Terrible diagram 1

I’m trying to figure out how long to make A and B here if I have linear actuator of length C (extended = 2C) in order to tilt my panels from completely horizontal to vertical so they avoid wind and shed snow respectively when I run up the actuator to the extremes respectively based on sensor input.

Is there a simple formula I can use to plug the length of whatever actuator I settle on to figure A and B out? I know it will have to be a certain minimum and maximum size to work properly and might have to experiment to get an idea of what works in the end, but I’d like a reasonable start point to purchase an appropriate actuator.

I’ve googled around and decided I’m not smart enough to even come up with the right search criteria, let alone figure this out myself since it’s been 35 years since I’ve used anything except the most basic trig.

This isn’t really homework except for the fact that I’m trying to make my home work right.

Edit: seems like if I select A=.75C and solve for B at horizontal, then it always works out. No idea why, but the couple examples I try seem to agree.

  • echutaa@programming.dev
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    5 months ago

    Ok I understand better what you’re trying to do, this is a pretty basic trig problem there are a ton of triangle calculators out there that will give you a good idea of the lengths you want. This site even has some explanations of how sine and cosine can be used to find missing sides and angles. Also just a note, any triangle can be split to create 2 right angle triangles, it’s not the ideal way to solve these problems but can help simplify some concepts to make things easier to understand.

    • ikidd@lemmy.worldOP
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      5 months ago

      OK, so there’s some way to use the idea that at retracted, b^2 = a^2 + c^2 and at extended, 2C = A + B.

      Since I have a 78" long panel I was going to hinge about 1/3 of the way from the top, it seems like a 60" tall post would be a reasonable height to work from. Just plugging random numbers in, if I have an LA of 24" and randomly select A=18, at horizontal B=30 and at vertical those add up to 2C=48.

      It seems like if I make A=.75C and figure out B with pythagorean, then the second equation works out as well, ie: C=18 and A=13.5, then B=22.5 and it comes out right at 2C=36. Same with C=16 and A=12, B=20 and 12+20=32.

      No clue how I make the above equations prove that, but seems to work.

      Thanks for reviving that part of my brain. Now I can go back to killing those brain cells with alcohol.