In our group we were assigned to make a video on who we could detect another objects speed. We used a distance sensor and coded it to detect the object, then we used a rapid relay ball and rolled it towards the robot. We recorded the distance of the ball in our TEAM notebook and calculated the speed. Please let us know what we could do to improve. Thank you!
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I’m assuming you made lots of measurements? Did you graph them all out so you can not only show the speed but the acceleration / deceleration?
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Adding on, a sticker added to the ball or the radius of the ball could be used to find how fast the ball is spinning.
Sticker method: Each time the sticker comes around is a Revolution of the ball.
Radius method: Calculate the circumference of the ball’s [largest] cross-section, use your [already mentioned] calculation of the ball’s speed and divide it by the ball’s circumference (be mindful of units) to get rotations per. unit (like seconds).
And yes… this data will change as a function of time so you can graph it (as per. Foster’s suggestion).
I thought the distance sensor natively measure object speed? If you don’t want to use that, definitely take multiple readings for the most accurate speed/average speed. If you just take two position readings total per ball you are assuming constant velocity, which is not always true. You can get the acceleration/decel too. Easiest is integration, but you can also just look at the slope of the graphed speeds.
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Organize it into a graph inside of excel to caculate it and make it more neat
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How would you find the speed tho
I think this project sounds fun! I would like to ask, how many times did you test the robot? And if you did , did you document it in a chart?
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You take one reading of distance, wait a certain amount of time, take another reading. Divide distance/time. 
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