[Noisebridge-discuss] Step-on buttons

Taylor Alexander tlalexander at gmail.com
Wed Jan 19 12:18:42 PST 2011


It's called Fatigue.
"... fatigue is the progressive and localized structural damage that
occurs when a material is subjected to cyclic loading. The nominal
maximum stress values are less than the ultimate tensile stress limit,
and may be below the yield stress limit of the material."
http://en.wikipedia.org/wiki/Fatigue_(material)

:)

FYI aluminum is way worse with fatigue than steel. With aluminum, no
matter how low the cycled load, it will eventually fatigue. With
steel, there is a lower force limit, below which even an unlimited
number of cycles will not cause the part to fail.

However, it may still be 100k's of cycles for aluminum, and your feet
would get tired before that happened. The biggest concern would be the
spring material, but no one makes aluminum springs really anyway (for
the above reasons). Foam can wear out, but may work great. For added
longevity, maybe place a spring on top of an insulator in the middle,
and then put some contacts around that that extend past the springs
compressed limit.

-Taylor

On Wed, Jan 19, 2011 at 11:07 AM, David Kelso <david at kelso.id.au> wrote:
> Interesting. That sounds like a nice cheap way to do things. What kind
> of metal / thickness did you use? Was there any problem with the metal
> losing its spring after time? (I know there's a materials engineer out
> there who can tell me the correct term for that)
> Was the weather stripping around the outside of the metal sheets? Or
> through the middle?
>
> On Wed, Jan 19, 2011 at 1:16 AM, Sean Cusack <sean.p.cusack at gmail.com> wrote:
>> I've made my own DDR pad as well (a loooooong time ago). 2 sheets of metal
>> separated by weather stripping. When you stand on one piece of metal, it
>> bends and touches the other one. When you lift up your foot, the piece of
>> metal unbends, and breaks the connection. I've got a AA rating on a 9 foot
>> song (and some weird japanese voice on the video game told me he could "feel
>> [my] moves all over his body!!") before using this technology when I used to
>> DDR like all the time (Sean = nerd), so I think its pretty robust, and super
>> cheap.
>>
>> You can just run a wire as far as you need it to go to connect each of them
>> together.
>>
>> Sean
>>
>> On Tue, Jan 18, 2011 at 6:37 PM, David Kelso <david at kelso.id.au> wrote:
>>>
>>> Yes, sorry, I should have been more specific.
>>>
>>> I'm trying to make a big grid of buttons that you could stand on to
>>> sequence music. Each button would be separated by a few feet, so those
>>> dance pads aren't quite the right analogy. However I would definitely
>>> be interested in hearing about how they work internally. Light up
>>> would be great, or some sort of feedback, so that users would know
>>> when they're standing on it correctly.
>>>
>>> Budget is as cheap as possible while still being reliable - I'm trying
>>> to spec out the costs for a couple potential projects, and deciding
>>> which I should be going with. Quantity wise, it would be a grid with a
>>> multiple of 8 buttons. So somewhere between 32 and 64 buttons.
>>>
>>> I'm liking the sound of an optical switch with a spring loaded perspex
>>> platform. Sounds like it would be durable and easy to light up. Thanks
>>> for the suggestion Taylor.
>>>
>>> On Tue, Jan 18, 2011 at 6:20 PM, Reed Kennedy <reed at flatrabbit.org> wrote:
>>> > David,
>>> >
>>> > If you really want to know more about DDI's pads, I can fill you in.
>>> > Or you can just come look at 'em.
>>> >
>>> > Could you tell me more about what you're trying to accomplish? How
>>> > many buttons? What's your budget? Etc...
>>> >
>>> > Reed
>>> >
>>> > On Tue, Jan 18, 2011 at 4:59 PM, Taylor Alexander
>>> > <tlalexander at gmail.com> wrote:
>>> >> I know the people that did DDI basically had to make their own
>>> >> buttons, and even then I think they wore out (though I'm really not
>>> >> sure, its been like 2 years since I had a 5 minute convo about those
>>> >> buttons with someone).
>>> >>
>>> >> I always figured that you could make them optical - make them spring
>>> >> loaded, and have them break a beam of light going to a photo
>>> >> interrupter when they get stepped on - so nothing mechanical gets any
>>> >> unnecessary stress on it. That should last forever.
>>> >>
>>> >> But I'm sure someone knows an easier solution.
>>> >>
>>> >> -Taylor
>>> >>
>>> >>
>>> >>
>>> >> On Tue, Jan 18, 2011 at 3:54 PM, David Kelso <david at kelso.id.au> wrote:
>>> >>> Hey all
>>> >>>
>>> >>> I'm looking for some large buttons that would activate when you stand
>>> >>> on them. Preferably heavy duty enough to survive burning man. Would be
>>> >>> great if they lit up too. Does anyone know where to buy such things?
>>> >>> Or even what I should be searching for? If not, any suggestions on how
>>> >>> to build something like that?
>>> >>>
>>> >>> david
>>> >>> _______________________________________________
>>> >>> Noisebridge-discuss mailing list
>>> >>> Noisebridge-discuss at lists.noisebridge.net
>>> >>> https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
>>> >>>
>>> >> _______________________________________________
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>>> >> https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
>>> >>
>>> >
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>>
>>
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