Steve Switaj Posted January 6 Posted January 6 It looks like the motor is geared to run faster than the movement. This is probably to minimize the motor size, a whole lot depends on the exact motor windings, but in a lot of applications a small motor running fast can generate as much usable power as a big motor running slow. Assuming you don't need the torque a small motor saves you volume and may reduce your current requirements. This is like Kamran's Arri S we've been discussing. That camera has a motor that runs at 3x the movement speed, adn there's 3:1 gear in the camera. Also, here's a copy of the user's manual with some schematics. https://canon-s8-repair.yolasite.com/resources/CP-16R/Cinema Products CP-16R User and Maintenance Manual.pdf Check out figures 19 thru 21 for an idea of all the tweaky circuitry that could go wrong in the days of analog PLL's. This is still a lot more digital and thus more reliable than the innards of some cameras go heavy on the analog where every capacitor is a potential source of drift. I can think of one manufacturer that has probably a dozen adjustment pots, all of which have contacts that get dirty and start to flake out. No wonder these things died young. Especially since moisture somehow always gets in to the case, then the camera sits there in a humid environment slowly corroding.
Vincent Wolfram Posted January 16 Posted January 16 On 1/4/2025 at 7:14 PM, Aapo Lettinen said: I often get very depressed by trying to help people with their diy projects, that greatly affects my own work. I am trying to make something different than most people and have too much invested to not worry about anything or to give away stuff which I need the money back from to get food. Probably wont visit this thread later. Read the cp16r manual, it helps a bit with the research. Good luck with the project! I feel you @Aapo Lettinen - and now i realized as to why you blocked me in instagram after shooting you a message regarding this topic... It has to be said though that with modern microcontrollers and motor control systems it is quite easy to build a reasonably precise - ie less than frame off error on a full mag, I built a prototype using a yet to be released ODrive micro controller, a standard BLDC motor and an 8129 impulse per rotation encoder on the motor axis. This way i achieve full closed loop control for any speed, as well as precise positional control of the motor and film movement. Features like the camera always stopping at an open viewfinder or very low speeds with intermittent motor movement are easily possible. The internal clock of the microcontroller offers 40ppm clock accuracy, throughout the -30°C to +85°C temperature band and the possibility of using external sync if more precision is required. 40ppm of error comes out to around half a frame on a 400ft 16mm mag. My prototype is built on a an Arriflex 16 BL with the 25fps gear set, some 3d printed parts and a common brushless motor. Target RPM is 3000 at 25 fps, 2 revolutions per frame, 2880 rpm at 24 fps etc. any speed between 0 and 50 is just a few commands away. My intent is to open source this project. with just a few hundred euros you can build your own for basically any camera - and i will gladly help anyone as its a passion project of mine. attached are some pictures i snapped over the last days, i will do a complete write up once my prototype is finished and running well.
Premium Member Aapo Lettinen Posted January 16 Premium Member Posted January 16 46 minutes ago, Vincent Wolfram said: now i realized as to why you blocked me in instagram after shooting you a message regarding this topic... It has to be said though that with modern microcontrollers and motor control systems it is quite easy to build a reasonably precise - ie less than frame off error on a full mag, I built a prototype using a yet to be released ODrive micro controller, a standard BLDC motor and an 8129 impulse per rotation encoder on the motor axis. This way i achieve full closed loop control for any speed, as well as precise positional control of the motor and film movement. Features like the camera always stopping at an open viewfinder or very low speeds with intermittent motor movement are easily possible. My intent is to open source this project. with just a few hundred euros you can build your own for basically any camera - and i will gladly help anyone as its a passion project of mine. attached are some pictures i snapped over the last days, i will do a complete write up once my prototype is finished and running well. I tend to have issues with open source people seeking confirmation for their own research instead of asking for how I would design things so if I catched that kind of feeling from the post I probably hit block without even thinking about it. Nothing personal, it is just a pattern I see regularly like noticing AI generated image on my feed and hitting hide without thinking Quote My intent is to open source this project. with just a few hundred euros you can build your own for basically any camera - and i will gladly help anyone as its a passion project of mine. This is the exact opposite of how I am working and thinking. By my opinion, motor systems need to be made from scratch for every camera model for them to be optimized and then that optimized design used for all the cameras of that model which are missing a motor. making multiple designs for same camera model is waste of resources unless the other model has some features which the previous model could not have. If wanting to save money it is possible to design "multi-purpose" motors which fit couple of different cameras but they will always be sub-par and have lots of compromises so the budget solutions only fit certain type of uses and others need full custom work. Additionally I think it is waste of resources to reinvent the wheel dozens of times if targeting the same camera model. For example every end user redesigning and remaking the mechanics and user interface causing lots of additional costs instead of making good-enough single design and then just copying it for the users which have the same camera. I get the feeling from that kind of stuff that people don't want to actually shoot with the camera and instead want to just make endless diy modifications to it using it as conversation piece or for youtube videos. Kind of the same than making table lamps out of Bolex cameras by removing the insides entirely and adding a led light inside which shines through the taking lens 😄 The reason why I don't want to contribute to threads like this is because it would not help much the open source projects discussed here (people seek confirmation for their own research instead of someone with entirely different design philosophy telling them to make stuff very differently and learning stuff they are not interested in) , would just cause tons of frustration for everybody which is also why I deleted some posts. Additionally I would feel letting down the "real customers" who want me to design stuff for them and who pay the costs with their hard earned money trusting entirely that I would find the best price-quality ratio solution for them and can build it so that they can just take it out of the box and start shooting. I don't want to let them down so will not want to waste resources by fighting windmills for not reason 🙂 I think it is wrong approach to try to design "multi-purpose fits everything open source super cheap diy camera motor system template" and instead even open source people should concentrate on specific camera models to make kind of custom made solutions which work well in that use. Like Kamran's motor is good for budget arri16s shooters and the 16s crystal motor I am designing is good for those who need more features ready-to-use solution and have a bit more budget than couple of hundreds usd. Eclair cameras are covered very well (Marek has the affordable Cameflex crystal motor, I have covered the ACL and NPR and the NPR still has good original crystal motors available too) so it would be waste of resources to open source Eclair stuff especially when they have complex pretty expensive mechanics needed and I already grabbed the rest of the customers needing ACL and NPR stuff. Cinema Products cameras have the kind of user base who dont want to tinker with electronics and mechanics much and dont want to pay for readily made solution either so CP16 and CP16R are a dead end for both open source and custom made motor solutions. People would not use even a open source system for them so not worth using time and money on designing. I mean the camera is not worth spending couple of hundred usd to make it working again (my 1-speed kits were pretty affordable) so I lost faith that people want to repair them at all 😮 The Arri16BL is pretty good platform for open source stuff as there is not that much readily available solutions for it and it needs some mechanical work which might be useful to diy because getting them custom designed would be too expensive for what the camera is worth for. So I would support open source Arri16BL motor system development as it makes lots of sense. But it should be a customised-to-16BL type of system with lots of time used to make it really well working with that camera instead of trying to make a "multi-purpose-kind-of-works-with-most-cameras-but-not-really-well-on-anything" system which people would only use because it is cheap, not because it is good for that use 🙂 keep the open source hygge nice and cozy, I will go back designing Aaton controllers now 😄
Premium Member Aapo Lettinen Posted January 16 Premium Member Posted January 16 Beaulieu cameras would also be good platforms for open source stuff as the cameras themselves are affordable but the design of the camera body makes electronics work very difficult so costs too much to make "commercial crystal sync solution" for them. If you can make built-in new motor controller for beaulieu 8 and 16 it would see some happy users I think 🙂 Open source video assist system with raspberry pi based image processing and hdmi + wifi output with android playback software would be much better as a open source project than any camera motor attempts I think. I could even contribute a little to that kind of project if someone would want to start it! basically using Pi camera as video tap or other camera connected to it, then streaming full frame to onboard hdmi display and to the app via wifi. Possibility to add framelines etc if needed and some kind of possibility to record to the app. Pi zero and normal pi models would be useful for this.
Tyler Fukuda Posted February 19 Author Posted February 19 On 1/16/2025 at 1:28 AM, Vincent Wolfram said: I feel you @Aapo Lettinen - and now i realized as to why you blocked me in instagram after shooting you a message regarding this topic... It has to be said though that with modern microcontrollers and motor control systems it is quite easy to build a reasonably precise - ie less than frame off error on a full mag, I built a prototype using a yet to be released ODrive micro controller, a standard BLDC motor and an 8129 impulse per rotation encoder on the motor axis. This way i achieve full closed loop control for any speed, as well as precise positional control of the motor and film movement. Features like the camera always stopping at an open viewfinder or very low speeds with intermittent motor movement are easily possible. The internal clock of the microcontroller offers 40ppm clock accuracy, throughout the -30°C to +85°C temperature band and the possibility of using external sync if more precision is required. 40ppm of error comes out to around half a frame on a 400ft 16mm mag. My prototype is built on a an Arriflex 16 BL with the 25fps gear set, some 3d printed parts and a common brushless motor. Target RPM is 3000 at 25 fps, 2 revolutions per frame, 2880 rpm at 24 fps etc. any speed between 0 and 50 is just a few commands away. My intent is to open source this project. with just a few hundred euros you can build your own for basically any camera - and i will gladly help anyone as its a passion project of mine. attached are some pictures i snapped over the last days, i will do a complete write up once my prototype is finished and running well. Vincent, This is actually INCREDIBLY helpful and I will follow up with you in the future regarding your entire pipeline for this build. I am in the process of building a motor for mine (with help from a friend of course) In hopes that more modern solutions can troubleshoot the lack of available motors left in the world. I love how small your motor nicely fits to the camera body. Keep up the good work and can't wait to see it complete! - Tyler
Vincent Wolfram Posted February 24 Posted February 24 On 1/16/2025 at 1:00 PM, Aapo Lettinen said: Beaulieu cameras would also be good platforms for open source stuff as the cameras themselves are affordable but the design of the camera body makes electronics work very difficult so costs too much to make "commercial crystal sync solution" for them. If you can make built-in new motor controller for beaulieu 8 and 16 it would see some happy users I think 🙂 Open source video assist system with raspberry pi based image processing and hdmi + wifi output with android playback software would be much better as a open source project than any camera motor attempts I think. I could even contribute a little to that kind of project if someone would want to start it! basically using Pi camera as video tap or other camera connected to it, then streaming full frame to onboard hdmi display and to the app via wifi. Possibility to add framelines etc if needed and some kind of possibility to record to the app. Pi zero and normal pi models would be useful for this. Hah, ive actually also done some work on that. my friend wrote some code that would take an exposure, triggered by an impulse (or the viewing screen getting bright), output it via hmdi and then store it until the next frame would be triggered. this *should* work for most typical cinema framerates between close to 0 and 30ish. We havent had the time to fully build the prototype yet. Sensor we were gonna use was a global shutter board to minimize any rolling shutter artifacts
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