Introduction: Marathon Man - Director's Cut
Did you ever wish to make a movie but don't have the budget of George Lucas? Well, here's what you can do with little money in your pocket.
Note: the vintage flickering in the video is caused by the interference of the camera taking the movie and the actual production speed which differ slightly from the 1/30 second picture interval. Live at home it's brilliant HDTV, of course ;-)
Copyright notice: the original clapperboard image was taken from Wikipedia since I was too lazy to re-draw it in Inkscape,
Step 1: Build the Stage
Let's start with the stage for your actors. It's a simple round wooden platform driven by a tiny motor. I cut the stage from 3 mm plywood with a center punch a little bit smaller than the axis of the DC motor. For the lighting I used some LEDs from an old lamp, but a single white LED will do as well.
Step 2: Scene Play
The next thing to do is to create the scene play. Print the above template and place the pictures in the 10 rects. If you are an artist, draw them by hand. Or google for "flip board examples" and use one of them (like I did). The template has 10 picture frames. If your film has more or less you can easily adapt the template to hold the right amount of single pictures.
Now glue the film to the paper circle and place it on the plywood scene board. A little neodymium magnet in the center will hold it firmly to the stage.
Your actors will then act by being spun around and flashed at some 1/30 second rate. Well tuned with the director's command they appear to act.
Step 3: Stage Direction
The electronics needed to control the film set is very simple. It uses two output pins (one of them for PWM) and one optional analog input.
The Arduino controls a transistor with PWM that drives the DC motor. The potentiometer in the above schematics is optional for controlling the motor speed. The motor must rotate at rather low speed which eventually is hard to set. It might be necessary to power up at higher force and then slow down to the desired speed. Pin 9 is taken for the motor speed control. It can be set this way with analogWrite in a range from 0 to 255. My motor had the right speed at around 30.
Pin 13 drives the LED directly with no resistor since the Arduino will limit the current to some 20 mA which is save. Even if not, the LED is operated with short pulses and could take even a higher current.
The Arduino uses Serial to communicate with the PC from which it receives commands to set motor and flash speed. Those commands are formed from a single control character ('L' for LED and 'M' for motor) and a number from 0 to 255. The flash speed is mapped to a range from 1/10 to 1/50 second. The motor speed is mapped to the range 25 to 75.
Setting the right motor and flash speed needs a bit training. Easy peasy for a director-to-be. The attached Processing sketch connects to your Arduino via Serial. You need to adapt the right index to address the correct port. When it opens, it shows a small frame which is virtually divided in an upper (light) and lower (motor) part. The red slide can be set to any position inside the frame by clicking. The respective number value (left equals 0 and right 255) will be sent to the Arduino.
Alternatively to this software control the firmware has prepared a potentiometer control for the motor. It's easy to add a 2nd potentiometer for the flash control.
Step 4: Action!
Now setup your stage similar to the above picture. The motor should be fixed to the ground (mine had a flat stand already and I just needed to fix the cables a bit). Place the paper film on the stage and fix it with the magnet. The LED should be directed towards the front of the turning film wheel. Tune the motor and the flash lights - and enjoy your film!
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