Intro
- Author:
Nabil Tewolde
Follow @nabilt
- Version: 0.1
- Instructable: http://www.instructables.com/id/DIY-Electronic-Derailleur/
DIY E-Shift is a easy to build electronic derailleur built with open source tools. It has been tested with the RD-4500 Shimano Tiagra derailleur, but the general method should work with most Shimano parts. This project contains Arduino sketch, electronic schematics with Fritzing diagram, bill of materials and CAD drawings for the servo mount.
Motivation
- Once both derailleurs are electronic you get automatic trimming, which means no more chain rub!
- Easier/smoother shifts. OK so it's not super hard to change gears with mechanical levers, but going electronic means you get an accurate shift every time.
- Cheaper than the commercial alternatives. Like thousands of dollars cheaper...
- When your gear changes are combined with other metrics like your heart rate, gps, speed and incline you can improve your ride by finding your weakness. Were you on the correct gear on that incline?
- It's a conversation starter
- Adding electronics to anything is always cool!
Screenshots
Planned Improvements
- EEPROM wear levelling
- Waterproofing
- Machined servo bracket
- More advanced bike computer
Assembly List
| Label | Part Type | Properties |
|---|---|---|
| C1 | Ceramic Capacitor | package 100 mil [THT, multilayer]; capacitance 0.1nF; voltage 16V |
| J1 | HiTEC HS-225MG Servo | 4.8V/6.0V - 54/67 oz./in |
| LED1 | Red LED - 3mm | package 3 mm [THT]; leg yes; color Red (633nm) |
| Part1 | Arduino Pro Mini 3.3V | voltage 3.3V; analog pins 4; digital pins 14 |
| Q1 | NPN-Transistor | package TO92 [THT]; type NPN; part # BC639 |
| R1 | 100 Ω Resistor | package THT; tolerance ±5%; bands 4; resistance 100Ω; pin spacing 400 mil |
| R2 | 1k Ω Resistor | package THT; tolerance ±5%; bands 4; resistance 1kΩ; pin spacing 400 mil |
| R3 | Rotary Potentiometer (Small) | size Rotary - 9mm; track Linear; type Rotary Shaft Potentiometer; maximum resistance 100kΩ |
| R4 | 10k Ω Resistor | package THT; tolerance ±5%; bands 4; resistance 10kΩ; pin spacing 400 mil |
| R5 | 10k Ω Resistor | package THT; tolerance ±5%; bands 4; resistance 10kΩ; pin spacing 400 mil |
| S1 | Pushbutton | package THT; switching circuit SPST; default state Normally Open; Part# Omron/B3F-4000 |
| S2 | Pushbutton | package THT; switching circuit SPST; default state Normally Open; Part# Omron/B3F-4000 |
| LiPower - Boost Converter | 3.7V input; 5V output | |
| Lipo Battery | 3.7V 6A | |
| Aluminium Sheet | 6'' x 3''; .016'' thickness | |
| Protoboard | 3.2" x 2.0"; https://www.adafruit.com/products/571 | |
| 3 Wire Ribbon Cable | Length of your bike | |
| 22 Gauge Solid Core Wire | ||
| 3 Pin Molex Connector | ||
| 2 Pin Molex Connector x2 | ||
| Small Screw | ...... | |
| M5x10 Phillips screw | ||
| 2.1'' x 3.5'' x 1.25'' Project Box | ||
| 4 inches Velcro Tape | ||
| A few zip ties (just in case) | ||
| Single pole changeover switch rated for 10V minimum |
Shopping List
| Amount | Part Type | Properties | Sources |
|---|---|---|---|
| 1 | HiTEC HS-225MG Servo | 4.8V/6.0V - 54/67 oz./in | HiTEC |
| 1 | Ceramic Capacitor | package 100 mil [THT, multilayer]; capacitance 0.1nF; voltage 16V | Local electronics shop |
| 1 | Red LED - 3mm | package 3 mm [THT]; leg yes; color Red (633nm) | Local electronics shop |
| 2 | Pushbutton | package THT; switching circuit SPST; default state Normally Open; Part# Omron/B3F-4000 | Mouser |
| 1 | 100 Ω Resistor | package THT; tolerance ±5%; bands 4; resistance 100Ω; pin spacing 400 mil | Local electronics shop |
| 2 | 10k Ω Resistor | package THT; tolerance ±5%; bands 4; resistance 10kΩ; pin spacing 400 mil | Local electronics shop |
| 1 | 1k Ω Resistor | package THT; tolerance ±5%; bands 4; resistance 1kΩ; pin spacing 400 mil | Local electronics shop |
| 1 | NPN-Transistor | package TO92 [THT]; type NPN; part # BC639 | Mouser |
| 1 | Rotary Potentiometer (Small) | size Rotary - 9mm; track Linear; type Rotary Shaft Potentiometer; maximum resistance 100kΩ | Local electronics shop |
| 1 | Arduino Pro Mini 3.3V | voltage 3.3V; analog pins 4; digital pins 14 | Sparkfun |
| 1 | LiPower - Boost Converter | 3.7V input; 5V output | Sparkfun |
| 1 | Lipo Battery | 3.7V 6A | Sparkfun |
| 1 | Aluminium Sheet | 6'' x 3''; .016'' thickness | Local hobby shop |
| 1 | Protoboard | 3.2" x 2.0"; https://www.adafruit.com/products/571 | Local electronics shop |
| 1 | 3 Wire Ribbon Cable | Length of your bike | Local electronics shop |
| 1 | 22 Gauge Solid Core Wire | Local electronics shop | |
| 1 | 3 Pin Molex Connector | Sparkfun | |
| 3 | 2 Pin Molex Connector x2 | Local electronics shop | |
| 1 | Small Screw | ...... | Local hardware shop |
| 2 | M5x10 Phillips screw | Local hardware shop | |
| 1 | 2.1'' x 3.5'' x 1.25'' Project Box | Local hobby shop | |
| 1 | 4 inches Velcro Tape | Local craft shop | |
| 3 | A few zip ties (just in case) | Local hardware shop | |
| 1 | Single pole changeover switch rated for 10V minimum | Local electronic shop |
License
DIY E-Shift by Nabil Tewolde is licensed under the MIT license.