.com> wrote:

>On 9/04/2016 2:49 PM, bitrex wrote: >> I'm fairly clumsy, and I drop things on the floor a lot. >> >> What often happens is that I hear something small clatter to the floor, >> like a screw, or key, or cell phone charger. I then think "Ah, this >> should be easy to find." >> >> Then I end up hunting around on my hands and knees with a flashlight for >> that screw I heard fall to the floor...and I never find it. You'd think >> if you heard it hit the ground, it would be easy to find...but dropped >> things apparently just vanish into another dimension. >> >> Is there any science about why things you drop on the floor always end >> up in the last place you'd look? > >I am in the same school as yourself, with the advent of SMD I don't look >anymore......just reach for the part bin.
Yes, and if you did find it, how do you know that it isn't another part that disappeared to another dimension last week and just reappeared? It's usually easier to grab a new part than measure the old one.
On Sat, 9 Apr 2016 09:53:38 -0400, mixed nuts
<melopsitticus@undulatus.budgie> wrote:

>On 4/9/2016 2:49 AM, bitrex wrote: >> I'm fairly clumsy, and I drop things on the floor a lot. >> >> What often happens is that I hear something small clatter to the floor, >> like a screw, or key, or cell phone charger. I then think "Ah, this >> should be easy to find." >> >> Then I end up hunting around on my hands and knees with a flashlight for >> that screw I heard fall to the floor...and I never find it. You'd think >> if you heard it hit the ground, it would be easy to find...but dropped >> things apparently just vanish into another dimension. >> >> Is there any science about why things you drop on the floor always end >> up in the last place you'd look? > >If you get a broom and a dustpan, and sweep up around the bench, 99 >times out of 100, you'll find the part.
Doesn't work well on carpeted floors. Carpeting makes things bounce a lot farther, too.
On Sun, 10 Apr 2016 00:22:12 -0500, "Tim Williams"
<tiwill@seventransistorlabs.com> wrote:

>"John Larkin" <jjlarkin@highlandtechnology.com> wrote in message >news:hccigb9fms4e0atgjv2dotecf7tvkihmvk@4ax.com... >> Parts are getting smaller a lot faster than we're getting older. 1206 >> resistors used to seem impossibly small. I was soldering some >> yesterday and they looked gigantic. Even 0805 looks big. > >Pfft, 0603 is average, 0402 and below is where things get tiny. > >Not-bragging-bragging about my still young eyes, of course ;-) > >> I just got a board with 60 mil high reference designators; they are >> tiny but beautifully sharp. Yesterday I asked the younger people in >> production if they would mind my going to 50 mils. They all said no >> problem, we need magnification to see this stuff already. > >Geez, those are bigger than the components. > >I've received 25 mil text which was legible, but that's pushing it. I use >30 (6 line width) for most SMTs. 60 (occasionally more) is reserved only >for bulky THTs that you're expected to see while plugging things in. > >> Our senses are limited in dealing with electronics. We need a lot of >> fancy and fun instruments. > >Wouldn't mind a Mantis like you've got, but a loupe is quite handy for >inspecting those things my eyes aren't really sharp enough to resolve in the >first place. >
I have a Mantis at work, too, but I also have one of these. They're a great addition and much better than "OptiVisors". http://www.digikey.com/product-detail/en/aven-tools/26221/243-1197-ND/1992723
On Sat, 9 Apr 2016 02:49:03 -0400, bitrex
<bitrex@de.lete.earthlink.net> wrote:

>Then I end up hunting around on my hands and knees with a flashlight for >that screw I heard fall to the floor...and I never find it. You'd think >if you heard it hit the ground, it would be easy to find...but dropped >things apparently just vanish into another dimension.
Idea: Get a security camera and attach it under your workbench pointed downward. When you drop something, merely rewind the recorded video to when you dropped it, and you might be able to see where it landed. Lighting, depth of field, frame rate, and focus will need to be determined. It probably won't see chip size parts, but might work with larger objects like hardware, leaded components, BNC center pins, etc. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
On 4/10/2016 11:37 AM, krw wrote:
> On Sat, 9 Apr 2016 09:53:38 -0400, mixed nuts > <melopsitticus@undulatus.budgie> wrote: >> On 4/9/2016 2:49 AM, bitrex wrote: >>> I'm fairly clumsy, and I drop things on the floor a lot. >>> >>> What often happens is that I hear something small clatter to the >>> floor, like a screw, or key, or cell phone charger. I then think >>> "Ah, this should be easy to find." >>> >>> Then I end up hunting around on my hands and knees with a >>> flashlight for that screw I heard fall to the floor...and I never >>> find it. You'd think if you heard it hit the ground, it would be >>> easy to find...but dropped things apparently just vanish into >>> another dimension. >>> >>> Is there any science about why things you drop on the floor >>> always end up in the last place you'd look? >> >> If you get a broom and a dustpan, and sweep up around the bench, >> 99 times out of 100, you'll find the part. > > Doesn't work well on carpeted floors. Carpeting makes things bounce > a lot farther, too.
Carpeted areas are for administrative and sales staff and presidents and stuff. -- Grizzly H.
On 04/09/2016 07:57 AM, Jim Thompson wrote:
> On Sat, 9 Apr 2016 02:49:03 -0400, bitrex > <bitrex@de.lete.earthlink.net> wrote: > >> I'm fairly clumsy, and I drop things on the floor a lot. >> >> What often happens is that I hear something small clatter to the floor, >> like a screw, or key, or cell phone charger. I then think "Ah, this >> should be easy to find." >> >> Then I end up hunting around on my hands and knees with a flashlight for >> that screw I heard fall to the floor...and I never find it. You'd think >> if you heard it hit the ground, it would be easy to find...but dropped >> things apparently just vanish into another dimension. >> >> Is there any science about why things you drop on the floor always end >> up in the last place you'd look? > > I have a magnet on an extendable wand for "sweeping" the floor. I'm > forever dropping the tiniest of screws :-( > > ...Jim Thompson >
Ummm, maybe a good addition to one of those robo-suckers...set it off & check in an hour! :-)