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Custom crystal motors for Cameflex

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Hi you all ūüôā¬†

You may have noticed that I have lots of different camera motor related projects going on.... A forum member asked help on another thread for DIY converting a Cameflex rheostat motor for single speed 25fps crystal sync but he chose to attempt brushless motor route instead because it is much simpler to do. 

I however already checked the encoder placement possibilities briefly for him and much later though maybe I could attempt this conversion by myself (even though I initially thought it would be unnecessary for me because I will use 16mm cameras for sync sound. But then I realised that I will still want to use the Cameflex for MOS night shooting under streetlights because it has 180¬į shutter possibility. And so it could be useful for me if the camera would have the 24 and 25fps crystal speeds because it is much easier to haul the rheostat motor and small external box around than to use the large 230v mains operated sync motor and inverter just to be able to shoot under flickering lights.) ¬†

How many of you actually shoot with a Cameflex nowadays? 

Would anyone need this type of conversion and how many would actually order it if it were available? 



It is generally not practical to modify only a total of one single motor or two motors for one's own use. There is significant amount of work on designing the speed control system and it needs to be extensively tested as well. And it takes lots of time and resources. So I think this type of modification would be useful and fully possible but I would only be interested attempting it if there would be at least four or five people who would order the conversion. I would also need to know beforehand what is the maximum price for the work per motor and what would be the most needed features, only then it would be possible to design the system in the first place.

I am talking about converting this style of "Type 24" motor which I happen to have two working ones so I could use one of them for tests if there is enough interest for this mod. 




I quickly drafted that the system could be something like this: 

- an external control box where the control electronics are. The speed sensor is installed in the motor itself. Some kind of cable connects the two together. 

- real crystal sync with at least two crystal speeds.  Plus a simple variable speed function which allows speed ramps. So I would add at least two speeds and the varispeed function.

- more crystal speeds are possible, it may raise the price though. A rotary switch would be the easiest way to select the speed with minimal parts so I would prefer using it for speed selecting.

- some kind of display is possible. it is useful with the variable speed if wanting to set a custom MOS speed. Display functions take lots of work to code so it will add to the price of the system.

- with current technology it is possible to generate weird off-standard crystal sync frequencies easily. There is some limitations depending on what exact frequency is needed (how accurately it is mathematically possible to divide the original crystal frequency to the desired final frequency) . But any frequencies can usually be divided with at least two decimal accuracy, often better.

- Battery type and voltage??  I would personally use my own camera with 12v batteries after the conversion so I would add voltage regulation in any case. So it would be possible to design a system which runs on V-lock batteries or similar style batteries. So a 4-pin XLR at least but what more? a v-lock adapter to the back of the control box?


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It seems that I will try this project this Autumn. No one here has been interested in this type of system so I will probably just do it for my own camera and when getting something ready I will post the results here :) 

I am planning making it according to the following specs if it seems practical. If I am doing the system just for my own camera it is easy to do anything I want :)

- from 11 to 20 preset crystal speeds, OR a adjustable crystal speed generator with small increments so that I can set any crystal speed from the specified fps range.

- a good display to see the settings

- works on 12V batteries via standard 4-pin XLR 

- control electronics are in a small external aluminium box which has attachment points to be mounted on the side or on the top of the camera. Box is connected to the actual motor via cable which transfers the power and the encoder signals.

- maybe some kind of onboard battery which attaches to the side of the control box. Needs to be Lithium so will need to see if it's practical or not to make.

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Very interested to see your progress !

i am still shooting with my CM3 from time to time!

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1 hour ago, Jo Kamimura said:

Very interested to see your progress !

i am still shooting with my CM3 from time to time!

Nice to hear! I will test various approaches with the Type24 motor when I got time for it. 

One of the ideas was to try to integrate the control system in the existing space inside the motor. There is very little space for it but I think it could be done. We'll see later :) 

Originally I was going to collect couple of motors off eBay and adapt them all, then if the modified motors would be good I could have sold the readily modified ones so that people would have had the possibility to purchase a ready to use motor instead of sending their own one in for modification which could take a long time. There was two or three nice Cameflex motors on eBay for affordable price. But someone purchased them all and have not seen more of them since so I will just modify one of my own motors and forget stocking ready-to-use motors for other users¬†ūüėě

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I drafted a simple crystal sync system for the Type24 motor. The system is installed in place of the original rheostat control and would not add much bulk to the overall size of the motor. It uses the original start-stop switch of the motor. Single speed 25fps or 24fps would be the easiest to do and it would use the original battery voltage of about 6 to 8 volts. No variable speed, just a single stable sync speed.  Expected accuracy of the speed stabilization would be about 0.01fps.

Would anyone be interested in this type of modification? I think it would be much more useful than the external box system because it is more handy and does not add much weight or size to the motor, at most just makes the motor body a centimetre or two longer. I have one spare motor which I could modify and sell if someone is interested (I think 550usd for the modified motor + shipping).

Estimated cost of the modification: about 350usd + shipping + possible customs costs if you send your own motor here for the modification. 

Please let me know asap if you are interested in this type of crystal sync possibility for the Eclair Cameflex.

I have limited access to my metal lathe due to the corona crisis and will need to direct my limited development funding to the most promising projects, so any project which does not seem to be time critical will be delayed at least couple of months, even a year. So I will need to know how many would want to order this type of modification so that I can direct resources to the designing work.

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it would of course be possible to add multiple speeds to this type of all-integrated compact motor but it will make it a little bit more expensive and it will make the upper part of the motor a little longer because then I would need to fit one additional circuit board and the selector switches there which takes quite a lot of space. Probably around 3cm longer motor with 3 or 4 selectable crystal speeds when the single speed version could probably made without altering the motor dimensions at all. 

It might be possible to add a external signal input for the single-speed motor so that the external sync signal would just override the internal sync and no switches would be needed on the motor itself. then an external box could be used for additional speeds.

Let me know what you think. Would a single speed and very compact system be better, or would one definitely need the additional speeds and they should be integrated even if it would make the motor more expensive?

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No one has been interested in this Eclair modification so I will postpone it about 6 months or so. Thus being able to concentrate on the projects which have had more interest. 

Today I checked the Eclair Cameflex Type24 motor again and it is fully possible to build the crystal sync electronics inside the motor in the place of the old rheostat. 

The planned specs are the following: 

- the motor can function with the original 6 to 8v power source. Maybe the cable connector needs to be changed. I would like the motor to use the original start-stop switch so I would want to keep the connector the same if in any way possible. 

- the speed sensor attached inside the gearbox. Some custom mechanical parts need to be manufactured.

- 4 crystal speeds built-in. The top part of the motor would be a little longer than with the original Rheostat top. 

- it may be necessary to run a thin external cable from the gearbox to the motor top. Inner cables are very challenging to fit to the motors and would make them much more difficult to modify. Partially this is due to the old 70 years old motors having rusted screws and stuff which makes it very time consuming to disassemble them completely. So it will probably be a thin 4-pole wire running from the gearbox to the top part of the motor. 

- estimated price of the 4 crystal speeds update to the Type24 motor: about 600 usd + shipping + possible customs and tax. 

As I said, this project has not gained any interest so far.  so I will postpone the project at least 6 months and will concentrate on the other projects in the meantime. 

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I noticed that some collector is hoarding all the Cameflex motors from eBay and this means that there will soon be more camera bodies than there will be motors available. 


I will still do the crystal modification to the Type24 motor at some point. But that will probably be single-speed 25fps modification I will use only for my own shooting. No one was interested in the Type24 modification anyway so there is no point of doing it for others I think :D 


ANYWAY.  Because there will soon be more cameras available than there is motors, I think it would be possible to manufacture a completely new motor which fits Cameflex cameras and has multi-speed crystal sync control. A completely new motor with control box which has a display and, say, from 10 to 20 selectable speeds?  

I have a control box setup under construction which can be used for this system. Lots of display options, footage counter and so on. Connected to the motor via a short cable so that you can mount the control box to a point where you can easily see the display when operating the camera.

Let me know what you think. Completely new Crystal sync Cameflex motor which has at least 10 crystal speeds, a display etc. and the price will be well under 1K ?  Anyone would need this type of system?   I could make one in couple of months if I would know someone would order it .

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