# Mobile Limelight Hood Angle Calculation

Hello all!

I just returned from a long night’s work at our buildsite, and I am a little bugged. We have a limelight mounted to the mobile part of our hood, opposed to a fixed position. We did this recently, and I already like it much more; however, my distance calculations seem to be incredibly less accurate now.

I understand that if I am using a mobile limelight, all I have to do is try to bring the tY and tX to zero. Although true, I also need to account for hood’s angle based off of how far I am. The code I am using to generate this distance is as follows:

``````        return (98.25 - self.llHeight) / (math.tan(math.radians(llAngle + self.getY())))
``````

`llAngle` is the variable that is the physical angle of the hood relative to the ground. I can assure you this is accurate.

I would appreciate it if anyone who had any ideas on how I could account for the difference in my hood angle and shooter speed based off of how far I am, other than an actual, calculated distance would share them; or, if someone could explain what might be causing this distance inaccuracy.

P.S., I am considering area of the target. Is this a good idea?

I assume you are adjusting the llAngle based off a sensor, are you also adjusting the self.llHeight I assume that would be changing as the hood goes up and down.

Depending on the tilt of the hood and the distance you are away the limelight height value being a few inches off could make a significant enough difference.

I definitely understand what you mean, and I don’t have a way for monitoring the height. I could try to estimate a linear fit however i don’t think this is causing too much error.

Using the values we used this season goal height of 81.25", LL height of 23.0" and fixed camera tilt of 32 degrees if you take a target with a y of -10 degrees offset the distance would end up being ~144.1" if you change the LL height to be 25.0" for example that would change it to ~139.2" if the target is even further away with a -20 degree offset the difference would be around 8". Not sure what you classify as significant and obviously it changes depending on the height and tilt of your camera in general.

Yeah, although this is true. The difference is about half of what the expected value should be. I have some ideas which I’ll try tonight.

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