Totally green question

Projects General Guidance
1

Hi All,

before I start, know that I have no experience specifically with Arduino yet but am willing to learn and tinker. I do have some understanding and experience with the mechanical side of things and a basic of understanding of programming.

I have a project in mind but with the limited knowledge I have, I'm not sure if I'm biting off way more than I can chew and would like some advice on feasibility and likely level of technical expertise required to make it work.

I do quite a bit of macro videography but any handheld movement at that scale becomes really nasty and bumpy so I'm limited to static shots. In some hand held shots I can even see my heartbeat shaking the camera.

I would like to make a movement rig so that I can create some nice smooth pan/tilt/slide/orbit shots etc moves controlled remotely to eliminate the nasty bumps and shakes.

What I am aiming for is smooth footage that looks like it's been taken from a drone or with a gimbal, but for macro.

Initially I thought to start with a bare CNC bed with the camera suspended where the head would be, moving in first person view with an external monitor.

The 3 steppers would be run through an UNO directly from a 3 axis joystick (X,Y and rotation around Z). Which would work I think. However, once I rotate the camera, the axes would no longer be pure X and Y. For example, if the camera was rotated 45deg right, I would expect that a left movement of the stick to produce a left movement from the point of view of the camera, which would require equal movement in both the pure XY axes. Trigonometry. I hope I explained that well enough.

That is my stage 1. I would really like to know if I and the electronics are going to be capable of producing what I see in my head before I set out on a frustrating journey without hope of success. If I could realize stage 1 I would be happy to push the button on the project and get started.

My stage 2 would be to have a couple of standard presets. Perhaps at the press of a button perform a 100 deg arc from the current coordinates around the fixed focal point over 10 seconds. Focal distance would be a constant distance from the axes' central point.

Also, rotation on X (tilt) would be useful and to a lesser extent rotation on Y (roll).

Stage 3 would be moving automatically smoothly through a set of XYZ waypoints/keyframes over a set interval, useful for either real time or time-lapse scale interval.

Any and all advice welcome. Please let me know if I'm being realistic and call me out if I'm not. Or if there is a better way to realize the idea, I'm all ears.

TYIA

Mat

2

I think the success of what you want will depend more on the quality of the mechanical system than on the microcontroller.

Stepper motors are very convenient for coordinated movement as in a CNC milling machine or a 3D printer. However stepper motors move in steps and I think you will need to experiment to see if the stepping is visible in your films. Using a high level of micro-stepping will minimise the roughness. There may also be audible noise - I don't know if that matters.

The alternative is to use very low geared DC motors. They should give smooth movement but identifying the exact location is not as easy. Some form of external feedback system will be required. If the distances are not great then the linear digital readouts (DRO) (similar to a digital calipers) that are used with machine tools might be an option as they will give an absolute position. A rotary encoder on the output of the gearbox is another option, but they only report relative movements.

I'm thinking of this type of geared DC motors. They are widely available - often much cheaper than Pololu - and seem to me to be very well made and nearly silent. And because of the low gearing they have a lot of torque for their size.

Whatever type of motor you choose you will need a suitable stepper motor driver or DC motor driver between the Arduino and the motor.

...R
Stepper Motor Basics
Simple Stepper Code

3

Thanks Robin,

That all makes sense to me. I would rather use steppers if at all possible just to embed both the movement and spatial awareness in the one system.

Your advice on the micro stepping is solid. I think I'll build a simple single axis slider and get an appropriate stepper and geared DC motor for it and try each out. With camera attached I should be able to see what will work.

Noise doesnt bother me, I usually add a different soundtrack anyway.

4

Wormboy:
I think I'll build a simple single axis slider and get an appropriate stepper and geared DC motor for it and try each out. With camera attached I should be able to see what will work.

That sounds very sensible. A lot of newbies here expect to be told what will work without the need for any experiments.

I agree that stepper motors would be more convenient.

If you could sync the steps (or, more accurately, the interval between steps) with the camera shutter even crude stepping would probably not be noticeable. But I have no idea how to do that.

...R

5

Thanks again,

With a bit of searching there seems to be a few geared DC options with integrated rotary encoders that should do the job nicely and still be useful again on my phase 2 and 3 goals.

6

Wormboy:
With a bit of searching there seems to be a few geared DC options with integrated rotary encoders that should do the job nicely and still be useful again on my phase 2 and 3 goals.

Just be aware that reading a rotary encoder that produces a lot of pulses per second will use up a lot of the Arduino's processing capacity.

...R