Sunday, May 26, 2013

Building The Ultimate DIY Slider | The Plan

For those who don't know, a Slider is a contraption used in film industry to move the camera in a linear direction, its a bit different from camera dolly, if you see movies carefully, you may have noticed a scene where the actor is saying a dialogue and the camera is slowly moving sideways or forward, this is achieved by using a Slider, it adds the extra dynamics to the shot. To know more, watch this funny video below by Film Riot;

The best professional ready to use sliders out there are very expensive and mostly made in US, and for people like me who live in India, importing is a pain due to 30% custom duty and heavy shipping charges.
So this year I have set forth a goal to build the Ultimate Do-It-Yourself Motorized Slider using my Mechanical background and learn some electronics on the way with guidance from a friend, Abishai Dmello, who is into electronics. Basically I am aiming at one slider that has all the following features;
  • Manual control when needed - No matter how much automated\motorized it is, it should always allow me to operate it manually using my hands to move the slider.
  • Simulation of hand movement and speed - Whatever the motorization mechanism is, it should be able to move the slider fast enough for real time videos and should be able to ramp the speed instead of constant speed.
  • Vertical operation - The mechanism should have enough torque to operate when the rail of Slider is vertical in position
  • Light in weight - The Slider should have optimum weight so it can be transported easily.
  • Proper length - The length of slider must be long enough to achieve desired linear movement, and short enough to fit easily during travelling.
  • Timelapse Friendly - The mechanism should be able to simulate move-shoot-move motion to use it efficiently for capturing holy grail timelapses.

So to achieve the above features in a single slider, I decided to have the following provisions made in my design;
Digital Manual Speed Controller
  • For manual control when needed - a simple solution to detach the driving mechanism from the slider carriage.
  • For simulation of hand movement and speed - use a 12V DC Gear Motor that gives 60RPM Speed and control it using Servo City's - Digital Manual Speed Controller.
  • For vertical operation - the operating torque of motor should be 12.5kg-cm or higher, in my case, as the gear I will be using will not be greater than 5kg.
  • For light in weight - i will be using aluminium based material.
  • For proper length - it seems that 3ft of slider length is sufficient to satisfy that.
  • DollyShield DIY Kit
  • For Timelapse Friendly - i will be using Dynamic Perception's - DollyShield DIY Kit with Arduino Board to control the motor for move-shoot-move motion.
Yesterday I received the first few key items that I need to build this Slider system, they all are available in US only, I had ordered them a month back, and a friend's father who works in US brought them to me on the way back to India for vacation. The items are as follows;

Dynamic Perceptions's DollyShield DIY Kit:

As you can see above, the kit basically consists the stripped components of Dynamic Perception's MX2 Controller without the Arduino Board, which we have to buy separately. The whole kit is a DIY, you will have to solder all the components to the PCB and then attach a Arduino Dueminalove or Uno Rev 3 to complete the controller.

The controller gives the following features;
  • Two- or Four-Axis Motion Control - The MX2 supports two DC brushed motor axes directly using the built-in motor drivers.  An additional two axes of motion in pan and tilt can be added simply by hooking up a Merlin Telescope Head to the MX2.

  • Integrated Camera Control - Hook any camera with a supported remote cable up to the MX2 and start shooting motion-integrated timelapse videos right away.  No need for additional intervalometers or other electronics to synchronize the camera with the motion.  Control every aspect of the exposure, including auto-focus and exposure on-camera or controlled by the MX2.

  • Advanced Motion Capabilities - The MX2 can run all axes of motion in both continuous and interleaved (shoot-move-shoot) modes.  Complete control of the output motion including ramping/feathering in the output video and delayed lead-ins are possible with the MX2.
  • Power-Saving Features - Auto-dim the screen, or disable it completely on a timer to reduce power draw when shooting in the field.  Advanced motor control reduces power draw during continuous motion moves.
  • Auxiliary Inputs / Outputs - Interact with your environment, integrate with other systems and expand your capabilities.  The MX2 is ready to take inputs and make changes to the program on the fly based on triggers from external sources.  Switches, relays, and more can be used in conjunction with the MX2.

  • Open-Source - The MX2 is built around open-source electronics and firmware.  Hack it, mod it, change the code, add new features - it's yours: you are free to experiment.

Servo City's Digital Manual Speed Controller (DMSC):

This device is a ready to use Speed Controller for precisely controlling a DC Gear Motor's speed in both directions (Forward\Reverse). It has a potentiometer that enables manual ramping of speed, so we can move the camera at constant speeds as well as stop\start the movement smoothly\gradually\variably . It can operate any DC Motor that requires 6-16 Volts of DC Voltage to operate, the power  can be supplied through two ways, tamiya connectors or DC Barrel Power Jack.

Tekkeon myPower ALL Plus MP3450i Battery (5-19V):

Well its obvious that I need something that can power the device that I am building, so I chose this portable battery, its just perfect for my purpose as it provides 5-19 Volts of DC Voltage, its a Lithium Battery that means less recharging time and more battery backup. It has two outputs, one that gives the desired voltage from 5-19V and another which is a USB port that provides 5V for charging cellphones and other devices.
So if I am not using this battery for Slider, I can use it to power many of my other devices like Tascam DR-60D, Cellphones, Laptops etc.

To put the whole idea of this DIY project in simple words, I am building a motorized slider to control the linear movement of camera for both Real Time Videos as well as Timelapse Sequences, using Servo City's DMSC for variable speed in continuous motion and Dynamic Perceptions DollyShield DIY Kit for interleaved motion (move-shoot-move) and power the whole set up using the Tekkeon MP3450i portable battery.

In next article I will cover the mechanical design of the Slider, which Rail and Carriage Assembly I will be buying, and other list of items that I need to piece the whole project. [*Edit: Click here to read the next article in this series.]

Till then stay stoned!


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