Help Request... Channel for a LED strip

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Help Request... Channel for a LED strip

boxcarmib
I've encountered a design problem that is beyond my limited geometry skills so I thought I would email the group in case there's someone who could give me some information as to how I might go about solving the problem.
I'm working with a typical LED strip which I want to provide a spiral channel for. That in itself is straightforward but leaves a vertical channel that has all the LED's facing inward. So I imagine that by angling the channel I can get the LED's to face more forward. To my intuition this would have the result that the channel would have a natural pitch or space between vertical channel layers so that the non-flexible width of the strip is not compromised and the amount of that pitch and perhaps even the radius of the spiral at any given point could be computed by the angle of the channel.
So unless I'm mistaken about the trajectory of an angled channel in a spiral, can anyone supply me with the equation for plotting the path of a helical spiral according to the angle of the strip?
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Re: Help Request... Channel for a LED strip

nophead
The equation for a helix isĀ  [r * sin(a), -r * cos(a), pitch * a / 360] where a goes through 360 for each turn.

Not sure what you mean by the angle exactly because it is on a curve and it is more usual to specify pitch. If it was unwound I think the angle would be atan(pitch / 2 * PI * r).

On Mon, 18 Nov 2019 at 18:31, Hugo Jackson <[hidden email]> wrote:
I've encountered a design problem that is beyond my limited geometry skills so I thought I would email the group in case there's someone who could give me some information as to how I might go about solving the problem.
I'm working with a typical LED strip which I want to provide a spiral channel for. That in itself is straightforward but leaves a vertical channel that has all the LED's facing inward. So I imagine that by angling the channel I can get the LED's to face more forward. To my intuition this would have the result that the channel would have a natural pitch or space between vertical channel layers so that the non-flexible width of the strip is not compromised and the amount of that pitch and perhaps even the radius of the spiral at any given point could be computed by the angle of the channel.
So unless I'm mistaken about the trajectory of an angled channel in a spiral, can anyone supply me with the equation for plotting the path of a helical spiral according to the angle of the strip?
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Re: Help Request... Channel for a LED strip

Parkinbot
In reply to this post by boxcarmib
Your verbal specifiation is not very precise. Better make a hand drawing to
show what you mean. I read your request that you basically need a spiral
made from a wire with a rectangled shape being pitched. That means something
like this:

<http://forum.openscad.org/file/t887/pitched_spiral.png>

To produce it, you can download my " springs and spiralmaker
<https://www.thingiverse.com/thing:3252637>  " project, which I just
modified to also accept a pitch parameter.

The code to generate the shown pitched spring would be:

use <springs.scad>
spring(R=100, windings=5, w=5, h=10, pitch=25);

Please read the thingiverse project carefully and note that the spiral
cannot/maynot self-intersect. To get a closed channel with the spiral as
inner threading you can try to difference it from an appropriate ring:

difference()
{
  $fn = 60;
  cylinder(r=120, h = 150, center = true);
  cylinder(r=102, h = 151, center = true);
  spring(R=100, windings = 5, w=10, h=10, pitch = -25);
}








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