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geekhack Projects => Making Stuff Together! => DIY Discussions ARCHIVE => Topic started by: huha on Fri, 31 July 2009, 10:38:05

Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: huha on Fri, 31 July 2009, 10:38:05: Will it blend?

My bet: 2 m until most rivets are gone.

-huha
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: JBert on Fri, 31 July 2009, 12:47:50: This is madness!
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: Rajagra on Fri, 31 July 2009, 13:47:32: Quote from: JBert;105869
This is madness!

Madness?

This ... is ...

...GEEKHACKER!
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: itlnstln on Fri, 31 July 2009, 14:32:48: Quote from: ripster;105871
Did the 4 foot, 5 foot and TWO 6 footers. Still losing only 2 to 3 rivets per drop.

Hmm... gotta take the dog on a walk and think about this.

Maybe the plastic ages in such a way that it becomes more brittle over time. Therefore, this newer keyboard's rivets won't break as easily.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: o2dazone on Fri, 31 July 2009, 15:13:11: lmao

(http://geekhack.org/attachment.php?attachmentid=3487&stc=1&d=1249070850)

Ripster, you make this forum so entertaining
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: itlnstln on Fri, 31 July 2009, 15:45:40: Quote from: webwit;105911
I would sue them if they were too cheap to use nuts and bolts and used melted plastic instead.

That's what is perplexing about the M. I know they were trying to save cost, but with all the high-quality parts on the 'board, would it have been too much to ask for them to use metal rivets?
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: talis on Fri, 31 July 2009, 16:04:25: I don't know that they all needed to be metal screws, but a few probably would have helped. I think the pre-melted plastic rivets probably helped to register the membrane and matrix on the rest of the board as it went down the production line.

Even a screw at each of the 4 corners + 2 in the center would likely have taken most of the stress of a drop off the rivets.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: ch_123 on Fri, 31 July 2009, 19:29:48: Ref III? Ref I? What is all this terminology?
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: ch_123 on Sat, 01 August 2009, 11:49:56: Plastic? I thought the hammers where made of something conductive and they made the contact on the membrane. How does it work then?
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: CX23882 on Sat, 01 August 2009, 14:23:19: Sturdy keyboard. I guess we don't need to worry about the build quality or longevity of a Unicomp versus an old IBM board.

I wonder what MythBusters would end up doing if they tried to bust the myth of the indestructable Model M? C4 explosives?
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: keyb_gr on Sat, 01 August 2009, 14:37:45: Nah, a bottle of coke might do...
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: huha on Sat, 01 August 2009, 18:53:07: For science? This clearly is Destroying a Boscom For Fun And Profit.

Quote from: ripster;106029
Next time someone opens up a F please check the hammers - my bet is they are conductive plastic (carbon added to the mix).

While that would also be my bet, please be adviced that this doesn't neccessarily need to be the case. You'll just need something with a different dielectric constant between the capacitor plates to change capacitance. Plain non-conductive plastic could work as well, but since the electronics need to be cheap, large changes in capacitance are desirable, leading to large differences in dielectric constant for the materials used for the hammer. However, you could also beef up electronics and just use a regular plastic hammer assembly.

-huha
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: Specter_57 on Sat, 01 August 2009, 19:18:11: Ummm...

would it be possible to photograph the front and back of the PCB Controller board and post those pics here?
(Preferable with the cct board in one piece....)

Thanks
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: o2dazone on Sun, 02 August 2009, 02:58:16: Animated gif owns f-f-f-f-f-f-fire
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: ch_123 on Sun, 02 August 2009, 06:14:37: Quote from: huha;106114
Plain non-conductive plastic could work as well, but since the electronics need to be cheap, large changes in capacitance are desirable, leading to large differences in dielectric constant for the materials used for the hammer. However, you could also beef up electronics and just use a regular plastic hammer assembly.

Trust me, value for money didn't seem to be the primary concern of whoever designed these keyboards. I think I remember seeing a price tag of $300-350 for the original PC/XT keyboard if you were to buy it seperately from IBM, but I can't find any more info on it. By means of comparison, the Model M was selling for about $150 in it's heyday. Both prices are in at-the-time dollars, so you could have probably bough a Topre or two with that kind of money.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: keyb_gr on Sun, 02 August 2009, 07:50:11: Quote from: ripster;106153
Although it ended up burning it took a while to start.

That's expected with the usual dose of retards, err, flame retardants.

Kinda reminded me of this (http://www.ban.org/photogallery/nigeria_lagos/pages/vidpic_burningtv2.html) though.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: huha on Sun, 02 August 2009, 09:47:32: Quote from: ch_123;106164
Trust me, value for money didn't seem to be the primary concern of whoever designed these keyboards.

Value for money always is the primary concern of whoever designs electronics. It's just cheaper to use a material with a vastly different dielectric constant than to beef up measurement electronics to be able to accurately measure tiny fluctuations in capacitance when using standard plastic.
This doesn't compromise functionality at all, but you just don't need lab-grade equipment in a keyboard. There could be many ways of alternative keypress detection, but it'll just become horribly expensive when you need accurate equipment to measure it.

Also, burning plastic in a bonfire might be fun, but it won't tell you anything about the plastic. Best test is to heat it gradually and look for the temperature it starts to deform, then to burn it on its own, using just a small ignition source (quite hard with flame retardants), note the temperature at which that happens and observe burning characteristics (smoke/soot), smell etc.

PVC should be quite easy to tell from the smell.

-huha
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: keyb_gr on Sun, 02 August 2009, 11:59:11: Quote from: ripster;106198
P.S. You DON'T want to smell these fumes - nasty! We doused the flame soon after the last pic.

From PVC I'd expect something rather unpleasant, given the chlorine. Then again, I wouldn't expect very inviting smells in any case.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: rdh on Sun, 02 August 2009, 13:00:07: Quote from: ch_123;106164
I think I remember seeing a price tag of $300-350 for the original PC/XT keyboard if you were to buy it seperately from IBM, but I can't find any more info on it. By means of comparison, the Model M was selling for about $150 in it's heyday.

This is rather tangential, but I ran across a couple of keyboard reviews from 1985 or so:
New York Times (http://www.nytimes.com/1985/07/23/science/peripherals-comfortable-keyboards.html?&pagewanted=all)
Creative Computing (http://www.atarimagazines.com/creative/v10n10/20_A_new_keyboard_for_the_PC.php) magzine

The prices mentioned are in the $200 - $260 range, plus a $400 KeyTronic that apparently included a touchpad of some sort (in 1985!).

I didn't find anything indicating the price of the IBM keyboards themselves, but the reviews were fun to read.

The conclusion in the Creative Computing article still rings true:
Quote
Keyboards are rather personal. Once you get used to one, it can be traumatic and time-consuming to adapt to another.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: keyb_gr on Sun, 02 August 2009, 13:43:56: Cool find.
Quote from: Creative Computing
Do not overlook the weight of the keyboard, especially if you use it on your lap most of the time. The PC keyboard is fairly heavy, and after using it for a few hours, you might feel that circulation to your legs has been cut off. A lighter keyboard reduces fatigue and is easier to move about.
Right on. That is precisely why I prefer to give a Model M (which seems to weigh about as much as the PC Model F, they state 5.1 pounds = 2.3 kg) a (semi-)fixed position on the desk while those that may be moved around and stored under the desk are much lighter G80s.

Their insistence on explicitly labeled Shift, Backspace and Return keys is hilarious though.

I wonder what kind of switches the various boards used.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: keyb_gr on Sun, 02 August 2009, 14:46:44: Quote from: ripster;106231
Show Image
(http://geekhack.org/attachment.php?attachmentid=3532&stc=1&d=1249237738)

What's under that sticker?

The PCB looks quite cheap.

Maybe you could use that one for a nice little BS numpad?
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: JBert on Mon, 03 August 2009, 09:24:46: Quote from: keyb_gr;106235
What's under that sticker?

The PCB looks quite cheap.
I wouldn't call that cheap.
Sure, it has no silk-screened print on both sides, but then again, is that really needed? Or is there some criterion I'm missing?

Anyway, I think you can still shorten it with 5mm to fit in the remnants of your Boscom.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: lowpoly on Mon, 03 August 2009, 14:48:04: Quote from: ripster;106198
May be some EU regulations here too - the Boscom isn't stamped at all so maybe that's why some Unicomps can't be sold in Europe.

I have the german version of the Boscom.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: itlnstln on Mon, 03 August 2009, 14:53:02: Quote
May be some EU regulations here too - the Boscom isn't stamped at all so maybe that's why some Unicomps can't be sold in Europe.

I think the USB versions of any of the Unicomp 'boards could not be sold in Europe due to some regulations of some sort.
Title: Ripster...and the Circuit Board pics
Post by: Specter_57 on Tue, 04 August 2009, 09:28:16: Thank you for posting those pics.

They appear, on the surface, to be pretty much what I expected as to ribbon connector and the IC (40 pin, as expected).

Likely a relatively slight programming change as compared to the 122-key Terminal Keyboards I have.

Was curious to get a look at one of these controller boards for that keyboard.

Again, Thanks.

Spec57
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: ch_123 on Tue, 04 August 2009, 11:09:24: An idea for a test came to me earlier, but it's probably too late now. Try chopping a little bit off the front of the barrel, not enough so that the key-stem can't slot in and go up and down properly, but enough so that the spring doesn't hit anything when it buckles. It would test whether or not the spring hitting the barrel has any effect on sound.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: ch_123 on Tue, 04 August 2009, 11:34:55: Interesting... Did you try weighing the springs on a kitchen scale?
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: ch_123 on Tue, 04 August 2009, 15:23:40: I think it's safe to say that they're made from the same stuff. That pretty much eliminates the only easy explaination for the difference in sound and resistance. The only possible caveat with your weighing is that you should have weighed the springs seperately to the hammers. Obviously though, the odds that there's a difference in the weight in the springs that is counteracted by an equal difference in weight in the hammers such that the net weight difference of both is canceled out is extrememly unlikely... Still, one should always strive to be completely accurate.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: ch_123 on Tue, 04 August 2009, 15:26:36: Quote from: itlnstln;106570
I think the USB versions of any of the Unicomp 'boards could not be sold in Europe due to some regulations of some sort.

To be specific, the USB EnduraPro cannot be shipped outside America. The USB Customizers and SpaceSavers are fair game.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: talis on Tue, 04 August 2009, 16:17:58: Quote from: ch_123;106873
An idea for a test came to me earlier, but it's probably too late now. Try chopping a little bit off the front of the barrel, not enough so that the key-stem can't slot in and go up and down properly, but enough so that the spring doesn't hit anything when it buckles. It would test whether or not the spring hitting the barrel has any effect on sound.

You can also try just using a key cap and the spring/foot assembly in your hands. You'll notice the clicking sound when you compress it is very close to the clicking sound you experience with the normal keyboard assembly.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: keyb_gr on Wed, 05 August 2009, 03:12:10: So it's neither the spring assemblies nor the rivets. Must be the plastic actuator panel then, which I already found to be responsible for a difference in friction when swapping around keystems.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: microsoft windows on Sun, 09 August 2009, 12:13:07: Now I know that I don't have to worry if someone spills nail polish on my key-caps!
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: kode on Sun, 09 August 2009, 12:50:58: Quote from: ch_123;106975
To be specific, the USB EnduraPro cannot be shipped outside America. The USB Customizers and SpaceSavers are fair game.

Right. I asked them about that two years ago, and if they had any idea whether this would change. The answer I got from Jim was "I do not see it happening in the next couple of months." Well, yeah.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: ch_123 on Sun, 09 August 2009, 13:06:09: I got a PS/2 one and a Belkin adaptor that worked just fine, so it didn't really bother me that much.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: Shawn Stanford on Wed, 26 August 2009, 18:47:47: I've been watching this thread on and off and I just remembered that my daughter knocked a Model M off the stairs and to the floor below a couple years ago. It fell about five or six feet and landed on the wooden floor. Keycaps and a few keys exploded everywhere but, after it all went back together, it worked perfectly and has ever since.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: ch_123 on Fri, 28 August 2009, 10:02:58: Does the keyboard still function after spilling coke all over it? Or have all the previous tests killed it anyway?
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: ch_123 on Fri, 28 August 2009, 11:22:53: Do you manage to get your hands on some Model F springs?
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: o2dazone on Fri, 28 August 2009, 12:42:41: I like how you can see the drainage holes start pouring coke one after the other lol. Nice testing! always entertaining
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: ch_123 on Tue, 01 September 2009, 10:47:08: Well, wouldnt the Model F spring be too long for the Model M? I think the length has to be exactly right for the spring to function properly. That, or a certain force is needed to activate the membrane. Hard to know...

Really what you need to do is get one of those cheap Model C2s and do the same thing you did to the Boscom :p
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: Shawn Stanford on Tue, 01 September 2009, 11:05:40: I once temporarily lost a spring while cleaning a Model M and replaced it with a click-pen spring. IIRC: I had to cut it down and squish it into an oval shape to fit into the tube, but it worked more-or-less the way it should have. It did give a different feel, but I wasn't analyzing it at the time.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: ch_123 on Tue, 01 September 2009, 11:07:15: Ah, I somehow managed to miss that pic in your post...

Maybe then it's related to some kind of activation force for the membrane?

Oh, and were you using two piece keycaps with the Model F spring? Because I once tried them out on my Model F and it made them feel really mushy.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: ch_123 on Tue, 01 September 2009, 11:41:17: Well, there was definitely a substantial difference on my Model F, not as much on my Unicomp though...
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: itlnstln on Tue, 01 September 2009, 13:10:24: I would imagine there is a quantifiable difference between different caps depending on construction and materials. I can definitely feel a difference between Filco and Cherry caps.

The problem is how to quantify it. Personally, I don't care beyond what I feel and that feel drives my purchases. Someone might have the ambition to see how different plastics (ABS vs. POM) and different constructions (double-shot vs. silkscreened) transmit vibrations/absorb impact, flex, etc.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: itlnstln on Tue, 01 September 2009, 13:33:47: Quote from: ripster;113730
How boring....

That's what I think, but somehow I have a sneaking suspicion that's the next thing the Boscom's going to be contracted to do (along with some other keyboards).
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: timw4mail on Tue, 01 September 2009, 13:38:28: Well, obviously harder plastics would create noisier, more tactile keys. Also, the tighter the keycap fits, the more tactility and sound directly transferred and amplified by the keycaps.

So, really there shouldn't be that much experiment involved, other than knowing the relative differences in hardness between different keycap plastics.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: JBert on Tue, 01 September 2009, 15:24:07: Hmmm, there should be a way to measure spring strength...

Also, what difference may the rockers, key housing and keycaps make? With such a subtle mechanism, couldn't it be that they also cause the spring to buckle differently?
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: kode on Tue, 01 September 2009, 18:28:51: I have been sort of pondering on this, that if I were to get hold of springs with same measures, and varying amount of coils, would it not perhaps be possible to implement a realforce/ergoforce style scheme of differently weighted springs. What I'd really be after is a way to shorten the travel needed for the click, I guess...
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: msiegel on Sun, 18 October 2009, 13:56:11: boil a lego?? u blast-femur!

(go science! :)
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: msiegel on Sun, 18 October 2009, 18:23:43: yes! ibm & unicomp ftw :)

plastic is *not* boring

btw, that last culture break is grrr8 :D
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: msiegel on Sun, 18 October 2009, 18:36:01: now you're cookin. i suspect pvc :)
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: msiegel on Sun, 18 October 2009, 18:44:57: Delrin melts at 347F. Excellent resistance to acetone.

http://www.machinist-materials.com/comparison_table_for_plastics.htm
http://k-mac-plastics.net/data%20sheets/delrin_chemical_resistant_chart.htm
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: Rajagra on Sun, 18 October 2009, 19:03:39: Quote from: ripster;126743
Water boils at...?

How high do you want it to?
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: microsoft windows on Sat, 07 November 2009, 18:34:20: Looks like the IBM key plastic myth hasn't been busted yet!
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: keyb_gr on Sun, 27 December 2009, 14:43:47: Bumpety-bump.

About ripster's oddball Cherry key, well, my G80-3000HEMDE also obviously has its Windows and Menu keys made from a different material than the others, since only those are yellowed a bit on top (and only on top)! Looking underneath, they aren't doubleshots either. Ripster, what vintage was that POS board?

Here's a good overview of service temperatures and other properties (http://www.gehr.de/dyndata/20080408_DE_neu_GEHR_datenvergleich_der_einzelnen_kunststoffe.pdf) that I found. PS seems to be similar to ABS (http://www.matweb.com/reference/deflection-temperature.aspx). This Wiki (http://www.substech.com/dokuwiki/doku.php?id=thermoplastic_polyvinyl_chloride_pvc) and this website (http://www.tangram.co.uk/TI-Polymer-POM.html) are quite interesting as well.

I don't think one would be able to tell apart PS and ABS in homebrew boiling and acetone tests. Should work for PVC though. POM, PC, PP and PBT would all be rather unimpressed. Unsure what a PC/ABS blend might do - sounds like a case (no pun intended) for the poor old Boscom.

Hmm, I wonder whether those old Cherry doubleshots might have been from PP - apparently it does yellow.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: keyb_gr on Mon, 28 December 2009, 06:59:01: Another hint (http://geekhack.org/showpost.php?p=145845&postcount=39):
Quote from: InSanCen
[...]as the cases on M's are not suited to Rit Dye (the keys take it well though)[...]
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: msiegel on Tue, 19 January 2010, 18:49:57: i miss chloe.
pbt would be better for ibm's dye sub process, wouldn't it :)
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: msiegel on Tue, 19 January 2010, 19:37:40: google translate mangles that page pretty badly.

it does say pbt though :D

i wonder how the author found out.
Title: Destroying A Boscom For Science - Can the Rivets survive a 6 foot drop?
Post by: itlnstln on Wed, 20 January 2010, 07:52:09: Quote from: ripster;152192
Another post from that thread from Chloe. (http://geekhack.org/showpost.php?p=76463&postcount=205)

She suspects the IBM and Topre keys are PBT. Could be.

Actually, she doesn't (at least not in that post). She simply states that they are probably not ABS. They could be POM, PVC, PBT, or something else. I would speculate that Filco keys are ABS, though.