Real keyboard science, not Yo Momma's lab report [FC660C domes]

[intelli78]

Gentlemen, I present to you keyboard science, the like of which the world has never seen the like of which.

Ok, so VesperSAINT and I were talking about the dome weighting on the FC660C in this thread. I have owned 3 different Leo FC660Cs, and based on my experience with them, I believe that the later models have substantially heavier weighted domes than the earlier ones, even approaching RF 55g territory. I have seen other users make similar comments on GH, so I wanted to resolve this.

So, I did some real keyboard science.

Hypothesis

H₀: There is no difference in dome weighting between my older model and my newer model
H₁: The dome weighting on the newer model is heavier than that of the old model.

Procedures and Data Collection

I currently have 2 FC660Cs in my possession. A blank one I purchased new from EK in Feb 2014 and have used as a daily driver since then. Serial #944. The second one, printed, I purchased from another user who got it as part of an early batch last year, and used it for 2-3 months. Serial #419. So, to the best of my knowledge, they have been used an approximately equal amount, canceling out any potential difference due to "break in."

I popped off a bunch of keycaps on both keyboards, like this:





Perfect for using nickels (5 grams each). The home row is nice and flat, and with surrounding keys popped off, there is no interference with the distribution of weight.

I gently added nickels on top of each of these five keys until the domes collapsed, and recorded the weight in grams that finally triggered the collapse. When I was reaching the peak # of nickels, I gently slid them on from the side so as to not cause extra force due to downward acceleration. I did 10 trials for each of these five keys, and as my final data point, used the mode (hell yeah ).

Then, I did the same for the other four easily accessible keys on the home row (D, G, J, L) , for a total of nine data points per keyboard. Could have done more, obviously, but I was getting bored.

From this summary data, I could see that there was an approx. 5g difference in means in the direction I expected.




Analysis

Tested equality of variances with f test 



Accepted the null hypothesis, variances are equal, did t-test for means



I rejected the null hypothesis with a two-tailed test at p=0.05, there was a statistically significant difference in dome weighting between the two models, the later one being heavier.

Discussion/Conclusion

The data supported and confirmed my hypothesis, however my sample size was super small and there are tons of potential confounding variables here. However, the best analysis I can do with what I have suggests the new Leo's are really different. I would like to compare these results to a similar nickel test on an RF 55g. Even though the newer model had a mean depression force of 57.2g, I think my RF 55g (which is not handy right now) nevertheless feels heavier.

Good news: if any of you guys want to repeat the nickel test using the procedure I outlined above, I can collect your data and add it to my analysis and we can try to corroborate the hypothesis, and/or get a sense for what serial numbers have the new, heavier domes 

SCIENCE, *****es

[Flyersfan1]

A+ on your lab report! Well done sir.

[AKIMbO]

Aww shi.....I love statistics.

[nubbinator]

Aww shi.....I love statistics.

I love methods, hate the stats.

That said, come on people, we need an n of at least 30 for each model of keyboard so that we can hit statistical significance.  And yes, that means that you should ideally be running a total of 30 tests on different switches on the keyboard in order to eliminate outliers and confirm statistical significance.

Let's science this *****.

[Sifo]

Maybe when I'm not lazy I'll dump all my spring data.

[drinkbleach]

Aww shi.....I love statistics.

I love methods, hate the stats.

That said, come on people, we need an n of at least 30 for each model of keyboard so that we can hit statistical significance.  And yes, that means that you should ideally be running a total of 30 tests on different switches on the keyboard in order to eliminate outliers and confirm statistical significance.

Let's science this *****.

I have a blank sn #623. I can test with Canadian nickels that weigh 3.95 g. Or see if I can go to bank and get me some US change

I'll report back with my findings

[exitfire401]

I can't lie...just did this **** in stats, and I absolutely hate it, but you've definitely put it in terms I can understand.

[nubbinator]

I can't lie...just did this **** in stats, and I absolutely hate it, but you've definitely put it in terms I can understand.

There's a reason I tried to stick with qualitative work for my Master's thesis and other research designs.

[intelli78]

[quote author=drinkbleach
I have a blank sn #623. I can test with Canadian nickels that weigh 3.95 g. Or see if I can go to bank and get me some US change

I'll report back with my findings
[/quote]

Cool!

[CPTBadAss]

****, now I want to get a FC660C to play too. This is really cool, thanks for sharing.

[MythicalWagyu]

Serial # 681 (printed) reporting in; currently acquiring nickels, but I'll set aside some time this weekend to test as described by Nubbinator (30 tests on different switches on the keyboard) so I can add to your data pool. Oh and thanks for sharing, this is really interesting stuff!

[johndavis33]

I love stats! Maybe you can do a chi squared test for homogenity between all the claimed 45g topre boards? I've heard people say they don't all feel the same.

[user 18]

Question: Would it not have been better to use the same keycaps for tests on both boards, so you could eliminate any variance in cap manufactured weight?

A slightly heavier (thicker?) cap could be the difference between say a 50cn and a 55cn actuation, particularly if the true point of actuation is somewhere around 51cn.

Like the stats work, but I agree we need a larger sample size for statistically significant data. If someone feels like buying me a 660C, I'll happily contribute

[blingcaps]

wow, these findings definitely match up with my experience.  i got my 660c a month or two ago, and the "45g" is definitely noticeably heavier than my "45g brown".

[daerid]

Dye Sub PBT arriving on Monday, will report nickel findings then

[SpAmRaY]

Dye Sub PBT arriving on Monday, will report nickel findings then

Don't leave us hanging!

[daerid]

Nothing quite so comprehensive as the OP's, but here are my results:

5 keys tested (D, G, J, L, Right Arrow)

FC660C (Serial Number 452): 13 nickels
RealForce 55g: 14 nickels

I'm actually quite surprised by these results. For an advertised 45g board, my nickel test indicated that the 660C requires an average of 60-65g per switch, whereas the 55g RealForce requires 65-70g.

I'd normally be skeptical of these numbers, but the test isn't particularly hard to perform: 1) stack nickels on a switch until it actuates 2) count nickels.

[gh_pp]

Nice report. I hate heavier switches. On the bright side I'll never go smaller than TKL so the leo is not a acquisition target.

Damn, many many moons ago I got A+ on both advanced stats courses in college.
Now reading this I can only vaguely remember what I learned, yet I can't make sense of the whole thing. So sad

[intelli78]

Update: I made a video to demonstrate the difference in typing sound/volume: http://geekhack.org/index.php?topic=60984.0

[Demetrium]

Science!

[MythicalWagyu]

I'm slowly working on gathering weighting data on my Leopold... so far the keys have been coming in at 55 - 60g collapse, 25-30g reset. They definitely feel heavier than my HHKB but I won't know for sure until more science

I am wondering if I should fux with some pennies to get a more fine-grained measurement* but it may take kind of a ridiculously high stack to activate the switch )
^{* http://www.usmint.gov/about_the_mint/?action=coin_specifications}