chocochunk

I am continuing the development for the “Caddy” video rig with the addition of the popular Arduino board. As I have documented previously on my blog, the Caddy is a video camera rig that drives on a 2″ track to tow a helium blimp outfitted with a 13-ounce Sony camera.

The Arduino, an open source electronics developers board, has a usb port and software for flashing code. Very accessible and well supported by its fans, it should be a perfect addition to the Caddy since it supports both analog and digital I/O and there are code libraries available to make use of servos, which are small yet accurate motors with lots of torque. In this application I will make use of an electronic speed control similar to a servo. Once the code is worked out so that my sensor and speed controls work together correctly, the main chip can then be removed from the Arduino and placed in a more streamlined circuit at a fraction of the cost. And then the Arduino will be ready for my next development project.

The video Caddy tends to slow down a bit in the turns of the track due to the wheels cinching. With a microprocessor on board, I will be able to instruct the motor’s speed control to increase if there is a loss of speed relative to the throttle on my radio controller. Since I am towing the blimp with three 6-pound fishing lines, it will be very critical to have a smooth-moving “train” with plenty of mass. To keep the speed steady, I will print out some sheets with equally spaced black lines and glue them to my track. To keep these calibration lines accurate, I will use Adobe Illustrator; with its large workspace I will be able to make accurate lines out to the 9′ radius of the Caddy track. I have some optical sensors that are designed with this application in mind. The sensor contains two readers in one case. By timing the difference between the light and dark lines, the Arduino will determine the velocity at which the Caddy is moving. And the Arduino will sit between the radio and the speed control, as seen in this graphic.