I'm wanting to install an N380 on a road bike. The issue is the standard NuVinci shifter doesn't fit curved handlebars. I could find a different shifter and modify it or make a shifter but I liked the idea of experimenting with an electronic shifter. I'm wanting to learn about Arduino's and programming, so thought I would base it around one. This would also give interesting possibilities of automating the shifting.
To start with I want to get it working as a manual shifter using a potentiometer as the handlebar control. Then I will move on to the challenge of changing the potentiometer from a ratio selector to setting the desired cadence.
![[Image: WP_20160405_010_zpsczujbjmg.jpg]](http://i1301.photobucket.com/albums/ag114/Ed_N_R/WP_20160405_010_zpsczujbjmg.jpg)
Very quickly put together a circuit and uploaded a basic servo control program to the Arduino, works great. The pulsed DC to voltage convertor circuits I'm hoping to use can be seen in the photo.
![[Image: WP_20160409_008_zpsgr9sq263.jpg]](http://i1301.photobucket.com/albums/ag114/Ed_N_R/Mobile%20Uploads/WP_20160409_008_zpsgr9sq263.jpg)
Next was making the mechanics so that the 180° of rotation of the servo is converted into 95mm of pull needed for the shift interface. The cable drum had to be made out of individual pieces as I have no way of turning it. This meant I could cut a cable anchor into the drum (see photo). This enables me to use second hand cable which has broken off in a shifter instead of buying two new cables.
![[Image: WP_20160410_015_zpsx0lhae48.jpg]](http://i1301.photobucket.com/albums/ag114/Ed_N_R/Mobile%20Uploads/WP_20160410_015_zpsx0lhae48.jpg)
This is how far I got with it today the servo can now control the shift interface. A couple of potentiometers just arrived in the post. One of them I'm interested in experimenting with is logarithmic. I'll set it up so that the shifter moves quickest in low ratios and slow near overdrive. This will better match the shift rate to acceleration and give better fine tuning when cruising at higher speeds. That's the theory but we'll see if its usable in practice. I expect there's a way of programming the Arduino to mimic this and in a more customizable way.
A few ideas I've got for automating the shifter. I will always want to keep the option of manual so will have a switch to select between manual and auto.
I'm currently planning to use reed switch sensors from a cycle computer and input into the Arduino as a voltage. For this I have two pulsed DC to voltage converter circuits that I made for a college project a while ago.
What I need to experiment with to find out which is best is whether to monitor wheel or crank rpm or both. I like the idea of monitoring cadence but I think it could result in a lot of unnecessary shifting. To reduce this might result in an annoying lag in shifting when accelerating. Wheel rpm would be more stable but I would need to program the Arduino so that it knows what servo position for any given speed.
Lots to think about but first I want to temporary attach it to a bike in it's current state to see how I feel about it. Then I can work on waterproofing everything.
To start with I want to get it working as a manual shifter using a potentiometer as the handlebar control. Then I will move on to the challenge of changing the potentiometer from a ratio selector to setting the desired cadence.
![[Image: WP_20160405_010_zpsczujbjmg.jpg]](http://i1301.photobucket.com/albums/ag114/Ed_N_R/WP_20160405_010_zpsczujbjmg.jpg)
Very quickly put together a circuit and uploaded a basic servo control program to the Arduino, works great. The pulsed DC to voltage convertor circuits I'm hoping to use can be seen in the photo.
![[Image: WP_20160409_008_zpsgr9sq263.jpg]](http://i1301.photobucket.com/albums/ag114/Ed_N_R/Mobile%20Uploads/WP_20160409_008_zpsgr9sq263.jpg)
Next was making the mechanics so that the 180° of rotation of the servo is converted into 95mm of pull needed for the shift interface. The cable drum had to be made out of individual pieces as I have no way of turning it. This meant I could cut a cable anchor into the drum (see photo). This enables me to use second hand cable which has broken off in a shifter instead of buying two new cables.
![[Image: WP_20160410_015_zpsx0lhae48.jpg]](http://i1301.photobucket.com/albums/ag114/Ed_N_R/Mobile%20Uploads/WP_20160410_015_zpsx0lhae48.jpg)
This is how far I got with it today the servo can now control the shift interface. A couple of potentiometers just arrived in the post. One of them I'm interested in experimenting with is logarithmic. I'll set it up so that the shifter moves quickest in low ratios and slow near overdrive. This will better match the shift rate to acceleration and give better fine tuning when cruising at higher speeds. That's the theory but we'll see if its usable in practice. I expect there's a way of programming the Arduino to mimic this and in a more customizable way.
A few ideas I've got for automating the shifter. I will always want to keep the option of manual so will have a switch to select between manual and auto.
I'm currently planning to use reed switch sensors from a cycle computer and input into the Arduino as a voltage. For this I have two pulsed DC to voltage converter circuits that I made for a college project a while ago.
What I need to experiment with to find out which is best is whether to monitor wheel or crank rpm or both. I like the idea of monitoring cadence but I think it could result in a lot of unnecessary shifting. To reduce this might result in an annoying lag in shifting when accelerating. Wheel rpm would be more stable but I would need to program the Arduino so that it knows what servo position for any given speed.
Lots to think about but first I want to temporary attach it to a bike in it's current state to see how I feel about it. Then I can work on waterproofing everything.
- Oran