[Dave Schneider] has been chasing an electric-bike build for more than 10 years now. When he first started looking into it back in 2009, the cost was prohibitive. But think of how far we’ve come with the availability of motors, electronic speed controllers, and of course battery technology. When revisiting the project this year, he was able to convert a traditional bicycle to electric-drive for around $200.
Electric skateboards paved the way for this hack, as it was an outrunner motor that he chose to use as a friction drive for the rear wheel. The mounting brackets he fabricated clamp onto the chain stay tubes and press the body of the motor against the tire.
The speed of the motor is controlled by a rocker switch on the handlebars, but it’s the sensors in the brake levers that are the neat part. Magnets added to each brake lever are monitored by hall-effect sensors so that the throttle cuts whenever it senses the rider squeezing the front brake (effectively free-wheeling the bike), while the rear brake triggers a regenerative braking function he’s built into the system!
Sure you can buy these bikes, you can even buy conversion kits, but it’s pretty hard to beat the $88 [Dave] spent on the motor when the cost of purpose-built motors is usually several times this figure. The rest is fairly straight-forward, and besides ordering batteries and an electronic speed controller, you likely have the bits you need just waiting for you in your parts bin.
Electric bikes, and really all electric vehicles, have one major downside: the weight and cost of batteries. Even with lithium, battery packs for ebikes can easily weigh more than the bike itself and cost almost as much. But having to deal with this shortcoming could be a thing of the past thanks to [LightningOnDemand]’s recent creation. Of course, this would rely on a vast infrastructure of Tesla coils since that’s how this bike receives the power it needs to run its electric motor.
The Tesla coil used for the demonstration is no slouch, either. It’s part of the Nevada Lightning Laboratory and can pack a serious punch (PDF warning). To receive the electrical energy from the coil, the bike (actually a tricycle) uses a metal “umbrella” of sorts which then sends the energy to the electric motor. The bike drags a chain behind itself in order to have a ground point for the electricity to complete its circuit. There is limited range, though, and the Tesla coil will start ionizing paths to the ground if the bike travels too far away.
While we can’t realistically expect Tesla’s idea of worldwide, free, wireless electricity to power our bicycles anytime soon, it is interesting to see his work proven out, even if its on a small scale like this. Of course, it doesn’t take a research laboratory to start working with Tesla coils. This one is built out of common household parts and still gets the voltages required to create the signature effects of a Tesla coil.
There’s no better way of improving a project than logging data to make informed decisions on future improvements. When it came to [Brian]’s latest project, an electric bike, he wanted to get as much data as he could from the time he turned it on until the time he was finished riding. He turned to a custom pyBoard-based device (and wrote it up on Hackaday.io), but made it stackable in order to get as much information from his bike as possible.
This isn’t so much an ebike project as it is about a microcontroller platform that can be used as a general purpose device. All of the bike’s controls flow through this device as a logic layer, so everything that can possibly be logged is logged, including the status of the motor and battery at any given moment. This could be used for virtually any project, and the modular nature means that you could scale it up or down based on your specific needs. The device is based on an ARM microcontroller so it has plenty of power, too.
[Tom Stanton] is well-regarded in the maker community, and has put much effort in over the years on a variety of electric vehicle builds. In the process of upgrading his e-bike last year, he ran into some issues with the main drive pulley. Rather than rely on guesswork, he threw engineering at the problem.
The problem concerned the mounting bolts on the pulley’s hub, which would pull out under high torque. [Tom’s] initial finite element simulations had suggested the design was sound, but reality was proving otherwise. After further analysis and testing, [Tom] determined that his analysis hadn’t properly simulated the bolt pull-out condition. With this corrected in the software, it was readily apparent that there simply wasn’t enough material around the bolt holes to hold the torque load.
With the simulation now more closely agreeing with reality, [Tom] was able to correct the design. New parts were created with a strengthened mounting section, and the pulley was successfully able to deal with the loads in service.
It’s a great example of using engineering simulation tools to solve a problem quickly, rather than simply guessing and hoping things will hold up. We’ve seen [Tom]’s work before, too — like this fun backyard trebuchet build. Video after the break.
If you’re in a relatively urban area and your destination is within a reasonable distance, it’s hard to argue against riding your bike rather than taking a car. It’s a positive for the environment, and great way to exercise and keep active. But some of us, say folks who write for the Internet full-time, might appreciate a little electromechanical advantage when the going gets tough.
In an effort to make electrifying your bike as easy as possible, [Shushanik] and [Aram] are working on a product they call BikeOn which they’ve recently entered into the 2019 Hackaday Prize. Thanks to some very clever engineering, this small unit can clamp onto the frame of a standard bicycle and transfer the energy from its 350 watt motor directly into the rear wheel; all without any tools or permanent modifications.
In the video after the break, [Aram] demonstrates how the user can install the BikeOn motor assembly in literally just a few seconds. Naturally there’s a beefy battery that needs to get attached to the frame as well, but even that has been made modular enough that it can attach where many bikes have their water bottle holder.
The attentive reader will likely notice that there’s no obvious control mechanism for BikeOn. Instead of having to fumble around with it manually, BikeOn uses a combination of torque sensor, accelerometer, and gyroscope to intelligently determine when the rider could use a boost.
BikeOn nabbed Editor’s Choice award at Maker Faire 2019, and now that it’s in the running for the Hackaday Prize, we’re excited to see more information on the product as it moves towards commercial release.
Since then he’s designed and 3D printed an enclosure for his DIY battery pack and mounted it on his bike along with most of the rest of his E-bike kit. He couldn’t use the kit’s brake levers since his existing brake levers and gear-shift system share an enclosure. There also weren’t enough instructions in the kit for him to mount the pedal assistance system. But he had enough to do some road testing.
Based on a GPS tracker app on his phone, his top speed was 43 km/h (27 miles per hour). His DIY 5 Ah battery pack was half full after 5 km (3.1 miles) and he was able to ride 11.75 km (7.3 miles) on a single charge. So, success! The battery pack did the job and if he needs to go further then he can build a bigger pack with some idea of how it would improve his travel distance.
Sadly though, he had to remove it all from his bike since he lives in Germany and European rules state that for it to be considered an electric bike, it must be pedal assisted and the speed must the be progressively reduced as it reaches a cut-off speed of 25 km/h (15 miles per hour). In other words, his E-bike was more like a moped or small motorcycle. But it did offer him some good opportunities for hacking, and that’s often enough. Check out his final assembly and testing in the video below.
[EV4] is a small Polish company that makes electric vehicles, like this rather cool electric quad It’s an impressive build, including two 1 kW motors and a tilting turning system that makes it more maneuverable than most quad bikes. It has big, wide tires, a raised battery and longitudinal arms that mean it can climb over obstacles. That all makes it great for off-road use, and it’s just 60 cm (just under 24 inches) wide, which is much smaller than most quad bikes. It also has a top speed of 35 km/h, which would make it somewhat illegal to use on the public roads in many places. As someone who can’t ride a two-wheel bike because of a lousy sense of balance, I’d love to build something like this. Has anyone got plans for something similar?