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Ghettobarney Trick Member
Joined: 21 Dec 2006 Location: Failing Pandy |
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ChilliumBromide Trick Member
Joined: 16 Jun 2006 Location: Beaverton, OR |
1. Posted: Wed Feb 21, 2007 11:25 pm Post subject: |
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You might want to tweak that so that it's got 2 tubes pushing down the metal about 2 inches apart from each other. That way, it pushes down the centre more than the panel has to move.
Also, there's a sensor thread somewhere, if you want to dig it up, cool. If not, I probably will tomorrow, and then we can link it from one of the relevant stickies for reference. _________________
I used to be active here lol |
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Edible Bondage Tape Trick Member
Joined: 26 Jan 2002 Location: Kerri |
2. Posted: Thu Feb 22, 2007 5:35 am Post subject: |
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really why dont people just use micro switches
these dending metal designs will eventually fail when the metal stresses or warps _________________
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ChilliumBromide Trick Member
Joined: 16 Jun 2006 Location: Beaverton, OR |
3. Posted: Thu Feb 22, 2007 4:30 pm Post subject: |
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Exclusive Bonus Track wrote: | really why dont people just use micro switches
these dending metal designs will eventually fail when the metal stresses or warps | Less than 26ga steel should be fine. Thin aluminum or 30ga steel will crack though. _________________
I used to be active here lol |
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devout Trick Member
Joined: 15 Dec 2006 Location: the atl |
4. Posted: Thu Feb 22, 2007 6:12 pm Post subject: |
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Wikipedia says it well: "Some materials (e.g., some steel and titanium alloys) exhibit an endurance limit or fatigue limit, a limit below which repeated stress does not induce failure, theoretically, for an infinite number of cycles of load. Most other non-ferrous metals (e.g., aluminium and copper alloys) exhibit no such limit and even small stresses will eventually cause failure." - http://en.wikipedia.org/wiki/Metal_fatigue
And on the topic of microswitches:
"They are very common due to their low cost and extreme durability, typically greater than 1 million cycles and up to 10 million cycles for heavy duty models. This durability is a natural consequence of the design. Internally a stiff metal strip must be bent to activate the switch." - http://en.wikipedia.org/wiki/Microswitch
How your stress compares to the endurance limit will vary for each design, but in any case I think when sensors break its usually because the weatherstripping or other squishy materials wear out... those wont last nearly as long as any metal. |
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Edible Bondage Tape Trick Member
Joined: 26 Jan 2002 Location: Kerri |
5. Posted: Thu Feb 22, 2007 11:39 pm Post subject: |
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another reason for the micro switch no need for weather stripping or other crap _________________
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nfok3 Basic Member
Joined: 13 Feb 2007
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6. Posted: Sun Feb 25, 2007 10:41 pm Post subject: |
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microswitches sound like a good idea, but how would your panel return to its original position? Would the springs in the switches be able to push it back up? |
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Edible Bondage Tape Trick Member
Joined: 26 Jan 2002 Location: Kerri |
7. Posted: Mon Feb 26, 2007 12:29 am Post subject: |
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micro switches come in more than just the style inside your super advantage you know
you can get a compact micro switch that could puch a kia car if you needed it _________________
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devout Trick Member
Joined: 15 Dec 2006 Location: the atl |
8. Posted: Mon Feb 26, 2007 8:03 am Post subject: |
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nfok3 wrote: | microswitches sound like a good idea, but how would your panel return to its original position? Would the springs in the switches be able to push it back up? |
They may or may not be a good idea... when you buy them it will list how much force it takes to push the switch, so just pick a value that is greater than (weight of your arrow panel) divided by (number of switches per panel). Problems that you might run into are that they only travel about a millimeter or so... you need to position them pretty precisely, so plan ahead as to how you can mount them precisely. (They make ones with long lever arms, but I dont think these could support the weight of a thick acrylic step) They also might give your pad a clicky sound/feel, which you might not like. And most cost in the 2-3 dollar range, though they go down to about 50 cents a piece.
If youre cool with all that, then they are probably the way to go, as you can be pretty sure they'll work every time for a very long time. |
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