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dunnie
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# Posted: 26 Oct 2016 08:34am
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Hello all. Long time lurker, first time poster. I have gotten a lot of good info here. Hope I can explain this well enough. I am in the process of building a 2 axis solar panel mount. I am building from scratch and need some geometry help. I need to calculate degree of angle on a lever based on a position from the fulcrum (12 inches) where I will attach an actuator and move the lever 6 inches in one direction. I need to calculate the degrees of movement on the lever. Is there a formula for this?
Thanks.
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RichInTheUSA
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# Posted: 26 Oct 2016 08:56am
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Draw it out for us... That's what Euclid would do.
How long is the lever, and what is the height of the panel. What is the angle of the panel to the platform (roof?) ?
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Cisco
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# Posted: 26 Oct 2016 09:26am
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I'm a High school geometry teacher. Be glad to help. i think i understand but a pic would help. give me a bit. I'll be back
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Cisco
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# Posted: 26 Oct 2016 09:35am
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So the 6 inch movement will be in an arc. so we figure circumfernce.
12 in radius times 2 times Pi = 75.36 inches in circumference if we had a full circle.
you want to go 6 inches out of 75.36 or 6/75.36 or 7.9% ish
a full circle is 360 degrees so 7.9 % of 360 is 28.666 degrees.
so if i undestand your set up correctly then 6 inch movement with a 12 inch radius will move approx 28.6 repeating degrees
Im in between classes so in a hurry. will come back to check y arithmetic and make sure i understood your question
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Cisco
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# Posted: 26 Oct 2016 09:39am
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take circumference in inches ...2 x pi x radius of a complete circle. Find percentage of movement based on inches wanting to move.
then take same percentage of complete circle based on 360 degrees.
or do a proportion part over whole equals part over whole
6 in / 75.36 in = x/360 cross multiply
2160 = 75.36x divide by 75.36
28.6 degrees = x
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Cisco
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# Posted: 26 Oct 2016 09:42am - Edited by: Cisco
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Now if you want a 6 inches in vertical movement rather than an arc then Trigonometry gets involved.
I can do that too but it'll be harder and take longer. I'm gonna wait to do that until I hear back from you.
I am confident the 6" in arc and 6" in vertical will be very close to the same in degrees.
So how exact do we need to be?
EDIT- BTW, I teach math. Typing and grammar are not a strong suit.
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Cisco
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# Posted: 26 Oct 2016 09:56am
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Ok so lets go ahead and do the trig
imagine its a right triangle we are finding the degree opposite the 90 degree angle
one side ( horizontal) is 12 inches. the other side ( vertical) is 6 Inches ( your movement)
So we use Inverse Tangent of X( our angle) = opp/adj
InvTan x = 6/12
inv Tan X = .5
X= 26.5 degrees
so if you want the 6 inches to follow an arc its 28.6 degrees
if you want the 6 inches to be vertical its 26.5 degrees
hope this helps. and if i have completely misunderstood the question let me know and i'll come back I'm subscribed to the thread
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dunnie
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# Posted: 26 Oct 2016 12:02pm
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I hop this helps if it gets uploaded correctly. It is Axis.bmp
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dunnie
Member
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# Posted: 26 Oct 2016 12:06pm
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What I am doing is designing this on paper first then building it. I need to get the actuators placed correctly and get the various parts to move enough degrees to get sun angle from East to West and tilt from North to South. I just can't picture in my head how far from the fulcrum do I need to start my lift to get a desired degree of movement. Hope that helps to understand what I am looking for.
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Cisco
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# Posted: 26 Oct 2016 12:07pm
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Quoting: dunnie I hop this helps if it gets uploaded correctly. It is Axis.bmp Attached file: Axis.bmp Â
Yes. it is as I imagined. That is movement in an arc. and will be 28.6 degrees based on your measurments
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Cisco
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# Posted: 26 Oct 2016 12:18pm
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Quoting: dunnie What I am doing is designing this on paper first then building it. I need to get the actuators placed correctly and get the various parts to move enough degrees to get sun angle from East to West and tilt from North to South. I just can't picture in my head how far from the fulcrum do I need to start my lift to get a desired degree of movement. Hope that helps to understand what I am looking for.
so do you know your desired degree of movement?
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Cisco
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# Posted: 26 Oct 2016 12:22pm
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If your actuator is at the end of the 12 inches and pushes up 6" vertically thereby raising the end of the 12 " inches 6" above parallel to the horizon then the end of the 12" will have moved 26.5 degrees
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dunnie
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# Posted: 26 Oct 2016 12:37pm
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Thanks Cisco. This helps a bunch. I can put this into an excel spread sheet and use it over on different ways.
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Cisco
Member
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# Posted: 26 Oct 2016 12:50pm
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cool. glad to help. Like I said, I am subscribed to this thread so if I can help further just hit me up.
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dunnie
Member
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# Posted: 27 Oct 2016 10:03am
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Cisco, based on the information (and lesson) you gave me, I put this excel formula together (C2=360*(B2/(A2*2*PI()))). Seems to work well.
Quoting: Cisco so do you know your desired degree of movement?
This is the next step. I need to determine the amount of degrees I need to swing the panels from E to W and from N to S based on my geographical location.
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Cisco
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# Posted: 27 Oct 2016 10:09am
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Quoting: dunnie Cisco, based on the information (and lesson) you gave me, I put this excel formula together (C2=360*(B2/(A2*2*PI()))). Seems to work well.
Very Cool! I use excel but I'm not versed enough to do the more complex formulas.
That formula will measure the movement at the end of your lever in degrees along an arc. Think of a circle. Your fulcrum is at the center and the end of the lever follows the path of the circle.
so in the above explanation its the 28-ish degree one. Keep us updated!
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dunnie
Member
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# Posted: 27 Oct 2016 10:13am
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Will do and thanks again.
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neckless
Member
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# Posted: 28 Nov 2016 08:29am
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on my solar set up i went and found a old tv dish stand ....lol they are everywhere got it free...its all done just add actuator its done.....
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