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aapo lettinen

Is there a demand for custom sync sound motors?

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I became interested in microcontrollers a while ago and I am considering a DIY sync sound motor for my Kinor 2m camera. I also have other cameras which could use a stable speed motor (for example my 35mm Soyuz-US3N camera and the rheostat motored Konvas 1KCP. This is because there is no available motors of any kind for Soyuz and the rheostat Konvas never had any sync motors made originally) . 

I started with the 16mm Kinor motor last month and I'm refining the analog control electronics and fine tuning the code now. I was just thinking, is there lots of people out there who could use a customisable sync sound motor on their camera and if so, which exact camera models would be the most in demand?

If there seems to be some common interests then I could take them into account when developing my own motor project and it might be easy to make custom solutions for other persons cameras as well.

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What would be the absolutely mandatory specifications for this type of motor? I am aiming for +/- 10rpm accuracy at the moment but we will see how accurate the diy solution will be when it is fine tuned for the specific motor and camera model. That 10rpm accuracy would be about 1 frame drift for every 2.5 minutes of footage shot which should be usable for sync sound uses in indie films which have relatively short takes (a minute per take for example). My current design for the Kinor16 motor will have 6 different preset speeds and it uses the original pilot tone generator just like the Olex crystal sync modification does though my design is not as sophisticated or accurate (one gets what one pays for :) the Olex motor is better and my design is cheaper). 

- what type of camera and "wild" motor would most urgently need a digital speed stabilising system like this one?

- how accurate the speed needs to be. how much it can drift to be usable? I am talking about minimum specs which would enable practical use of the system, NOT about how much would be nice to have :)

- how much it can cost, in case there seems to be so much demand that it would be doable to do for example a dozen or so of these? 

- how much the end user can assemble by themselves? is a parts kit with pre drilled circuit board enough (needs soldering and a little bit of tuning) or only fully assembled board would do?

- it is very clear from beginning that this type of product needs to be user installed to be a viable option. It would not be economical to ship cameras and motors back and forth between continents, that would ruin the whole point of this type of motor solution 

- what kind of inputs for the encoder which is attached to the motor. My current design uses the pilot tone generator signal coming from the Kinor motor but for other cameras I will use either a encoder disc or magnetic sensors for rpm feedback. 

 

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continuing the project little by little. My current specs: 

- rotary switch for selecting 6 preset speeds. The speeds are specified directly in the program code and can be changed there. 

- a LED lights up when the selected speed is reached

- simple start-stop switch (can be wired to the original start-stop switch of the camera)

- input for AC pilot tone signal with simple setup to turn the signal to square wave for frequency metering

- the fine tuning of the speed control stability needs to be done setting the values directly in the code. this has to be done for every preset speed separately if the system is installed to different type of motor. basically testing how much the motor rpm oscillates around the set speed value and then manually tuning the pwm values to stabilise the rpm

- the board contains a protected output for motor pwm signal but the power transistors actually driving the motor are separate (some motors have suitable metal surfaces which can be used as heatsinks so it is more handy to make the control board small and figure out the power electronics placement case by case

 

- will add: output for using the frequency metering signal on external devices 

- will add: operational amplifier based, adjustable sensitivity input which could use optical and magnetic sensors for motor speed monitoring. 

- a possibility: dual operational amplifier inputs, both adjustable but one for encoder input and one with rectifier circuit to use with generators

- might happen or not: a small display to read information. this requires lots more coding and I will finish everything else first before attempting this

 

If anyone is interested in the project, please add comments and suggestions here or PM me. If there is a demand for this type of custom motor control electronics we can try to figure something out and maybe even do a small production run if it seems to be economically possible 🙂

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I would definitely be interested but I imagine the price point would be pretty high to make it worth your time.

I think the NCS Revolution Sync Motor sold for around 1K, not sure if they're still being made or not.

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1 hour ago, Webster C said:

I would definitely be interested but I imagine the price point would be pretty high to make it worth your time.

I think the NCS Revolution Sync Motor sold for around 1K, not sure if they're still being made or not.

I currently own three cameras which urgently need sync motors so I am primarily making the system for them. so small scale prototyping is not that costly and I have already done most of the hard work except the actual circuit board design (have to learn to use new programs so takes some time). The price point depends on how much the board needs customization or if the design I use fits the other cameras as well. Physical size is the most limiting factor if one wants to fit the whole system inside the existing motor housing. If an external box would do, then it would be much much simpler and cheaper.

One of the factors is that the current code needs to be fine tuned per camera/motor type and the end user may need to do this by themselves. The current system is based on Arduino so the fine tuning is very easy to do but it may not be for everybody and will take some time.

what will seriously take the cost up would be: 

- shipping cameras and motors back and forth, especially from U.S (installing by me instead of the end user) . By my opinion this should be avoided unless absolutely necessary

- small physical size which is more demanding on the circuit board manufacturing technology. Larger boards can be made by me at home by simple means but very small boards will probably need to be custom made in manufacturing company which necessitates very precise designing and standardizing and a larger production run which is not economical for this kind of relatively early prototype 

- custom manufacturing mechanical parts like encoder disc fittings. this may necessitate shipping the motor back and forth

 

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Aapo, when you give tolerance at +/-10rpm, is it intended for cameras/motors with a 1 frame/rev relationship? If so that tolerance may be too great.

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37 minutes ago, aapo lettinen said:

One of the factors is that the current code needs to be fine tuned per camera/motor type and the end user may need to do this by themselves. The current system is based on Arduino so the fine tuning is very easy to do but it may not be for everybody and will take some time

what it practically means is that one needs to open the program code in Arduino IDE , locate the lines which set the PWM cycle low and high values separately for every frame rate and then manually fine tune the low and high values when comparing how stable the set speed stays when changing the values. I may do this differently in future versions so it might change. The speeds are rpm in this version (the "freqSetVal" ) :

Quote


  if (freqSetVal==360.0){    // 6fps
    pwmValueLow = 40;
    pwmValueHigh = 120; }
    
  if (freqSetVal==720.0){   // 12fps
    pwmValueLow = 65;
    pwmValueHigh = 170; }

  if (freqSetVal==1438.56){   // 23.976fps
    pwmValueLow = 110;
    pwmValueHigh = 220; }
    
  if (freqSetVal==1440.0){   // 24fps
    pwmValueLow = 110;
    pwmValueHigh = 220; }
    
  if (freqSetVal==1500.0){  // 25fps
    pwmValueLow = 130;
    pwmValueHigh = 240; }

  if (freqSetVal==1920.0){  // 32fps
    pwmValueLow = 210;
    pwmValueHigh = 250; }

  if(digitalRead(STSTOP==HIGH){
    swModeA = true;  }
 

 

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9 minutes ago, Gregg MacPherson said:

Aapo, when you give tolerance at +/-10rpm, is it intended for cameras/motors with a 1 frame/rev relationship? If so that tolerance may be too great.

at this stage I am not absolutely sure how accurate the current design can be when it is properly fine tuned. The first working prototype could maintain about 50rpm accuracy so the 10rpm is a good target for now. Part of it is that the analogue electronics are not properly tuned yet and the square wave conversion is not perfect which messes up the speed calculations a little. The Kinor motor also generates one pulse per revolution which is not optimal for this type of system. With a proper encoder with dozens of slots the speed accuracy would be much better in any case but it needs lots of testing to see how accurate it can be

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24 minutes ago, aapo lettinen said:

what it practically means is that one needs to open the program code in Arduino IDE , locate the lines which set the PWM cycle low and high values separately for every frame rate and then manually fine tune the low and high values when comparing how stable the set speed stays when changing the values. I may do this differently in future versions so it might change. The speeds are rpm in this version (the "freqSetVal" ) :

 

It would be possible to attach a potentiometer on the board which could be used for fine tuning these values. but not every one of them... maybe one or two of the speeds closest together like the 23.976, the 24.00 and the 25.00 . That would actually help 90% of the users. I will consider that option 🙂

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7 hours ago, Tyler Purcell said:

What if the camera's movement makes so much noise you can't record sync sound anyway? 

then you add a blimp housing to the camera 😎

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design specs update, added features: 

- two trimmer potentiometers to easily fine tune the PWM values on the most critical mid range speeds (these are the 23.976, 24.00 and 25.00) . The fine tuning of the system on these speeds can be done with a screwdriver and no need to touch the code at all. The other speeds still need fine tuning to be really stable, especially the low speeds where high torque is generally needed 

- I will test off-the-shelf slot-type speed sensors to speed up the prototyping process a bit and standardize a critical part. If it works correctly, then a very common eBay sensor part can be used and it does not need preamplifier which makes circuit board designing much easier and would enable the end user to assemble all the mechanical parts of the system 

- function added to the program code which enables using a encoder disc with the system very easily. Just add the slot count of the disc to the code and it should work out of the box.

 

I have more time for prototyping next month. I will probably make a dedicated test motor for this project with custom diy made encoder disc. this way it is easier to finesse the speed control functions. I will probably use a motor of 10A to 15A power draw range which also helps testing the power electronics of the system.

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Project update: more prototyping and testing the code updates I made.

- the speed selector system works correctly. I use a rotary switch with 6 position to select 6 pre-programmed speeds.

- the trimmer potentiometers for manually adjusting the PWM high and PWM low limits work correctly. I will just change one resistor to get full adjustment range.

- the analog input circuit still had some problems with Kinor motor under about 400rpm so I will redesign the circuit completely. this is a transistor setup, not the operational amplifier based system which I will assemble later. 

- the current system is based on Arduino Micro because I will want to reserve the I2C bus in case I will add the display sometime later. The selection of the Micro is beneficial in every other way but there is no cheap Chinese knockoffs of it as far as I have seen. I will use genuine Arduinos anyway so that is not a problem for me :) 

Still a lot of work to do but I will surely finish the project this year. 

Some prototype testing I did yesterday for the speed selector switch. I am using the serial monitor and laptop to tune the code and monitor the behavior of the system especially when checking the function of the analog input circuit. The small grey box next to the camera motor is a Chinese tachometer I use for monitoring the motor rpm during the tests, it uses the other winding on the pilot tone generator and is thus completely separate from the Arduino setup. 

49568353708_9be18fe078_b.jpg49569079707_7a1abae346_b.jpg49569079572_0dbb61de17_b.jpg 

 

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more testing and testing. I updated the input and output electronics completely which made a dramatic improvement to the speed calculations accuracy.

the output circuit is pretty OK but I cannot get full speeds with 12V battery so have to do more drawing later on. 

In the meantime, I changed the code a little just to test what kind of RPM range the trimmer potentiometers can stabilize. I set the lowest rpm preset to 360 rpm and the next were 540, 720, 780, 790 and 920 rpm. (I can't get over 1100 rpm with 12v battery before the output circuit is updated so the 920 was pretty good maximum setpoint)

When I tuned the rpm to be as stable as possible at 720 then the 780 was pretty accurate (about 778 - 782 ) as well as the 790 rpm was only off by couple of rpm. The 920 rpm was varying between 910 and 924 . The 540 was about 550 and much more unstable whereas the 360 was very unstable oscillating at around 400 rpm.

It seemed that the 360 rpm (6fps framerate) was too optimistic for this particular motor and I have to change the minimum framerates considerably up. So I will probably change the framerate presets to be 12fps (720rpm) , 16fps (960rpm) , 23.976fps (1438.56rpm) , 24.00fps (1400rpm) , 25.00fps (1500rpm) and 32fps (1920rpm).

From this test I would say that one could do with one set of trimmer potentiometers if concentrating on the mid range of speeds and can tolerate the high speeds being a little off from target but still stable. However the low speeds are problematic in this regard and I would recommend changing them in the code. Additionally there was not much torque at the very low speeds so it might be wise to just concentrate on the mid range for now or leave the very low speeds completely off and only including the speeds of over about 600 rpm which can be tuned correctly and have enough torque. 

The great news is that when tuned to 720 rpm the system was able to keep it easily around -4 / +3  rpm on the target and it seemed it could probably be tuned further to about 2 or 3 rpm accuracy especially if the power supply is regulated. Checking the serial data from the Arduino's speed calculations I think that the main reason for this type of rpm variation (it would already be enough stability for sync sound with this kind of much better than 10rpm accuracy) is that there is just not enough pulses for the Arduino to count from because the Kinor motor gives only one pulse per revolution. This means that with the encoder disc the rpm stability would be much much better and I would expect the speed to be at least 1 rpm accurate or in one decimal range when the setup is tuned. 

 

 

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It's great to know you are working on this. I have been working on some simple modifications and accessories to make cameras more usable and I'm glad to know that there is people in other parts of the world working on creating this kind of stuff, specially complicated stuff like  a crystal syn motor and with the technology that we have today like 3D printers and options to create inexpensive prototypes I hope you can make this happen.

I have an Eclair NPR that needs a motor and I'm sure a lot of people with NPRs and ACLs would be interested as well. In my opinion 24 and 25fps are the ones that need to be crystal sync. I don't do a lot of slow mo, so for me 48, 64 or 75fps wild  but close would be great.

I don't know about the part of final users putting stuff together. I can do a lot of things, but I have no idea how to use an Arduino and I think most people would not be able to do it themselves, but you may find a partner in America and make it work that way.

Keep up the good work, I'll be reading your updates.

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17 hours ago, Ruben Arce said:

It's great to know you are working on this. I have been working on some simple modifications and accessories to make cameras more usable and I'm glad to know that there is people in other parts of the world working on creating this kind of stuff, specially complicated stuff like  a crystal syn motor and with the technology that we have today like 3D printers and options to create inexpensive prototypes I hope you can make this happen.

I have an Eclair NPR that needs a motor and I'm sure a lot of people with NPRs and ACLs would be interested as well. In my opinion 24 and 25fps are the ones that need to be crystal sync. I don't do a lot of slow mo, so for me 48, 64 or 75fps wild  but close would be great.

I don't know about the part of final users putting stuff together. I can do a lot of things, but I have no idea how to use an Arduino and I think most people would not be able to do it themselves, but you may find a partner in America and make it work that way.

Keep up the good work, I'll be reading your updates.

Thanks 😊 

this is exactly the type of input I am gathering to figure out how to advance with the project and what the end user's needs would be. 

Another person already asked me about the Eclair motors as well. Seems to be that there is more camera bodies than good motors available so it may be worth it to investigate what kind of solutions could be made for these cameras and if there is a possibility to make the system more standardized and user friendly. The system is in very early prototyping stage ( I started the project in January this year and expect to have the fist working motor done by June) so it will take some time before it is refined enough to be used by other people.

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I tested the re-designed prototype circuit today with the actual Kinor camera. At this stage it is important to do the tests with actual cameras as well and preferably the cameras need to have a dummy film roll inside so that it resembles the real life torque requirements. By today's tests the oscillation becomes slightly stronger when you add more load to the motor which was expected... it is easy to fine tune the motor when it turns freely but when you add the actual film transport to the equation it changes dramatically. That was exactly what I wanted to test.

with the real camera and film at 720rpm target the rpm stability was pretty usable at about +10 / -15 range from the target. from the sound of the system it was clear though that I would need a little bit more accurate speed measurement with slightly higher sample rate. This is only specific to the Kinor motor, remember that I use the pilot tone generator of the motor for my speed measurements and it only gives one pulse per revolution from the single generator winding. With the "normal crystal sync setup" where one uses slotted encoder disc for speed measurements the system is much more stable because one gets dozens of measurements per revolution instead of the one in my current test setup. 

I think I will try to add more accuracy to the speed readings on the Kinor motor by adding another input from the second winding of the pilot tone generator so that I'll get two different speed readings on Arduino which can be compared in the code. I will also test a different approach to the motor speed control when "too high" / "too low" reading is detected by the system.

At least with the Kinor motor the motor load generated too much oscillation for my tastes when running at low speeds (this is because the PWM level for "motor power low" needs to be substantially low value so that the speed does not rise too high. But the torque requirements are pretty high even at low speeds so the PWM level for "motor power high" needs to be substantially high to be able to drive the film forward. this generates kind of oscillation where the controller detects lower than target RPM so it gives the "motor power high" command, then the speed rises considerably over the target RPM. the system detects that and gives instantly the "motor power low" command which drops the speed considerably lower than the target RPM and the cycle repeats over and over again.

This is what I was talking about earlier when mentioning "fine tuning the PWM values for each RPM" . The current version of the code specifies 6 preset RPM speeds (associated with the corresponding frame rates but the code handles RPM, not fps ) .For each RPM preset I can specify the motor speed "high" and "low" values separately. But the desired settings change based on the specific motor input voltage + torque requirements (they change the response speed/momentum) which is why there cannot be a single setting for all the 6 preset speeds but each one needs to be individually tuned to get the oscillation to the minimal level around the target speed. For example in the free spinning motor tests the fine tuning reduced oscillation in one test from + 30 / - 40 rpm to about +4 / - 3 rpm. The problem is that this is gonna change if there is considerable change in the camera load. With higher sampling rate (using the encoder disc) the tuning is easier because the mechanical parts have less time to react to the individual changes in the motor driving power. The prototype is running at adjustment rates of about 10 to 50 speed adjustments per second whereas with higher rpm sampling rate I could get from 200 to 500 adjustments per second which would probably be stable enough to resemble true crystal sync in best cases.

I will test some options of "auto-tuning" the stability in the program code. It will take some time and we'll see how it goes. The feature will improve all speed stability whether the system is "fine-tuned" or not but it is not that simple to write as one could think of. 

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Long story short, this "motor attitude control" is the reason why this type of system cannot be completely "plug and play". It should be much easier tuned when the sampling rate is higher due to a slotted encoder disc giving much faster and more accurate speed measurement data but the system still needs some fine tuning to work, especially the low speeds. Every person could easily do this by watching a 10min tutorial and reading some documentation (even if the changes need to be made in the code directly) but it might be a small barrier to the people who just want to shoot great stuff and not think about technology too much.

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One thing I was aiming with the user installable product was that this type of system would be much much easier and faster to repair if there would be something wrong with it. This was also why I started this project in the first place, it would have been easy to just send my Kinor motor to Olex for crystal sync modification or diy adapt my existing Konvas 2m crystal motor to work with it. But I would be totally screwed if the motor would develop problems with it in the middle of the shoot (either send your motor back to Ukraine for repairing or in case of the Konvas motor, try to hunt down a working specimen from eBay which is not overly expensive and works correctly. That can easily take months or more).

Instead I wanted a system more similar to an Arduino "shield" where you just have a circuit board with connector for popping in the Arduino and I could just have a spare board and spare Arduino with me as a backup on set so I could replace every part of the system easily and continue shooting in couple of minutes. Or if all my Arduinos would magically be burned or something, I could just go to the nearby electrics store and buy a new one, then use a laptop to upload the program code to it ON SET and continue shooting. I could even show the 2nd AC how to do that, the Arduino IDE (the software used to write, test and upload the code to the controller) is so simple to use that it would take 2 minutes to show them what to do. Or couple of extra minutes and they could tune the values directly in the code when shown what to look for. Watching a tutorial video and reading some documentation would enable them to install the whole system to the camera and troubleshoot it and tune it to their tastes.

The reason there is no this type of products commercially available yet is because there is not much demand for this type of custom speed stabilizing systems in other than the very narrow and rare camera motors market so no one has any interest in developing new products in this field. Other industries use different type of solutions for speed control so a system like this is very cinematography specific which is why I don't see a lot of commercial potential in it either (I have a small company here but don't see much commercial value in the project at this point, other than modifying my own cameras to work better on paid projects).

One of the ideas I had was that this could make a pretty OK kickstarter project which would pay the developing costs and the beta testers would get working prototypes which would be used to collect user data and help the further modifications of popular cameras like the NPR and the ACL. then the project would probably go open source at some point so that I could concentrate on other projects ( I have lots of them going on all the time, for example couple of film scanner projects etc. )  🙂  

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Finding a partner in US who would do modifications would be nice but I don't see real benefit in it commercially compared to another type of expensive sync motor modifications. I own a small company here in Finland which I could use for doing the modification work locally if needed but as said I see this as a user installable / user repairable product which would be customizable to individual needs, even in the middle of the shoot  🙂

 

 

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The Leicina 8 S, V, and SV have a DC motor with a centrifugal switch speed control like the Arriflex 16 self-regulating motors. About 32,000 Leicina have been sold. If you’d offer a small crystal control unit for a modern DC replace motor (26 mm outer diameter), you might generate some business. The camera has a straight-pull claw, lateral film guidance according to standards, and good lenses. In my eyes a compact camera for synch sound work. Thanks to the rectangular shape of the body a blimp housing can be fit quite easily. 960, 1000, 1080, 1440, and 1500 fpm would be perfect. Changing the battery to the 9 Volt block would make room.

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2 hours ago, Simon Wyss said:

The Leicina 8 S, V, and SV have a DC motor with a centrifugal switch speed control like the Arriflex 16 self-regulating motors. About 32,000 Leicina have been sold. If you’d offer a small crystal control unit for a modern DC replace motor (26 mm outer diameter), you might generate some business. The camera has a straight-pull claw, lateral film guidance according to standards, and good lenses. In my eyes a compact camera for synch sound work. Thanks to the rectangular shape of the body a blimp housing can be fit quite easily. 960, 1000, 1080, 1440, and 1500 fpm would be perfect. Changing the battery to the 9 Volt block would make room.

that sounds doable though because of the size restrictions a different type of Arduino need to be used. or another type of microcontroller which would make the programming a bit more time consuming.

it would also necessitate small circuit board and SMD components with full cad design and larger batch manufacturing. I believe something from couple hundred to a thousand board per batch or something like that. 

probably there would be some brushless motors which could fit the cameras. 

Sounds completely doable but the price of the modification may cause some restrictions. Probably the best approach would be to pre-sale the modified cameras and then do them in large batch to ensure efficiency. 

It seems the cameras are something around 100e price range at the moment. I believe the modification would raise the price to couple of hundred euros. Would that be too much for such a camera compared to the 8mm cameras which already have crystal speeds built in? 

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Shall we cooperate?

I see Leicina offered for $30 and less. A newly crystallized one could be sold for, I’m estimating, $600, with a three-years warranty. I could do the mechanical work and cleaning of the lens, you’d deliver the electronic unit. Motors that fit are readily available. The offer might include a delivery time of, say, two months. Three weeks with a sent-in camera. They are good cameras, having a low optical axis (not the lowest, though). I am speculating about the availability of Ektachrome in Double-Eight.

Kodak is not bringing the announced Super-8 camera, so 2 × 8 has a chance. We could perhaps add a ground glass to the finder, too. Its diameter is 12,99 mm.

Sound recording one way or the other, transfer to perforated magnetic film or tape, reproduction with an old-style sound coupler. Advantage is different speeds possible through the use of varying diameter drums. One such machine is the Bauer T 10. You can run it at 16 fps, the tape at 3¾ or 7½ ips. Paillard-Bolex M 8 runs from 12 to 25 fps at varying tape speeds. Big fun

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2 hours ago, Simon Wyss said:

Shall we cooperate?

I see Leicina offered for $30 and less. A newly crystallized one could be sold for, I’m estimating, $600, with a three-years warranty. I could do the mechanical work and cleaning of the lens, you’d deliver the electronic unit. Motors that fit are readily available. The offer might include a delivery time of, say, two months. Three weeks with a sent-in camera. They are good cameras, having a low optical axis (not the lowest, though). I am speculating about the availability of Ektachrome in Double-Eight.

Kodak is not bringing the announced Super-8 camera, so 2 × 8 has a chance. We could perhaps add a ground glass to the finder, too. Its diameter is 12,99 mm.

Sound recording one way or the other, transfer to perforated magnetic film or tape, reproduction with an old-style sound coupler. Advantage is different speeds possible through the use of varying diameter drums. One such machine is the Bauer T 10. You can run it at 16 fps, the tape at 3¾ or 7½ ips. Paillard-Bolex M 8 runs from 12 to 25 fps at varying tape speeds. Big fun

sounds interesting! after I have gotten the encoder disc prototype working correctly and tested with larger cameras it would be possible to start prototyping a Leicina or similar style project.

My current plan is to first finish the Kinor2m motor project, then to do the prototype encoder disc standalone motor for finessing the speed control stability on higher sampling rate system. Then I will probably adapt my 35mm Soyuz US3N camera for crystal sync because I use the same type of motor with it than the encoder disc test system will use so I can practically just throw the prototype in and fine tune and start shooting film. 

then it could be possible to maybe adapt some "easier" cameras like NPR and ACL if it does not need too much custom parts. The most challenging step is to try to fit all the needed parts in a small enough space so that they fit inside the existing motor housing without needing an additional box. If someone could live with the additional about palm or usb hard drive sized control box with 5 or 7 pin wire connecting it to the camera body, then it would make adapting very easy because I could even assemble the components by hand on pre drilled proto boards.

After that (probably this Autumn or so) it would be possible to start to miniaturize the setup and parts. It may be worth investigating to use hall sensors for rpm feedback on the Leicina motor if it seems more practical than the encoder disc. I would need a full camera with the intended motor replacement for tests but I believe it could be possible to start the project this year or at least the next Spring if it seems financially viable to do.

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I know you want to "create" a motor for your cameras and that crystal sync motor may not exist, but there are motors with old technology that work fine and that could be improved in some way. I mean I don't think there is anything wrong on reverse engineering a NPR or ACL motor that works just fine and just copy it or improve it. There are more cameras than motors and probably just using modern components would make them easier to get repaired for example increasing the reliability of cameras. You mentioned the struggle of trying to find another piece of equipment that it's going to fit your camera that it's going to be hard to find, you don't know if it's going to work and even if it works it's going to be old and you are going to be afraid of using it.

Even the newest film cameras, motors, controllers and accessories are free of patent restrictions now. In the USA a patent protect an invention for 14-20 years and after that it becomes "free" or "public" and they created that system so people can take advantage of their inventions for a period of time, but also to make it easier for people to see how it was done, improve it. Even hole cameras could be copied at this time including design. I'm not saying it's easy or a great business but we have computers, CNC machines and 3D printing technology today that manufacturers didn't have back in the 60's.

I'm sure is not easy, but maybe just copying some of those motors that already exist could create some cash flow that you could use later to develop motors that don't exist. At the end of the day film cameras being as complex and precise as they are, are simple machines compared to today's technology and some of them just need a motor and a CLA to bring them back to life.

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I considered reverse engineering too before starting this project. But by my opinion and based on the advancement so far I would say that in my situation it actually IS much simpler to design a system completely from scratch instead of reverse engineering and copying an existing design. Especially in the case of the US3N camera which is so rare that there is not even pictures of it on the internet except the ones I have uploaded there. Maybe one manual cover or something but thats it. It is a Soviet X35/Mitchell bncr hybrid and no motors available anywhere. Someone mentioned that bncr crystal motors might be adapted maybe but they are also rare. And I want the motor to be more lightweight and smaller because the camera body itself is not super heavy, maybe around 30lbs or so and it is self blimped so I would have serious use for it even when it is KS perf at the moment. An old video showing the camera body. I have a better temporary wild motor solution for it but would like to shoot sync sound with it  https://m.youtube.com/channel/UCRQ4FduL9HyTBzX34CDtY4Ahttps://m.youtube.com/channel/UCRQ4FduL9HyTBzX34CDtY4A

 

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I got some new ideas when walking the dog. When I got home I started to rewrite the code... and there will be fundamental changes to its structure and behavior. This is to address better the different torque requirements and inertia response of different types of motors on different types of cameras on different speed settings. 

This means the design specs will change as well. The main advantage is that it is easier to fine tune the camera by the end user if needed and the speed will be much more stable than with the old code versions.

The disadvantage is that if the code needs to be changed it may become incredibly tricky for the end user to do by themselves and that is why it may be too complicated for them to change the response curves directly in the code from now on. I could, however, make some kind of mechanical selector which switches between different response curves if someone would absolutely need that. it would cost a little more of course.

Most of the persons have asked for a custom system per camera model so an all-rounder design may not be beneficial goal anymore. I think I will rather change this being a custom product which is specially adapted by me for different camera models and then the system can either be installed by the end user or someone else can do the mechanical work of installing the boards and encoder discs and such. I can do it as well but it will cost more, especially because of the high shipping costs to here from the US.

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WHY I CHANGED IT!  that is because the preset speeds scale is so wide (my current prototype uses speeds from 12fps to 32fps but people have asked for top speeds of 50fps or more) which means there needs to be multiple different response + torque level combinations across the range. a simple adjustment does not correct all the speeds at the same time so with the old design the tuning could be done for mid speeds so that the high speeds were off and the lows were unstable, or for low speeds and then the mid speeds were unstable and the mids and highs were off. That is because the inertia of the moving parts and the friction (especially the one caused by the moving film itself)  change different amount on different framerates on different cameras. it is a logarithmic change and the previous linear adjustment approach could not address it fully.  The other reason is that I added a auto-stabilizing feature which reduces oscillation around the target speed to get closer and closer to it quickly. This feature needs the custom response curves as well.

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Design specs at the moment:

- there will still be the 6 pre-programmed preset speeds. The rotary switch is the easiest way to select these reliably without a display so I will keep it in the design.

- two fine tuning trimmers on the circuit board which the end user can access if needed. The basic response curves are made in the code but the fine tuning changes how these curves are implemented. 

- I will make different style of response curves when I get the encoder disc testing motor working. Maybe at least a dozen different curves for starters. And later on, curves on every adapted camera+motor combination. Then I can choose from them and fine tune when adapting the system to an actual camera.

- if I already have the data for a particular camera motor and body, then it is possibly to upload the appropriate custom software version to the board and ship the electronics for someone else to install it to the camera. I could probably do the installing here if needed but it may be more expensive because of the shipping costs. The code is customized per camera+motor combination.

- if the camera body / motor combination is new, then I will need to get the motor and the camera body here to do measurements and possibly rewrite parts of the code for this exact combination. also for getting measurements for the circuit boards which could fit to the camera, this changes from model to model. I may need to custom design the boards if there is not enough space for existing designs to fit. The benefit of this is that if you need a custom feature it may be possible to add it. For example if someone wants a DIP switch on the board which selects between different style of response curves it could be made.

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Price estimates!

Everyone is always interested in these so I am just trying to figure out how much it could cost per camera. Nothing includes shipping costs of course. The benefit of an user installable product would be that the shipping costs would be very small so it would be significantly cheaper. The goal is to make the installing relatively easy even if the end user does that. 

 

- new camera model and motor to be adapted. some customizing needs to be done and maybe limited designing of new parts. the price depends on the time it will need from me but I estimate it could be from 1K to 2K per camera model to do this. This would include adapting one camera body. In the very best case it might be two bodies. Depends on the amount of work needed. I would recommend a minimum of two cameras to be adapted if the model needs serious design work but singles could be done as well, it is just more expensive per camera.

- boards and installed software for known camera model and motor which is already adapted sometime earlier so that I have the data available to choose the right response curves and board sizes right away. Someone else will do the installing of the boards and encoder disc etc. and I will just supply the parts kit. Includes email support and some spare components if the board or sensors need to be repaired locally.  Price estimate could be about 300 - 400 bucks or so if the boards are done in small runs and could be lower if mass production is possible and there is high demand. Minimum order one board but there has to be enough demand so that I can sell at least couple of them per year. I would recommend pooling two or three cameras and then ordering the conversion kits at the same time. 

- known camera model and motor. I have all the data available, the board sizes and designs etc and just need to install the boards and software here. the camera is shipped to me and I will send the fine tuned setup back. Price estimate could be from about 500 to 700 bucks or so if custom mechanical parts don't need to be manufactured and the installing takes about one day maximum. Installing tends to need drilling of the housings etc and the fitting of the encoder takes some work and may require a custom spacer which I will need to machine by myself.

- mass production is a different matter. for example the system Simon described would be more standardized and cheaper to produce because the boards could be done in at least couple of hundred boards at a time and no hand assembling needed by me. 

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So there will be different style of models and always some customizing done. The one-design-rules-them-all approach was maybe not something people were interested in so I changed the approach 🙂

I might investigate later on if it's possible for me to do small runs of complete 16mm camera modifications and selling them as well. For example crystal sync modified Krasnogorsk 3 cameras for reasonable prices. Might be doable but we'll see. 

I will probably do some designs with other type of microcontrollers as well. Just need to get more familiar with them. Probably PIC or custom programmed AVR which don't run the Arduino code. We'll see.

I will probably release some old software versions to open source sometime later. The new code is so fundamentally different and better that I will abandon the old design and could as well write a simple version of it for everyone to use if someone wants to try by themselves. Release date TBA but probably next year or so.

 

Let me know what you think 🙂

I though it would be interesting for people to read these updates because they reveal the design and thought process used and how the goals and features change during the project timeline. I saw there was some earlier crystal sync threads on the forum as well but they did not end to a final product. I have a little different approach so I am pretty confident that some type of final products will be done already this year.

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Bolex International has a new owner, Mr. Ueter has sold to a Hugo Diaz last fall. Marc Ueter continues to work with the company. Another project could be to implement the crystal control in ESMs in order to do away with the external synch box. I should buy such an upgraded motor for Paillard-Bolex H cameras right away. Plug in a power cord, set speed, shoot. A solar cell power extension would be nice, too. Film has remained viable for documentary work, a film movie camera needs energy only during takes.

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1 hour ago, Simon Wyss said:

Another project could be to implement the crystal control in ESMs in order to do away with the external synch box. I should buy such an upgraded motor for Paillard-Bolex H cameras right away. Plug in a power cord, set speed, shoot. A solar cell power extension would be nice, too. Film has remained viable for documentary work, a film movie camera needs energy only during takes.

I am not familiar with those motors. only shot with the normal spring motor bolexes. 

Do you happen to have schematics of the ESM motor? is it one of those which were meant for pilot tone use and not having "real" sync stabilized sync speeds?

Solar cell extension should be easily doable. some kind of lithium ion battery should be added for power storage

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