It's been a while since I last stumbled upon such a novel idea. With Robinhood and company getting into the betting markets, I'm afraid this idea will get a bad image and make it's adoption harder.
To me, NY Times' article lacks empathy. Andy Baio's farewell blog post is much more reflective of her personality and life, and so is her 2015 XOXO talk.
Keep an eye on those bolts, they're right next to the shaft where shear forces are huge and from the looks of it they are only M6. You may want to use a harder grade to reduce the chances of them being sheared off.
The decision to select this motor was mainly driven by what is available, price, dimensions and the size of the output shaft. The gearbox would not fit anything that has an output shaft smaller than 6mm. I knew that I'm not going to need all the power and also top speed.
The basic idea for the freewheeling chainring comes from tandem bikes, where one person should be able to pedal, while the second one doesn't do anything. I have never ridden a tandem bike, but this is where I got the idea.
There is also another detail, that you need to know, in order to understand how it all works.
Trial bikes (not trail bikes) usually have a special kind of drivetrain, where the freewheel is mounted on the crank and not the rear wheel. This allows for a very small rear wheel sprocket and extremely high gear ratios.
So to make this work, I used a trial bike crank [1] on which I'm mounting a special purpose freewheel [2]. The chainrings are mounted to the freewheel using this adapter [3].
Thank you! Yes, brakes are important and I have 203mm discs front and rear.
After building this, I'm dreaming of building something very elegant - a 50W to 100W torque generator that is tiny in size and very lightweight, and it fits within the hub of the wheel. Maybe not using batteries at all, but supercapacitors the are charged when you brake and discharged when you accelerate.
Yes, I have a long commute to work (18km one way) and this was my main motivation for building the bike.
On the controls side of thing, I have the ECU and an Arduino Nano. The Arduino uses the BEC port of the ECU as a voltage supply to run a simple routine translating the analog output (potentiometer) from the throttle handle to a PWM signal that the ECU can understand.
The way that the assistance work is that while you are pedaling, you can turn the throttle and adjust until you get the assistance you want - pretty simple. After a while it becomes natural.
