Measuring speed of falling object

Projects General Guidance
23

I helped a kid do a similar but different falling-object project: (Early, with a IBM PC, Parallel Port driving IR LED and IR Phototransistor)

  • 4 inch plastic drainage pipe about 6 feet long, bottom end 2 feet from floor, pillow on floor.

  • Drop different-length 2x4 inch wood blocks from the top

  • I-R Beam sees leading and trailing edge of falling block

  • Do the math and display how long the block is.

It was correct and repeatable to about 1/4 inch as I recall.

Doubt I could resurrect the Turbo Pascal code after 20+ years...