DIY Motorised Video Camera Slider

[Kristian Yates]

I've recently seen some great videos on YouTube made using a DIY Video Camera slider system for around £10. The idea is that the video camera can be manually pulled slowly along a set of rails alongside what you are filming, achieving a beautifully smooth tracking shot.

I'm building my own version of this, which has a camera mounted to a device similar to a roller-skate. The advantage of this, is that the axels can be adjusted independently, to allow it to curve for other shots if I wish. With the wheels straight, it will be pulled down a piece of plastic trunking or square drainpipe cut in half alongside the things I'll be filming.

The £10 versions on YouTube have you pull the camera down the track manually, which is quite smooth, but I want it smoother than that, and I also want more control over speed so I can do a really fast shot from left to right if I want to.

So I'm looking to put a motor on the end which will pull the roller-skate (Weight is 1.5KG with camera mounted on top). I also need some sort of speed control, and it must be battery powered.

The though had crossed my mind to pull a toy car apart, but I'd like to learn how to do it.

So I'm looking for ideas on power, a motor big enough to pull the camera along the rail, and potentiometer or speed controller system. Control at slow speeds are a main priority.

I've mocked up a diagram and look forward to any help you guys can give.

Cheers

Kristian

 

[Kristian Yates]

Minor update: Now decided to mount the motor on one of the roller-skate wheels to act as a drive wheel. This means it can roam free in any direction. Found a little about geared motors running at around 40RPM. Thinking that some kind of speed controller hooked to this could be excellent. With an extended cord, I could walk around with it an be in full control of speed.

 

[BioniC187]

Welcome

Well, let's see. The weight of your roller skate isn't much of a problem - the rolling friction and inertia when static are not going to be 15N because you have wheels. It'll be far less than 15N.

For the motor, look for a geared 9V motor 90RPM. Something like that, doesn't have to be exact. Do you have a rough idea of the max speed you wish to achieve? You will need to have a pulley made for the motor, the diameter of the pulley will be based on the Max RPM of the motor and the max speed you want the camera to move at - roughly

You want good control at low speeds, so you need drive the motor using Pulse Width Modulation(PWM). Using a pot directly on the motor will not render good results at low speeds. For the PWM driver, its really easy using a 555 timer with other small parts.

You can google PWM 555 timer and you will get many results.

 

[BioniC187]

Oh i started typing before you posted. Well, as long as mounting the motor won't be a problem, go for it. Since you want the motor to move in either direction, you should use an H bridge IC that will give you this control.

It's really easy to set up as well

 

[Kristian Yates]

Nice one, Bionic! I've been trying to get this info for a couple of hours now. Still considering the belt / winch idea.

Thinking about the new idea of mounting it and driving one of the wheels. I can make something to bracket it on without much trouble. But I've just been speaking to my Dad, who thinks the power required to drive one of the wheels would be huge, and the power requirements pretty immense. We've be talking windscreen wiper motors and everything!

I thought it would be much less, and I'm wondering if a geared 9V motor 90RPM is enough to get over initial inertia and drive 1.5KG (plus battery).

Do you think that's enough, and is the battery weight not going to weigh it down?

 

[Kristian Yates]

On a mad day, the speed might get up to around 1 foot per second, but would usually being running between a 5 feet per minute and 20 feet per minute

 

[BioniC187]

I don't think it would be huge. To be sure you can test it if you want.

Attach some fishing line to one end of the wheels with the camera on it. Place your wheels on a table, and let the other end of the line be tied to an object of known mass. Let this mass hang over the edge of the table. So now if it moves, that means that the mass of the object is what is required to move your camera. We can use that to choose an appropriate motor.

Oh, keep reducing the mass so you get a minimum amount so we can establish a minimum force required

 

[Kristian Yates]

The roller dolly arrives on Friday, so I'll test it then. Cheers BioniC!

 

[BioniC187]

Alright, keep us posted. Cheers