One of the keys to efficient cycling performance is a consistent pedalling cadence. To achieve this the cyclist must always be in the correct gear, which can be tricky when your legs are burning and you’re sucking air. To aid in this task, [Jan Oelbrandt] created Shift4Me, an open-source Arduino powered electronic shifter.
The system consists of a hall effect sensor at the pedals to measure cadence, an Arduino controller, and a servo mechanism to replace the manual shifter. Everything is mounted in a small enclosure on the frame. The only way to get one is to build your own, so a forum is available for Shift4Me builders, where the BOM, instructions, code and other documentation is available for download. Most bikes should be easy to convert, and [Jan] invites builders to post their modifications and improvements.
Since the only input is the cadence sensor, we wonder if the system will interfere more than help when the rider has to break cadence. It does however include allowance to hold on the current gear, or reset to a starting gear by pushing a button. One major downside is that you will be stuck in a single gear if the battery dies since the manual shifter is completely removed.
As one of the oldest continuously used forms of mechanical transport, there is no shortage of bicycle-related hacks. Some of the more recent ones we’ve seen on Hackaday include e-bike with a washing machine motor, and a beautifully engineered steam-powered bicycle.
It seems that stick shift has become a sticking point, at least for American car buyers. Throughout 2019, less than 2% of all the cars sold in the US had a manual transmission. This sad picture includes everything from cute two-seater commuters to — surprisingly enough — multi-million dollar super cars built for ultimate performance.
But aside from enthusiasts like myself, it seems no one cares too much about this shift away from manual transmissions. According to this video report by CNBC (embedded below), the fact that demand is in free-fall suggests that Americans on the whole just don’t enjoy driving stick anymore. And it stands to reason that as more and more people live their lives without learning to drive them, there would be a decline in the number of teachers and proponents. It’s a supply and demand problem starring the chicken and the egg.
But giving up the stick is one more example of giving up control over the vehicle. It’s not something everyone cares about, but those that do care a lot. Let’s grind through the ebb and flow of the manual transmission — more lovingly called the stick shift.
Continue reading “Sticking Up For The Stick Shift”
We realize the transmission fluid of an automobile’s automatic transmission is used to transfer the power from the engine to the drive shaft. But after watching this Department of Defense video from 1954 we now have a full understanding of the principles involved in fluid coupling. Like us, you probably have seen a diagram of a transmission which shows the fan-like blades that are affected by the moving fluid. But it’s worth watching the 12-minute clip after the break to understand how that liquid is moving and why that matters so much in the design. The motion of the rotors, along with the design of the enclosure, causes the fluid to move in a continual corkscrew — the shape of slinky whose ends have been attached to each other. This type of illustration leads to an intuitive understanding of how it’s possible to facilitate an efficient power transfer using a liquid.
Check out some of the comments left in the Reddit thread regarding this film. We agree with [Runxctry]; there’s something about the format of the presentation that makes these informative and engaging to an almost addictive level. But maybe it’s just the engineering geek deep inside that’s cause these feelings?
Continue reading “Retrotechtacular: Fluid Coupling”