Accomplishments
This week I ran some preliminary real-world tests to determine whether basic projectile motion equations could accurately predict where a ping pong ball would land, given two very close time frames and positions. These tests were ran using our smartphones, slow-mo recording (240fps), a whiteboard gridded out with a marker for translating the ball’s position in the video to position in real life. We restricted the axes to only x and y, tossing the ball parallel to the whiteboard. While my calculations turned out to be off by 10s of centimeters, by adapting to a python algorithm that takes air resistance into account, that error came down to less than 7cm. An important takeaway is that because the timeframe between ball frames is so low, getting accurate ball positions is CRITICAL. A difference of a centimeter can make a massive difference in computed initial velocities.
Progress
Besides the testing, I whipped up a spreadsheet for our bill of materials for the project, and added the materials required for the xy-plotting gantry. The total cost came to around ~$150, and could come down further if there are materials already at CMU we can take advantage of.