I shot my 180 fps airsoft gun and my camera got only 1frame of it. My 270 fps gun the camera did not see.
this is not to be judged in the launch it competition, its for the many people that could use this to improve their instructables
video on step 5
using some gestimation (fired sling shot and half way pulled back) i estimated the speed of my sling shot at 72 miles per hour (at full speed the camera didnt see any thing so i just multiplied by 2 i know its not accurate but it dosent have to be.)
the pics below:
it spent 4 frames on the lined part of board. after crunching the numbers the 14 gram projectile averaged 7.5fps (this is one of 5 tests) it was fired from my 7 gram torsion spring catapult
Step 1: Gather materials
a camera (at least 20 frames per second)
flat cardboard ( around 2 feet long 1 foot tall)
ruler (as long as cardboard is tall)
tape or thick marker (tape: blue scotch painters tape 1inch think)
calculator (recommended not needed)
Step 2: Board set up
do the same for opposite side.
then draw a strait line across.
if using tape, tape right between the lines.
if using marker color between lines
if your board has little bit left over just put "spots" so you know its not a full inch