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Specifically, I am trying to detect whether an umbilical boom from fueling a rocket has retracted, and other miscellaneous tasks (vents raised / retracted).

I have done some research and have found ways to determine the displacement of an object - is that actually to be the best way to do it? For example, say the boom needs to retract 10 ft. In that case, if the sensor finds a displacement of 10 ft +- 10%, then MovementStatus = True.

Or is there some form of light sensor / position sensor that just detects the fact that the object is in the position where it's supposed to be, in an efficient way?

boardbite
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Tim
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2 Answers2

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I would keep it simple and use a microswitch to detect the end position:

enter image description here

and connect it to your Vcc. Add a pull-down resistor to ground, and you get a logic level indicating the status: high = switch closed, low = switch open.

stevenvh
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    and.......... ? – markrages Sep 14 '12 at 17:13
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    @markrages - building up suspense :-) – stevenvh Sep 14 '12 at 17:42
  • classic stevenvh, never mind. – Standard Sandun Sep 14 '12 at 18:53
  • Wow, they're big, aren't they? ;-) – m.Alin Sep 15 '12 at 19:20
  • @m.alin - haha, you remembered that! :-) Actually, these don't show *that* much bigger than real size on my 21" monitor. The "micro" seems to be compared to those huge industrial switches, often 10 cm or so. Maybe you're looking at them on a 250 cm TV screen? :-) *( BTW, I went to have a look at that post again, but as I remembered it the original image was *way* bigger, but I didn't find that in the edit history :-/ ??)* – stevenvh Sep 16 '12 at 06:19
  • Any image in real size is too big for me :-) Yep, the original image was definitely bigger. Maybe I replaced the original image too quick and it didn't count as a separate edit. – m.Alin Sep 16 '12 at 12:54
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Usually microswitches are used to verify that a piece of equipment has reached a particular position. They come in many configurations; the actuator can be a simple spring leaf, or it might have additional features such as a roller that drops into a detent on a moving part.

Dave Tweed
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