Clocking the velocity of falling objects

Place FunKey Super in LightGate Mode (A/I), with the IR reflection sensor attached to port G, and an alligator clip connection W to ground.  As the object passes the sensor, it triggers and then stops a microsecond internal clock on the FunKey.  The FunKey sends back the elapsed time as a text string via the USB port, which you can input into or read in any word processor.  Alternatively, the data can be passed to a simple Scratch or Javascript program.

This program also works to plot velocities for the classic "picket fence" object as it falls past the sensor


On this web page, you can determine the momentary speed of any falling object at a given distance from its dropped point:

 

https://www.angio.net/personal/climb/speed

You can use a ball but a cylinder works better.  A soup can or a small dowel of 3/4 inch or small length of pvc pipe works very well.  Let it just fall off the table edge and pass in front of the sensor.  Just measure down from table top to sensor position to get the fall distance.  Then take the width of the cylinder and divide by the elapsed time as reported by the sensor via the USB port.