High Speed Outdoor Photography

High speed photography is generally carried out in a dark room with dedicated equipment (controlled remote flash for example)...
The instructable proposed here enables to make high speed photography outside (and enjoy the sun!), in less than 2 hours with some generic DIY basic tools.

The principle is the following :

1. A marble is dropped in a repeatable way.
2. During its fall, it gets in front of a distance sensor that sends a signal to an Arduino card.
3. After a tuned delay, Arduino triggers a servomotor rotation that pushes the camera button (as we would do with a finger).

By ensuring the same dropping conditions from one photo to another, we can tune the delay to capture the best moment.

Step 1: Equipment

For this experiment, we need

• A bowl of water, milk or other liquid to drop things into it;
• A marble
• An distance sensor (the one used here)
• An Arduino card and an alimentation system (the one used here)
• A servomotor (the one used here)
• A camera!
• Option (useful stuff): helping hand, crocodile clips, wires, tape, etc.

Step 2: Make a Repeatable Drop System

The idea is to have a gutter-like path from which the marble is dropped always in the same way (for example, from the same point with null velocity).
In order to reach a sufficient height from which to drop the marble, I piled up stuff and mounted the path on it. Be sure it is sufficiently stable to remain static from one drop to another.

Step 3: Make the Falling Marble Detection System

Just under the path, the marble should be detected to trigger the camera adequately. The detection sensor should be mounted accordingly with its range to detect the marble. I used crocodile clips to fasten mine.

Step 4: Dispose and Set the Camera

The camera should be disposed so that the splash is perceived. To avoid blur, use the highest shutter speed allowed by the camera (a sunny afternoon is far better than the night to have a correct exposure) and a manual focusing (else the autofocus may lead to unexpected delay and may focus on bad areas). For information on camera settings, click here.
Focus manually on the bowl.

Step 5: Make the Camera Triggering System

Once in place, tie the camera on the support (double side tape for example). Then, dispose the servomotor so that its moving part gets in contact with the camera. Attach firmly the servomotor (I used a helping hand well screwed and crocodile clips for this).
Download the HighSpeedOutdoorPhoto.ino file and link the sensor and the servomotor to the Arduino card according to the instructions. Upload the HighSpeedOutdoorPhoto.ino file to the Arduino card.

Check that the marble fall correctly triggers the camera; be sure that the servomotor gets back in the same position after triggering and that the camera does not move during the operation.

Step 6: Tune the Delay

Refine the proposed delay (25 ms) so that the camera captures the best moment.

Enjoy !

PS : Thanks to the Deroubaix family for their warm welcome !