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  1. #1
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    DIY Electronic Shift

    Take a look to this video where its shown an Electronic Shift operateing.
    It's fresh from the oven and I'm still improving the code for the automatic mode.
    For any question, do not hesitate to ask.


  2. #2
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    Sick!! Im an EE major and I have an uno rev 3, do you mind posting your code to get some ideas or maybe I can help improve it.
    What type of batteries are you using to power the system?

  3. #3
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    you do know you can take the microcontroller (ATmega1284P )out of the arduino development board right?

  4. #4
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    Nice science project.

    I always think it's a little comical that Shimano originally developed Di2 for townie and commuter bikes, not elite level road bikes.

  5. #5
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    So are you saying that you have some sort of feedback to auto shift for you?

  6. #6
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    We the people ... DIY electronic shift (some details)

    Quote Originally Posted by toot334455 View Post
    So are you saying that you have some sort of feedback to auto shift for you?
    Hi,
    I'm happy to notice that I'm not alone!
    Originally I started the project with the main target of developing a sequential shift. But once it worked fine I saw that was not so difficult to implement an auto mode. The first step was to calculate a ratio for each speed, then taking into account the speed and acceleration while riding the code is able to decide wich is the best gear. I has also to include some conditional statments to improve the performance and avoid too fast responses. Changing gears via code also enables to decide the exact moment when the change is performed, I mean when the position of the pedalier is above or below not in the middle qhen the force is greater. And the difference is noticeable, it's not necessary to give up pushing hard for a while to perform a shift and it operates smoothly. I've also possible implemented a delay between main & driven gears in function depending of if you are increasing or decreasing the speed. And finally, the code also includes positional offsets while shifting and positional corrections for when the chain is crossed.
    I'm still trying to improve some minor issues but the overall feeling is extremely satisfactory.
    Since the code is a draft version, it's not readable for anybody except for who has wrotten so I prefer to clean it up before sharing.
    About he battery I simply use 5 rechargable Ni-Mh 1.2V 2200mAh cells, and it last for at least 2-3 hours. I'm not already in enough good shape to exhaust it.
    If you are thinking about developing one similar shifter, I think you should start for the mechanical parts because is quite tricky to find components and fit all them in the correct position.

    Regards,

    Arnau.

  7. #7
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    Quote Originally Posted by toot334455 View Post
    you do know you can take the microcontroller (ATmega1284P )out of the arduino development board right?
    I worked at ATMEL and made those FPGA's, I also tested code for them. Now I am at INTEL and loving it. Nice to see ATMEL products still working out there.

    Mark
    2012 XXL Carve Expert

  8. #8
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    Awesome, fairly more in depth than initial glance.
    So basically you have a desired position based on speed and torque and the bike shifts to that position like an automatic automobile.

    What are you using to sense what position the pedals are at and how much torque is being applied?

  9. #9
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    Arduino + step motor?

  10. #10
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    And this is the first data collected in a real trip
    DIY Electronic Shift-captura.jpg

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