What do you get if you take two physicists who like photography and give them three long nights to tinker?
Answer: you find yourself using an Arduino http://arduino.cc , a relay shield for Arduino http://www.seeedstudio.com/depot/Relay-shield-V20-p-1376.html?cPath=39_42, an electromagnet, a DSLR, a flash, some aluminum plates, some wood, a glass jug, water, milk with food coloring, coins, strawberries. After plenty of tinkering, it works somewhat along:
- The relayshield is connected to the electromagnet and the flash
- The electromagned is moving a plate of aluminum over a second one, both have holes, after the magnet fires the holes are aligned
- A coin (or strawberry) is sitting on the aluminum plate
- Firing the magnet starts the descent of the coin
- After a configurable number of milliseconds (let’s call it X), the flash fires and ‘freezes’ the motion as the object hits a jar of water (or milk)
- The camera is set to 3 seconds, it is dark
It turns out the setup is surprisingly ‘stable’ in the sense that once you have figured out the right value of X, you consistently get the same moment of the coin (strawberry) dropping in water (milk). We’ll look at the physics involved in this posting.
For now here are the pictures taken at night #2 and #3 – pick your favorite 🙂