A Tripod-Mountable Motorized 2-Axis GoPro/Smartphone Slider for $20
Introduction: A Tripod-Mountable Motorized 2-Axis GoPro/Smartphone Slider for $20
Ever wanted to do those clips where the camera pans smoothly around an object? Well, using a gimbal or manual camera dolly can give some impressing results, but they require either a real calm hand or a well-prepared surface to roll on. In addition, the movement might by limited to one linear direction – the camera travels along the object, but it does not keep the object in the center of interest all the time.
So, in many cases a multi-axis slider with electronic motion control is need for moving and rotating the camera synchronously. There are many professional, expensive devices for this purpose, and there are already a lot of great DIY approaches out there, based on different budgets and skills.
The configuration presented here aims at providing a really cheap, yet usable and easy-to-make construction which can be placed on a single tripod and powered by standard 5V/USB power banks. The solution is light and portable – making it optimal for outdoor use. The components of the entire setup cost around $20 – including the motors and electronics! And: It differs from many other solutions in its user interface, because you can precisely set the start and end positions of the camera movement.
Supplies
* 2x Square Aluminum Tube 1 m x 15 mm x 15 mm (hollow, smooth finish)
* 1x 1,4" Nut (UNC, for tripod mount)
* 1x 2GT Timing Belt (2 m, open, any rubber or plastic will do)
* 1x 2GT Timing (Driving) Pulley (20 teeth, 5 mm boring for 6 mm belt width)
* 1x 2GT Idler (Driven) Pulley (20 Teeth, 5 mm boring for 6 mm belt width)
* 1x Arduino-based Stepper Control with two 28BYJ-48 Stepper Motors, see description here
* 1x M3x8 Grub Screw (or regular M3x8 screw), 4x M3x8...10 Screw, 5x M3 Nut
* 8x M4x10 Screw, 4x M4x16 Screw, 2x M4x40 Screw, 14x M4 Nut
* 7x M5x30 Screw,7x M5 Nut
Optional:
* 2x "Tight Fit" Plastic Double Spur Gear (30 + 10 teeth, module 0.5, 2 mm bore, usually called "30102A")
* 1x "Lose" Plastic Double Spur Gear (30 + 10 teeth, module 0.5, 2 mm bore, usually called "30102B")
* 1x Steel Shaft (length: ~10 cm, diameter: 2 mm or 3 mm, depending on the gearbox design, see below)
* 2x Small Rubber Band
* 1x 3D Printer with Approx. 250g Filament (PLA, PETG or ABS)
Step 1: Assemble the Motor Control Box
The process of assembling and programming the control device is described in a separate tutorial. The components of the entire "box" should cost less than $10, including the motors. 98
The design is based on very cheap 28BYJ-48 motors and their ULN2003 "driver" boards.
The Arduino code given within the instructable mentioned above sets calls the both connected motors "M1" and "M2". It handles both motors as rotary drives, so everything is measured in degrees ("deg").
The code provided here does more or less exactly the same as before, but - as a small enhancement - it renames the both motors to "F" (for feed drive) and "R" (for rotary drive). Based on this definition it shows the linear position of the slider in mm instead of deg, and the speed drive is given in mm/min instead of deg/min, so the feed drive position and speed relate directly to the slide. This is only a small improvement, but it is very useful for estimating the travel distance (and speed) of the slider.
The calculations from degrees to linear units are based on the assumption that you are using the pulleys that are proposed in the part list (2GT with 20 teeth). If you change to other pulleys, please modify the scale factor at the beginning of the code. For 2GT pulleys, MM_PER_ROT must be 2 x number_of_teeth. If you like to have imperial units (i.e. inch) instead, just divide this value by 2.54, search for all appearances of the sub-string "mm" and substitute it by "in." or "inch". 7