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Introduction & why I am here in this forum
Gentlemen (Normand and Oran), today I joined your club (forum) because it looks like we might be 'the' only three visible persons in the internet/world trying to get an automatic seamless shifting solution for our bicycles done in combination with a Nuvinci hub (apart from Bosch and some other large companies that only want to build e-bikes meanwhile, but an e-bike is no option for me, I am still too young for such things, maybe later once I feel 'old' enough).
Since more than six years I was thinking about it once I heard about the Nuvinci hub. First I started to write an app for my Android phone, just to see if these motion sensors could bring me a benefit to go even further into a kind of predictive mode, when and how to shift. Once the app showed the first results I combined an Arduino with a Blue Tooth module and paired it to my phone, so speed data from the reed switch was processed within the Arduino and sent to my phone. Combining this with the motion sensor data from the phone would instruct the Arduino over Blue Tooth, what to do with a servo.
I came that far about three years ago, still without having bought a Nuvinci hub. Then I did not have enough time to go further and time passed.
But this changed this year, in summer I got a new N380, and bought a used N360 with the Harmony (servo Hi8) from ebay. My first intention was to control the Harmony servo via an Arduino via Blue Tooth by my phone. But then I had to learn that with mounting the Harmony servo to my very old, but also very reliable bike (Kuwahara), I would lose my chain tensioner due to less space left by the Harmony servo. I would have to cut the part of the frame away where the chain tensioner is mounted. And that's where I said stop. Once cut off, there would not be an easy way back to get the chain tensioner refitted and even if the transmission ration of the N380 is fully OK, I still like the idea having the chance to shift between the three still existing front sprockets to gain an even bigger transmisson ratio for rare extreme situations, but this will only work if I will keep the chain tensioner. So the Harmony servo was now pushed back, at least for a while. Originally I wanted to go for the h-Sync version of the Harmony servo anyway to utilise the CAN bus via an Arduino.
So now you may be able to understand where I want to go, and that's when I found you two guys doing it without the Harmony servo and I have to admit well done gentlemen!
Guess what I did the last days ... taking your idea using a RC car servo controlling the wires put into a kind of a box at a differnt place so that the chain tensioner can stay where it is, at least for the next development steps. Latest at this weekend I should be able to do the first test drives. Thanks to your pre-work!
- Michael
Wow! Quite an introduction my friend! Welcome to my workshop!

You and Oran will sure become firends fast as you are both alike from what I read!

I did not want to go all arduino / servo control on my Bike as I like to shift whenever I want... Although, my servo mount might be interesting for you!

Check this post out:

On my bike, I scrapped all the electronic in the servo and Wired the motor straight to a 3pos. switch on a single cell LiPo battery
Si ça a déjà été fait, je peux le faire
Si ça n'a jamais été fait, donnez-moi juste le temps de trouver comment !

Michael, great to have you as part of the club, glad you eventually found us. There doesn't appear to be any other people on the internet I can find doing the same thing.
It's always interesting to see how someone else approaches the challenge. Would like to know more about the mobile app with a predicative mode and the use of the phones motion sensors. My skills are more in the making and engineering, the code writing doesn't come naturally to me.

The homemade servo arrangement and keeping multiple chainrings is definitely the way to go. If the servo fails it's cheaper and easier to replace. Its also easy to program in the change of ratio so that cadence reminds constant during a front sprocket shift. With my two sprockets I can use a reed switch to detect derailleur position, three is more of a challenge.

Keep us updated on progress I think we can learn a lot from each others experience so far. We could be the first to take automatic electronic shifting to the next level.
- Oran

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