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Creating an intervalometer


GeorgeSelinsky

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Hi folks,

 

I wanted to create my own intervalometer. I saw the website http://www.saunalahti.fi/~animato/ which is very interesting, but it doesn't go into enough detail. I was wondering if anyone had any suggestions for starting points. I just need it to go one shutter speed really, because the purpose of the device will be to shoot off a CRT screen. I don't want to pay (nor have the money to) $1500 for a commercial unit.

 

To me it seems rather simple, get a motor, attach it to the 1:1 inching knob of my Arri II, and make sure the exposure is about one half a second so my computer monitor doesn't flicker. I have a lot of video footage for my film and I want to be able to do the kinescope myself. I will sit there and click the thing manually, because I have to advance the frames manually on the computer.

 

One of my main questions is how strong of a motor do I need? Can I use one of those 12 volt Radio Shack jobs? Also, any ideas of how to couple the motor pin to the Arri's inching knob would be appreciated.

 

- G.

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You could just rent a Norris or other unit for a fraction of the price.

 

Your Arri 2c is not the ideal camera for this work. With no registration pin, the image "floats" around in the frame. This is generally not an issue for regular shooting (it becomes painfully obvious when you burn over titles), but if you shot frame by frame the motion could become very irregular and really jump all over the place in a distracting if not completely unusable manner.

 

You might want to contact a place like Metropolis Film Labs to work out a low buget solution for your situation.

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I thought this was only an issue with multiple pass work like with blue screen and whatnot. I have done some animation on a Bolex which wasn't pin registered and I didn't seem to have any problems with it. Is the Arri II more prone to this problem?

 

- G.

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It's just that in 24fps work the float will actually be a float that drifts around on the screen, while in single frame it can pop back and forth in extremes, which can be visually very disturbing. I know that animators greatly value pin-registered movements for just this reason, even when doing single-pass work. Again, I'm not an expert on this and would suggest you ask someone like Jack at Metropolis. You might be completely okay doing this--don't know.

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  • Premium Member

Hi,

 

If I had to do something like this, I'd use a radio control servo and either build a one-shot ratchet mechanism or use a sail-winch servo which can do continuous rotation.

 

On the other hand, I would probably do this because I have no problem building electronics to drive PWM servos. Others may have less geek credability!

 

Phil

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  • 7 months later...
Guest NCSProducts
Hi folks,

I wanted to create my own intervalometer. I saw the website http://www.saunalahti.fi/~animato/ which is very interesting, but it doesn't go into enough detail. I was wondering if anyone had any suggestions for starting points. I just need it to go one shutter speed really, because the purpose of the device will be to shoot off a CRT screen. I don't want to pay (nor have the money to) $1500 for a commercial unit.

- G.

 

I can understand not wanting to spend the $$ for a commercial unit. I mean, just using the Revolution Motor for single-frame use, and not using all the incredible time lapse features, would be a shame. :(

 

Here's how to make a quick 'n' easy single-frame motor for your Arri II.

 

Step 1: get a servo and modify it for continous rotation.

http://www.acroname.com/robotics/info/idea...continuous.html

I would get rid of the electronics and just power the motor directly.

 

Step 2: stick a 5mm hub on it.

http://www.servocity.com/html/servo_shaft_adaptors.html

The inching shaft is 5mm diameter.

 

Tape the servo to the camera. Don't worry, the servo is light, and the drive is low-torque. Use a pushbutton to power the motor, or rig up a little microswitch like on the animato site.

 

Shazam! All done. :rolleyes:

 

- Dom

http://www.intervalometers.com

Edited by NCSProducts
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Guest Sean McVeigh

I built one a few months ago using a rather large stepper motor coupled directly to the inching shaft. A few FETs and a microcontroller to program the exposure time, frame rate, etc. Probably cost about $50. Haven't had a chance to use it yet though as the project I built it for evaporated.

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  • 5 weeks later...
Guest Bruce Frye

The Arri 2C is capable of steadiness at single frame rate even what could be termed rock steady. This is a fact as I have done it many many times. Again, this is not hearsay or speculation this is fact. I have used many non pingegistered cameras to do animation, time lapse and all types of single frame work. You are right it is multiple pass work that requires pin reg. The only problem with the 2C and other mirror shutter (non focalplane) cameras is the light that leaks around the shutter and fogs the film with non-image forming light during long intervals, that is, the interval during which you are not exposing the film. This problem is eliminated with a capping shutter, an external auxilluary shutter mounted in front of the lens. The other solution is turn off the light source during the interval. Can you work in the dark and have your computer screen go dark during the interval

 

Building a single frame manually actuated single frame drive is not hard to do. No electronic controls are neccessary. You need 3 switches: roller, momentary NO, and a simple spst; a disc on your motor that is eccentric at one point aprox. 1/8", a small 12 or 24 volt gear motor that runs at approx. 1,2,3 or 4 RPS. and a flexible coupling to connect the motor to the inching knob shaft and a foot or so of 18 gauge stranded wire. This stuff is available all over the place: All Electronics, H&R, C&H Surplus, Apex electronics etc. You must machine a mount to hold the motor in position on your camer. this could be a piece of extruded "L" shaped aluminum. Do you have any facility with the following: a drill, a hacksaw and a metal file?

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