[Noisebridge-discuss] Step-on buttons

T t at of.net
Wed Jan 19 14:59:21 PST 2011


For fatigue, spring steel.

Or better yet: capacitative sensor.  No moving parts minimizes both
deformation and fatigue.

Two plates separated by insulator are a capacitor.

Foot on plate -> capacitance changes.

As does the resonant frequency of any oscillator that uses that capacitor.

Frequency change means foot is present.

Best Regards.



On Wed, Jan 19, 2011 at 13:17, Taylor Alexander <tlalexander at gmail.com> wrote:
> Actually, creep is deformation due to constant stress over a long
> term, and metals aren't really subject to creep at room temperatures -
> it's mostly plastics. If you hang a weight from a piece of plastic, it
> will stretch over time, even if the weight is much less than the yield
> strength of the plastic.
>
> Fatigue is deformation due to repeated stress, where creep is
> deformation due to constant stress. Neither will really be an issue
> for this - the likely problem would be regular ol' yield failure - IE
> someone just bends the thing from stepping on it too hard - if the
> metal isn't thick enough.
> -Taylor
>
> On Wed, Jan 19, 2011 at 12:06 PM, Sean Cusack <sean.p.cusack at gmail.com> wrote:
>> The metal term you are looking for is "creep" :), and no - I haven't got any
>> of this yet over 2-3 years of moderate use.
>>
>> I think I used 18ga. galvanized steel. Its tricky to solder - use an acid
>> core solder and some extra flux if you need it - should make your life much
>> easier. The weather stripping needs to be along the outside of the sheets
>> since the middle is where all the bending action happens. You can also sub
>> in foam board if you want to save even more cash, but then you do need to
>> cut it into strips which can get annoying. The panels are roughly 12" x 12"
>> squares.
>>
>> I put acrylic tops on the panels that shielded a decal so they would look
>> pretty. It should be easy enough to implement this as an LED diffuser or
>> something if you want them to light up!
>> Sean
>> 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
>>> >> >>> _______________________________________________
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>>> >> >>> Noisebridge-discuss at lists.noisebridge.net
>>> >> >>> https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
>>> >> >>>
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>>> >> >>
>>> >> >
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>>> >
>>
>>
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