CFWe are still working on the project. The new PCBs are running quite well. So a first prototype might be coming in the next weeks.
We are now fixed with four steppers for each PCB. So each bigger clock should have a horizontal number of individual clocks, which can be divided by four. For the smallest version of 24 clocks it fits perfectly and for any bigger one this shouldn't also be a problem.
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How did you find x40 reference point? The same small 1x2 mm magnets with hall effect sensor?
Can you show a picture of setup?
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I follow you now for some months and hope to see your 24 face prototype soon :-) What is the advantage to go with CAN compared to I2C communication? My project is build up with I2C as this was the easiest for me :-) As beginner in this topic, I didn't wanted to try other bus systems. But if there are better alternatives, I would be interested in. My approach is with an ESP32 as master and ATMEGA328 as slaves. Cost not a lot and works well. However, the I2C communication seems not to be 100% reliable, sometimes a handle get a wrong command??? So I would be interested to see the CAN alternative - if there are significant advantages.
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I2C is only made for short distances, like within the same PCB. If you think about a large array of individual clocks the distance between the master and slave PCBs can go up to more than 2 meters. With I2C it's propably only possible by using level shifters and set the signal to 12-15V. This may work, but I2C is still not made for these long lines.
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I agree. I almost went with rs-485 since it is almost unidirectional, but you basically need a physical layer that is long distance capable.
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I’m working on basically the same project. I’m also using can to address master boards with a micro driving 4 motors- just finished laying it out. I did elect to make each board seperate for each motor and run cable to each motor via ribbon cable for control.
Any reason you chose the stm32? I was going to roll my own Microcontroller board but I found it was cheaper to buy arduino nanos for $1...
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The STM32 as bluepill is also available for less than $2 and it has more memory space and CAN directly implemented. Also there are two SPI and two I2C. So more options for fancy additions...
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I ordered them at PCPWay, but any Chinese producer can do this. They are "only" 405mm wide. The steppers are a little bit noisy. For a clock with more than 100 faces it really could make some noise. So lets see, what the prototype with 24 faces will show to us.
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Yeah, they all do it. But at their own rates :) That's why I asked... But looking at your BOM, the PCBs sure aren't the most expensive part hehe
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Wow, those PCBs are huge! Where did you order them? DirtyPCB?
Anyways, smooth rotation of the steppers, are they noisy?
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