Jump to content

Is there a demand for custom sync sound motors?


aapo lettinen
 Share

Recommended Posts



Excellent news. Did you use your AtTiny85 microcontroller system?

Did you also use the code that Friedermann wrote?

I'm still going down the route of Arduino running a controller I bought off eBay for a few quid. Haven't had the time to delve into it further as I've been working on the cameras which are almost done.

I have a couple of Cameflex motors that I need to put together. Once that's done then I'll look into controlling them with the Arduino set up.

I'm still looking into upgrading at least one of the motors to brushless and fitting the upgraded parts into an original Cameflex motor body. I think it's possible and will post photos when I've got it up and running.

Link to comment
Share on other sites

18 minutes ago, Marek Budzynski said:

Excellent news. Did you use your AtTiny85 microcontroller system?

Did you also use the code that Friedermann wrote?

I'm still going down the route of Arduino running a controller I bought off eBay for a few quid. Haven't had the time to delve into it further as I've been working on the cameras which are almost done.

I have a couple of Cameflex motors that I need to put together. Once that's done then I'll look into controlling them with the Arduino set up.

I'm still looking into upgrading at least one of the motors to brushless and fitting the upgraded parts into an original Cameflex motor body. I think it's possible and will post photos when I've got it up and running.

I used Attiny85 on these tests because they can be had in small 8-pin DIP packages which are easy to change between breadboards. There is disadvantages when integrating the whole control logic to one microcontroller (accuracy is one of the disadvantages if the running speed of the longer code is not fast enough) but it was needed on this stage of the developing to test the hundreds of small changes I made to the code.

 The code Friedemann posted previously was for dividing the crystal frequency in microcontroller to get accurate reference frequencies. It does not do anything else and that code cannot be used on Attiny85 without lots of modifications so I just wrote my own based on other examples found from the web. Making those reference frequencies is easy, the main challenge of these systems is in the actual phase locking fuction and motor control code. When I got my own reference frequency code working with the Attiny85 it was easy to add selectable frequencies to it without compromising anything. My current version has 11 selectable speeds from the same Attiny85.

If wanting to do the actual motor controller out of a microcontroller for these camera applications you need to write your own software and that is very time consuming. There is just bazillion different variables you need to take into account and test separately (how large of a phase error triggers how large of a correction without causing oscillation of the motor, etc.). The actual physical tests will take enormous amount of time, a lot of it is trial and error. That is why it took this much time for me to get promising results out of the system. 

----

 

I still think it was a good choice for you to choose the brushless motor route, they are just much easier to control with standard code. A real crystal sync motor can be more accurate but it is maybe 10x or 20x more work to get it working correctly and one needs more tools for it. Like I mentioned previously one needs to have at least the dual channel oscilloscope to be able to work with the real crystal sync prototypes. Otherwise you have no way to know it it's working correctly or not. You can't detect phase locking accuracy and phase errors with simple frequency meters or single channel measuring devices.

Link to comment
Share on other sites

  • 3 weeks later...

Just a quick update of my working process in case someone is interested. This is basically what I am doing hours and hours and hours at a time. 

https://www.youtube.com/watch?v=G0fGxUU3NB4

Writing new software or making small changes to the old one. Then uploading the altered program to the Attiny85 microcontroller, transferring the controller to the testing area on my kitchen table and installing it to the breadboard. Then running the motor with different speeds and friction settings and measuring how the speed lock behaves. Then going back to the computer with the results and repeating the process. 

I wrote a completely new phase locking code just couple of days ago based on all my previous designs. Works pretty OK now. There is also the 240Hz reference oscillator with dividers in the video. 

Edited by aapo lettinen
Link to comment
Share on other sites

  • 1 month later...
On 5/29/2020 at 12:23 AM, Marek Budzynski said:

Great video. You must be so pleased that's it's working. I haven't had a chance to work on mine yet. I'll post a video on Youtube when I sort it out.

Well done.

Cheers

Thanks! I got the Leicina S to work in crystal sync as well. Currently having another project as well which uses external control box to house the electronics. I am developing the display functions and user interface for it at the moment, so much fun! Making a new user interface is the most interesting part of modifying cameras by my opinion :) 

Anyway, I hope you get the brushless motor system working soon!

I have another project as well, I am finally intending to modify my Soyuz US3N camera to crystal sync at the end of the year. For it I purchased these motors because the camera does not have any original motors and this Chinese motor model seemed suitable.  https://www.ebay.com/itm/DC12-24V-30W-permanent-magnet-motor-double-shaft-ball-bearing-generator-motor/142341645472?hash=item21243924a0:g:9pkAAOSwbWpegW1e

So I am developing a Crystal Sync modification for those 12v 30w motors which is not camera dependent (as long as the gear ratio between the motor and the movement is known by me and the motor power is enough to run the camera at stable speed). If, at some point, it seems that you still want to change the goal back to brushed motors and traditional Crystal Sync, it is possible for me to build you one of those 30w motor systems with the external control box with display and multiple speeds which uses that Chinese 30w motor where I have already installed the encoder. OR just a basic cheaper control system with one single speed and no display if you want :)

Then it should work with different cameras by just making a mechanical axle adapter and support system for it by yourself. Needs some fine tuning of course but this is definitely an option if you are interested :)

Link to comment
Share on other sites

Aapo,

           I'm interested in everything that you're talking about. How I've progressed is that I have a couple of BLDC Hall censored motors that I got from eBay for £10. I got some motor controllers from Amazon for £4. Wired them up and got them to work. I also got a Arduino mini that can control the motors. Got all of that to work using Youtube videos as a starting point. I then found a bit of existing code that measures the speed of the motor accurately. So, all I've got to do now is figure out how to use the motor speed information and loop it back into controlling the motor for my desired speed. 

I've also managed to find a place called Backspace which has a lathe and milling machine so I'm going to try my hand at replicating the  Cameflex motor with a couple of modifications. Unfortunately the space is close until virus time stops. 

I also managed to get a couple of Cameflex 6v Type 24 motors to run but am still trying to work out why they only work intermittently.

I'll upload some photos in due course. 

p.s. I saw one of your 35mm black and white tests on Youtube. Looked really lovely. Nice one.

Cheers

Marek 

  • Upvote 1
Link to comment
Share on other sites

39 minutes ago, Marek Budzynski said:

Aapo,

           I'm interested in everything that you're talking about. How I've progressed is that I have a couple of BLDC Hall censored motors that I got from eBay for £10. I got some motor controllers from Amazon for £4. Wired them up and got them to work. I also got a Arduino mini that can control the motors. Got all of that to work using Youtube videos as a starting point. I then found a bit of existing code that measures the speed of the motor accurately. So, all I've got to do now is figure out how to use the motor speed information and loop it back into controlling the motor for my desired speed. 

I've also managed to find a place called Backspace which has a lathe and milling machine so I'm going to try my hand at replicating the  Cameflex motor with a couple of modifications. Unfortunately the space is close until virus time stops. 

I also managed to get a couple of Cameflex 6v Type 24 motors to run but am still trying to work out why they only work intermittently.

I'll upload some photos in due course. 

p.s. I saw one of your 35mm black and white tests on Youtube. Looked really lovely. Nice one.

Cheers

Marek 

Excellent! so it sounds like you are close to getting it work in stabilised speed. 

How does it get the speed measurement and how do you write the desired motor power in the code? 

With my old "speed-stabilised" system I used PulseIn function to read the frequency from the motor encoder (the PulseIn function on Arduino uses microseconds measurements of the pulse duration and this can be easily calculated to frequency measurement number) . Then this number is compared to the target speed number you want to reach (with 10-slot encoder that would be 250.00 Hz for 25fps). With if-functions or similar you can change how the system changes the motor power if the speed measurement number is lower or higher than the target. And how much it changes that if the difference is small or large. 

So you will create a loop where high speed measurement number compared to the target reduces motor power and low measurement raises motor power. It is up to you and needs to be defined by testing how much of a change it needs to be to get the best constant speed accuracy with the least amount of oscillation. With my old system I used an integer where I stored the current motor power number and if the speed measurement was higher than desired the code reduced the value of the integer and if it was lower it added to it. Then the value of this integer was written to the pwm output. You need to take care of the possible overflows and the uncontrolled large power value fluctuations (remember that the program loop is running at least hundreds of times per second so it may change the motor power between 0 and 100% back and forth without the mechanical system having enough time to respond. So it can adjust the power too quickly. So you probably need to figure out how to slow down the speed changes a little so that the program does not over compensate but responds at a pace the actual motor and camera movement is able to follow. 

So you will probably want a integer which stores the motor power value. And a speed measurement number which you can compare to the target speed you want. This way you can calculate the speed difference and change the motor power integer value up or down as needed. Finally you will write this value to the motor controller. Keep in mind that the loop easily over compensates so try to start with small changes first and test how it behaves. You need some kind of accurate speed measurement device to see how the system behaves. 

Adding more inertia to the system tends to make it run at too high speed if you keep the adjustment values the same. so you may need to lower them even more then. You just need to test a lot to figure out the correct numbers. But as said, start with low corrections first to avoid throwing the motor power constantly from 0 to 100% which creates lots of inaccuracy and oscillations. small is better in this case 🙂

Link to comment
Share on other sites

  • 2 weeks later...

One of the biggest problems so far is that I have so many design ideas and have done research for multiple different camera systems to be able to modify them, but the potential end users stay completely silent so I have no idea which of the projects are worth giving more resources for and which should be abandoned because of low interest.

I have one Konvas motor project I am working on which is ordered by a customer (that one I will surely finish because I know the system is needed) and then there is the Leicina S crystal sync project which I am working on as well but getting no feedback at all and thus I have no idea if anyone would order the final system or even has any interest in it in the first place. There was one experimental camera project as well which seemed very promising but the designer bailed out for some reason and I have not been able to contact him since. The Crystal sync design for that camera was almost finished so it is sad that the project did not work out.

Actually it is getting pretty depressing. For example the Eclair motor projects: I can see that people are reading the threads but there is no responses at all and no one is reacting in any way. No thumbs ups even. It gives an impression that no one could care less. The way I understand it is that people don't want this kind of motors to be done because no one needs them. That means that I can't invest any financial resources or much more time to those projects and they move down in the priority category until in the end they may be completely abandoned. 

I don't want to make these systems only for my own fun. I would like them to be used by others and them to help bringing old movie cameras back to life so that new users could find them and use them for their art. Couple of the proposed systems are totally new and would change the way those cameras could be used. To me it looks like that no one else is seeing any of those possibilities (for example the ability to make sync sound movies in Double 8 film, or making the rheostat Konvas model run in crystal sync which is completely new possibility and there is nothing similar done before)

But I totally get it why there is only something like 10 persons in the World who do usable Crystal Sync modifications for film cameras. It is because most people couldn't care less about these modifications and there is rarely anyone actually ordering them. No one cares to design Crystal control systems for rare camera models because there may be only one person in the World interested in it. Or in the worst case, none. Maybe it is partially because people are very conservative about camera and lens choices and hesitate trying any new possibilities? They are forever stuck with Arri cameras and never going to test anything new. There is no "what if this or that could be done" attitude, there is only "this is how everyone else has done it for decades so we're going to do it exactly the same way".  

The way I see it, there is an endless number of opportunities wasted because of the attitudes out there. People sticking with the old solutions, bashing down or ignoring any new development in the field. This halts any progress in film based image origination and gives even more way to the continuously evolving digital technology. The end users are partially responsible of the dying of the film. Partially because there is a complete overwhelming silence when someone tries to make any new film based solutions to get even a little bit of progress in that field. 

I always have the possibility to use my energy and resources to something else. For example designing new experimental scuba gear would be pretty neat. Distance meters and so on. I also have the possibility to shoot digital too so no need to stick with film unless I want to 🙂

Link to comment
Share on other sites

we use a brushless motor with hall sensors to control the motor phases, and an optical encoder for feedback. We have the same encoder that uses arri sr3, 416...

Edited by Max Ivanov
Link to comment
Share on other sites

2 hours ago, Max Ivanov said:

we use a brushless motor with hall sensors to control the motor phases, and an optical encoder for feedback. We have the same encoder that uses arri sr3, 416...

great that there is still others working on these systems as well! do you have specific camera models in mind which your system is meant for or is it a universal system which is easy to adapt to various camera models? I would love to see someone modifying Krasnogorsk cameras to crystal sync, I checked the possibilities with K2 a while ago but I don't have any suitable brushed motor which fits inside the camera body. Brushless motors could still work with these cameras for having higher power to size ratio. 

My own designs are all based on brushed motors. more "traditional" so to speak. the idea is to use the original camera motor as often as possible to avoid extensive machining work and the brushed crystal system can be made very small depending on the frequencies and interface needed (with my current techniques it is possible to make the control system approximately the same size as a 2 euro coin depending on what specs are needed)

Link to comment
Share on other sites

I'm still interested but looking for the cheapest solution possible. Currently working with a $10 BLDC with Hall, a $4 motor controller and a small Arduino. I can run the motor and control it from the Arduino. I just need to spend a bit more time on that as I'm currently preparing a couple of Cameflex CM3's to sell on eBay in about a month. Once I've done that I'll be back on the motors. All this is predominantly to shoot my own stuff. I'm also going to mill up some aluminium bobbins for my 100' mags. If there's any interest I might make a few for sale. I recently got a 100' mag with an original plastic bobbin so it'll be a direct copy. Also sorting out milling up a shaft to adapt the 100' Cameflex mag to accept 100' Daylight Loading spools. Oh, and also milling a motor body out of aluminium in the style of the Type 24 motors that will be around the same size as the original but with the extra electronics inside.

Then when I'm finished with all that I'll be looking to convert my other CM3's to Techniscope. I think I've figured out a way but need to work on the gearing of the magazine for the 2 perf pull down. It's a very simple idea and just requires some minor modifications and it should work a treat.

Awaiting delivery of bunch of Camematic and Cameflex motors I found on eBay. Mostly 24v but I'll see what I can do with those when they arrive. So, I may have some Type 24's for sale soon as well.

I'll keep you posted as to my progress.

 

Link to comment
Share on other sites

5 hours ago, Marek Budzynski said:

Awaiting delivery of bunch of Camematic and Cameflex motors I found on eBay. Mostly 24v but I'll see what I can do with those when they arrive. So, I may have some Type 24's for sale soon as well.

Oh it was you who purchased that motor lot I followed!  

I was afraid that some collector got them and they would never be seen again. Good to know where they are and they are put in use 🙂 

When you have spare motors at the end of the project, please put them back to sale so that it is possible for others to use them on their cameras. if you have spare Cameflex bodies it would be good to pair them with the motors of course and sell them together. there is lots of bare Cameflex bodies on eBay right now but very little motors available 🙂 

Link to comment
Share on other sites

Don't think they're the ones you were looking at. Two of them are 24V DC and one of those is a 16fps Rank Shunt Motor. There's one for sale on eBay at the moment in New Zealand.  The other is a 27V AC Kinotechnique one. No idea where to get at 27V ac power source. It may be that it's use for single frame operation.

The Camematic motors are fairly unique. One even has a speedometer built into it, same as the one on a CM3. Looking to see if they all work and if they can also be modified for Cameflex use. If not, they'll be back on eBay in a couple of days. I'll see if I can get ll the others working and thenI'll sell the Type 24's in due course.

  • Like 1
Link to comment
Share on other sites

9 hours ago, aapo lettinen said:

great that there is still others working on these systems as well! do you have specific camera models in mind which your system is meant for or is it a universal system which is easy to adapt to various camera models? I would love to see someone modifying Krasnogorsk cameras to crystal sync, I checked the possibilities with K2 a while ago but I don't have any suitable brushed motor which fits inside the camera body. Brushless motors could still work with these cameras for having higher power to size ratio. 

My own designs are all based on brushed motors. more "traditional" so to speak. the idea is to use the original camera motor as often as possible to avoid extensive machining work and the brushed crystal system can be made very small depending on the frequencies and interface needed (with my current techniques it is possible to make the control system approximately the same size as a 2 euro coin depending on what specs are needed)

Yes, brushless motors are more powerful than ordinary ones, but there are very few modifications with built-in hall sensors that are necessary for its precise control ... we did not consider brushed motors, they are outdated ... 

Edited by Max Ivanov
Link to comment
Share on other sites

On 7/8/2020 at 12:01 PM, aapo lettinen said:

With my old system I used an integer where I stored the current motor power number and if the speed measurement was higher than desired the code reduced the value of the integer and if it was lower it added to it. Then the value of this integer was written to the pwm output

Aapo, have you considered using a PID-Controller? That's pretty much what they were invented for. There is even a great PID library for the ATMegas. Tuning the PID can be a bit fiddly, but no need to re-invent the wheel here, and a PID would work with any motor and basically any kind of motor, too.

I love your Frankenstein-Breadboard-Setup though, looks exactly like the dozen of projects waiting on my desk for being finished 🙂

Link to comment
Share on other sites

11 hours ago, Friedemann Wachsmuth said:

I love your Frankenstein-Breadboard-Setup though, looks exactly like the dozen of projects waiting on my desk for being finished 🙂

I am constantly running out of breadboards and jumper wires which is why I need to spend some time making circuit boards every now and then to get the breadboards clean for another project 😅

Link to comment
Share on other sites

On 7/18/2020 at 10:48 PM, Marek Budzynski said:

PID. Thanks for that I'll be going down that route in parallel to the BLDC motor controller and Arduino as it's much smaller than the PID H bridge I've come across. However it's a really cheap price which is what I was after initially.

the systems I have made by myself are basically self made PID controllers with lots of additional components. that is because I could not find anything useful for my systems which would have been customizable enough and small enough and advanced enough so that it could be made to work with any camera system and would still be compact enough to fit inside any camera without effort and still would be very accurate as well. I found it easier to make my own controller by programming but on the other hand that took lots and lots of time. 

by my opinion, really cheap does not work on this application. Or it may work if you already have the tools and are ready to use maybe months to program bare microcontrollers like I do. And if you don't invest enormous amount of time, then you have to invest lots of money to purchase something readily available which may not fit the application perfectly. Everyone would be doing these if it would be easy and fast and cheap all the time and I would have used readily available products too if there would be any which would fit the job 🙂 

Link to comment
Share on other sites

Aapo, Sorry to bother you but I think you may be able to help me? I managed to get one the motors running that I go from eBay. I think I've identified it as a 12vdc Perfectone that runs at a constant speed. It has a synch pulse output which I think is similar to the some of the NPR motors. Not sure how fast it runs yet. However I got it running by accident when I by passed what I think is a capacitor. It's marked up as .22/300 B32 226. I think it's a Siemens. Could you suggest a replacement as I have no idea where to begin or how to identify what spec it is?

Cheers

Marek

 

B32226.thumb.jpg.972222255bd917ff9647c74c0d1d3194.jpg

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...