OS eBike: Open Source Electric Bicycle Design You Can Build
OS eBike: Open Source Electric Bicycle Design You Can Build
A guide for making a lightweight eBike design built with open source hardware and software you assemble and customize yourself.
A guide for making a lightweight eBike design built with open source hardware and software you assemble and customize yourself. Read more
The OS eBike is a design intended for those who are interested in learning more about electric bicycles or who want a fun electronics project which will result in a really useful finished product. As a backer you'll get guides and advice to help you work with a battery, integrate a bldc motor and motor controller, and program your own bicycle computer to get feedback while you ride. The bike is lightweight, powerful, and perfect for commuting.
BLDC motor controller
A VESC is at the heart of the bike and handles the BLDC (brushless direct current) motor control, receives input from the throttle or pedal sensors, and outputs data to the display to show speed, distance, battery statistics, or anything else you'd like to view while riding.
The VESC is an open source design which can be configured for a variety of applications. Software helps configure and tune your motor control and serves a a fun platform to get more involved in the heart of what makes and electric bike work.
Starter configuration files proven to work with the design's motor, are included to get you connected and rolling fast, but an almost endless amount of tinkering is available if you choose to tweak the controller settings, or if you want to go even further and start to learn about motor control via the source code.
Rear hub motor
China is king when it comes to motor manufacturing and the story is no different here. The OS eBike uses a very compact lightweight 250W, cassette compatible (freewheel version too), geared rear hub motor to assist your ride (freewheel option also available). Depending on wheel size, battery configuration, and controller settings, you can expect assistance up to about 20 mph, and plenty of torque to climb steep hills, even without pedaling.
The small size and lightweight were the primary factors in motor selection and help to maintain the bikes unobtrusive looks and ease of handling. However, if you choose to use a different motor (front drive, higher power, etc...) the rest of the system will accommodate you.
The display is based on an OLED screen and open source microcontroller platform and can be configured and expanded to show all sorts of information. Basics such as standard ride statistics like distance and speed are included, as well as controller and battery information like voltage and motor currents. With a little bit of modification, different viewing sequences, fonts, or even other inputs can be displayed or logged.
Base files are included with the standard outputs pre-programmed to get you up and running fast, but future modifications and additions are easy with the starter files and can help make your ride your own. Like most microcontrollers, extra inputs and outputs are available in the event you'd like to add things like GPS or a thermocouple to give you a temperature readout during your ride.
The battery pack is designed using common, quality, 18650 cells from Samsung. These are proven reliable and have a long life and good electrical characteristics for an electric bike application. The design's configuration provides about 20 miles of range, depending on use, and ensures a long life thanks to a balancing BMS (battery management system). It is easy to build and I have found it to be perfect for use on a daily commute as it provides plenty of assistance and range while keeping the bike light and stealthy.
Rider inputs include throttle or pedal sensors and an on/off switch for the battery. More inputs can be configured to switch controller operation modes or assistance levels for those wishing to expand on the basic capability.
Backer rewards - what you are supporting
As a backer, you should expect to receive a digital package which includes all of the information needed to source components, and then build out the OS eBike design to convert a new or existing bicycle into an electric bicycle.
- Documentation, instructional guides, and project website
The design and first build of the bike is complete and has been in daily use for about 6 months proving out its reliability. The source files are collected, example configurations complete, and the bill of materials and vendor information gathered. If funded, the projects plan will be to build a second copy of the OS eBike design and capture more photos and videos to document the steps and catch points you may encounter while building your own. CAD and step files for the few 3D printed brackets and enclosures will also be provided.
A website and forum will serve as a gateway to find needed parts and get support along the way if you run into issues during the build or operation of your project.
If the project is funded, the option to get a builder kit sent to your door will be avaliable. To ensure enough interest and community support in forums, a minimum number of backers is needed here. Initial backers at the builder level can will be able to upgrade to kits if desired after the initial funding goal is reached.
- Builder kits
If funded a kit will be avaliable for those who would like to source all the required parts at once. It will include a box of required components including the following, in addition to a few odds and ends not listed. Note, this is not a complete bicycle. This is a package of components to build and convert an existing bicycle into an electric bicycle.
Motor, VESC, Required connectors, Throttle, Battery Cells [12S2P], Brackets, Tabs, BMS, Shrink, Wire, Charge connector, On off switch, Bag / enclosure, 3D printed display enclosure, Microcontroller, OLED screen, Charger, Rim [26" or 700c]. Spokes, Nipples
- All backers
Anyone building an OS eBike design will need a few tools of their own to complete the project, most of which are already owned by most hobbyists and cyclists. A quality high power soldering iron, spot welder, a spoke wrench, common hand tools, and a laptop are all required and not included in any reward level.
This design relies heavily on some really great open source projects, without which, this wouldn't be here today. Thanks to those project creators and contributors.
Risks and challenges
I have built 2 electric bikes in the past. The first was from a plug and play style kit 3 years ago, and the second was the design described here which I completed in June of 2017, and ride 3-4 days a week. As an integration and test engineer I have a lot of experience with these types of systems and am familiar with the technical challenges.
During my career I've also experienced delays from sourcing parts even from reliable vendors on all sorts of projects. If a parts kit is offered, there is always supply chain risk to schedule.
Backer risks: This project is fun and, in my opinion, completely within reach of the average electronics hobbyist. If you can solder DIP or through hole components, accomplish a basic project with an Arduino and a breadboard, and fix a flat bike tire, I think you can successfully build an electric bike. But like any DIY project there are challenges. For example, truing a wheel can be tricky once you have the motor and rim laced together, but any local bike shop can help if you get stuck. Another challenge will be to ensure good connections in the battery in order to have reliable use. This design is intended to help open up the experience of building your own electric bicycle to those wanting to learn and build a useful end product.Learn about accountability on Kickstarter
- (21 days)