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Aaton LTR external frequency input (milliframe controllers etc)


aapo lettinen
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Hi!
I have a LTR7 here which I want to make a external controller for (something similar to the Milliframe Controller) . I am totally capable of doing this external controller by adapting my existing designs for the job, but the the real issue is:

What is the pinout of the 9-pin connector on the LTR body I have, is it standard pin order for all camera models and what are the exact pin outs and what kind of signal to feed to them?

It would be great to have some kind of official documentation about this to ensure that I don't burn anything when doing tests. (I am capable of making new crystal sync electronics for the LTR if burning them accidentally but I would totally hate doing that because the camera works perfectly in its original condition and making new electronics would waste lots and lots of time and money)

So... is there any official, absolutely reliable documentation about that 9-pin I-O connector which I could use when designing the controller for my camera? I know Tobin made controllers for these and I think there were Aaton ones too, so it has to be standardized in at least SOME way...

51370858375_b0d7a80ddb_h.jpg

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I went down that rabbit hole two months ago for my new video tap. The connector 'Tiny Tim' was made by WPI, then by Amphenol, and now you can find some rare spare stock for 10$ a piece for the female socket.

EDIT: yes, it's the same connector on the LTR as on my XTR Prod

5656454545.JPG.08e540137ac37d572fb4f88b6b4e337d.JPG

Edited by David Sekanina
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i got the quote from them:

https://componentonline.com/product/299-12634/223-1609

 

don't know if they have the counterpart plug though.

concerning if the changed the pin outs from model to model, best ask Charles Pickel, otherwise the pin out function is documented in the user manual of the XTR Prod

Edited by David Sekanina
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I found this on the XTR manual, wondering if the LTR is different but the ltr I have has lots of add-on modifications which were not originally available so I would imagine at least some of the pins could be the same (I believe the XTR was already out when the LTR was modified)

52186184703_553c1f704e_o.png

Probing the signals works for output pins from the camera but it does not work for input pins because the signal is coming from the accessory and not the camera body...

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  • 1 month later...

Looking at the LTR manual, it seems that port is used by a couple different accessories-a video assist camera or the 'atelen'.

The description of the latter states it "delivers an external master frequency signal derived from a video signal, or pilotone, to the camera."

I could be completely missing it but the connector pinout is not documented in the LTR manual. If the XTR uses the same pinout then based on the mention of 'external master frequency derived from pilotone' it seems the camera can be controlled by an analog frequency signal and if it's that 2400Hz then it seems it may be 2400Hz=24fps

The best thing to do if nobody knows would be to make an adapter cable for between the atelen and the camera and check the signals on the cable to see what signals are where and what is sending what, if you can find an atelen.

If it is just an analog frequency signal then that'd be fairly easy to generate with some pretty good frame stability for very cheap, so there is some good news there possibly.

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yes the pinout is not in the original LTR manual as I guess the accessory connector was a later add on to the design and was not available yet when the manual was written.

Probing signals would be very easy to do with an oscilloscope, I could do it in 5 mins to figure out the exact needed signal coming from the Atelen accessory and could then perfectly emulate it in couple of hours without any issues...

the issue is that I don't have any Atelens and I don't even know anyone having one which could be borrowed and tested. I can easily generate very accurate 2400Hz or any other frequency from my own crystal sync boards but the needed signal level is more of an issue as it is impossible to know without documentation or a working Atelen example and wrong signal level may burn camera electronics even if the pinout would be right as there is no quarantee there is any safety measures in place inside the camera as the camera bodies vary hugely in terms of their customization level and versions.

typically this type of speed reference signals tends to be 'digital' square wave at some of the standard voltage levels which in older systems may be for example 10V and in newer systems 5v or sometimes even 3.3v is pretty typical. Wrong pinout would be an issue and feeding too much voltage on the input pin would be too as there is no quarantee there is any safety measures in place to protect from over voltage. undervoltage would mostly just make it work very unreliably or not work at all but should not break anything instantly. My guess is it could be either 5v or 10v level as the 3.3v logic level was not common back then. The camera is so old that 10v was typical in similar era cameras but no way to know without having the Atelen on hand  😮

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I did a little more digging and it seems media logic made a crystal speed control that had a cable for the aaton. I found an LTR package with the control after some browsing. Apart from one for sale on it's own I can't find anything else, but it would appear at least that there are some options other than the Atelen for speed control. AZ Spectrum says their one speed control will work for the LTR and the 16SR.

So far that's lead to a dead end of someone here in another thread trying to figure out what their 16SR wanted as a signal. I'll keep digging in the hopes I can find something, as I'm of the mind this should be documented given how hard original accessories are to find for older cameras.

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By my experience the camera manufacturers kept most of the design specs secret and only let very few carefully selected partner companies to have any kind of information how the accessory ports work and in case of newer equipment, how the digital data lines were used for controlling the camera and what kind of protocol would be needed and how it could be emulated.

I actually asked Arri about the newer digital control protocol for SR cameras last year and they did not want to disclose the information even after all these years for my company not having long enough history of developing camera accessories. So it is really only possible to find out the specs if one happens to find a friendly service technician who would want to tell how it works... otherwise one just needs lots of luck and the working original camera and accessory to try to probe what kind of signals go back and forth between them, eventually hopefully figuring out how to emulate the most important functions of that external controller.

It is after all these years when the secrecy about the camera designs and control methods really starts to bite back. It was probably a very good idea back then 30 or 40 years ago to keep everything secret but nowadays when there is very few people around having any information about those secrets and all the original documentation is seemingly burned, buried and forgotten it is pretty difficult to keep the old cameras running in the future and it is possible that entirely new electronics need to be made for them at some point because no one just knows anymore how the original worked for it being so big of a secret for so many years 😕

Losing documentation of electronic systems if a very, very bad issue and it can happen on any project even nowadays. In case of old movie cameras, it is actually very rare that someone would be able to repair the original electronics if something goes wrong with them and in most cases the camera needs either completely new control electronics OR it is just put to storage and forgotten there forever. the CP16R is the only movie camera I know of where the user is given at least some kind of documentation of the actual circuit boards and components. With all the other cameras it is just "contact our head electronics engineer who died 40 years ago if you happen to have any issue with your camera" 😮

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Holy Crap, I apparently never throw anything out !

I had one of those "wait... I might have something.. " moments, and I dug around in some old project files, and in a folder marked "Aaton" I found a paper printout of part of an email conversation I had with Clive Tobin 21 freaking years ago about Aaton sync.

To be an FX camera guy is to be a technical packrat.

I don't know the exact question I was asking, but IIRC, I was in Australia working on the Matrix sequels and I wanted to use a couple of LTR's as 2nd-angle witness cameras for some effects we were shooting on VistaVision plates. I think. 

 

Tobin001.jpg

Edited by Steve Switaj
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Also, I found one of those weird, WPI 9-pin connectors made out of unobtanium in a box of... well.. weird connectors.

If anybody has a need for it, they can have it for what I paid, which was probably about $30, plus postage to wherever it's going.

DM me.

WPI 9 pin.jpg

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On 8/5/2022 at 6:49 AM, Steve Switaj said:

Holy Crap, I apparently never throw anything out !

I had one of those "wait... I might have something.. " moments, and I dug around in some old project files, and in a folder marked "Aaton" I found a paper printout of part of an email conversation I had with Clive Tobin 21 freaking years ago about Aaton sync.

To be an FX camera guy is to be a technical packrat.

I don't know the exact question I was asking, but IIRC, I was in Australia working on the Matrix sequels and I wanted to use a couple of LTR's as 2nd-angle witness cameras for some effects we were shooting on VistaVision plates. I think. 

 

Tobin001.jpg

Thank you a lot, this definitely helped! 

I think it would be possible for me to test it sometime later this year with the LTR if I get it working correctly. I would love to have other sync framerates on it than 25 and I can make external speed generators relatively easily so will probably adapt one of my external control designs for LTR use later on 🙂

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  • 5 weeks later...

I will make some tests with the external speed input in October or November. If it seems to work correctly, it would not be too much work for me to modify my 45-speed "VariCr External Control" controller (originally designed for CP16R) to work with the LTR as I would just need to change the firmware a little bit and make a adapter cable so that it can be connected to the LTR. I would target the price range of about 350usd+shipping for the controller and the cable.

if anyone would be interested in this option, let me know beforehand as I have tons of different projects in development and I will prioritize them based on how much interest they gain and how likely it is that I will get my own money back from any individual project 🙂

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