One of the difficulties of riding a bike is people. They get in the way and they simply don't hear shouts or bells. This is especially true on mixed use trails where they are wearing headphones and running in the middle of the path. What's the solution?

Ultrasonic bike bells.

This will penetrate past any noise cancelling headphone or even a loud car stereo, and put a warning directly into the brain of the person in your way. And since it can get more powerful the longer you press the button, you can reach out and warn people long before you would normally be able to shout, "Choose a side!"
-- unhelpful_fool, Jul 11 2019

Ultrasonic Interference https://en.wikipedi...und_from_ultrasound
2 slightly different ultrasonic outputs interfere; the difference is the audible signal. [neutrinos_shadow, Jul 12 2019]

audio beam focuses on one area https://www.mathwor...io-beamforming.html
[beanangel, Jul 12 2019]

"Dutch Reach" targeting graticule _22Dutch_20Reach_22...ting_20graticule_2e
Gets cyclists away from the dangers of motor vehicles, and into the hospitals and graveyards where they belong. [8th of 7, Jul 15 2019]

I'd buy one. I ride almost everyday, and it's dangerous when someone isn't aware of folks around them. You ever tried getting past on a sharp curve. Holy hell, you are lucky if you survive. I understand we must all make some sacrifices, but it shouldn't be at the risk of broken bones.
-- blissmiss, Jul 11 2019


It's fine as long as the broken bones belong to other people.
-- 8th of 7, Jul 11 2019


The underlying overarching problem is mixed-use trails. In the UK, there are growing numbers of combined bike-and- pedestrian footpaths, which is stupid. Also, because of this, people (and even cyclists) now assume that it's OK to ride on any footpath, which it isn't.
-- MaxwellBuchanan, Jul 11 2019


Worse, cyclists seem to think that it's OK to ride on the roads.
-- 8th of 7, Jul 11 2019


[MaxwellBuchanan], That depends on the location. In my area, it is legal for bikes to ride on roads and sidewalks. Which is good considering we are constantly battling for space against cars who think they are gods.

Which is another great use of this bell since it should be able to penetrate car windows and blast the drivers out of the way.
-- unhelpful_fool, Jul 11 2019


Well, in the UK it's illegal.
-- MaxwellBuchanan, Jul 11 2019


Can you cite a statute where ultrasonic bells are banned?
-- notexactly, Jul 11 2019


Ba-ding. I meant cycling on footpaths.
-- MaxwellBuchanan, Jul 11 2019


//put a warning directly into the brain of the person in your way// In fact, the person in your way will be completely unaware of your ultrasonic bike bell, because they will not be able to hear it. Hence the term "ultrasonic".

If it is just on the edge of normal hearing (say, 22kHz for a young person; or less for an older person), then making it sufficiently loud may make it just barely audible as a sort of undefined impression. But (a) they will probably not be able to locate the source and (b) any ambient noise will tend to camouflage it.
-- MaxwellBuchanan, Jul 11 2019


... plus (c) if they do hear it, they may simply assume that there's a flock of giant bats nearby.
-- 8th of 7, Jul 11 2019


What I am pretty certain [unhelpful fool] is talking about is ultrasonic interference speakers. See linky for a vague Wikipedian description.
-- neutrinos_shadow, Jul 12 2019


How can you be "pretty certain"? It didn't even cross my mind that that might be what this is about, and I've been thinking about that technology recently. That goes a bit beyond a bell, too.
-- notexactly, Jul 12 2019


I've been working on (okay, admittedly only a thought experiment at the moment) a limited-range EMP-type 'assistive device' (okay [8th], 'weapon') with which to pulse the illegal motorized vehicles passing through my property on the TransCanada Trail (which is zoned 'person-powered vehicles only, except wheelchair/mobility devices').

Now I want to attach it to my bicycle, triggered by the bell. [+]
-- Sgt Teacup, Jul 12 2019


[MB} I was wondering when someone would bring that up about ultrasonics. There is a workaround though. They have audio systems that can follow a person around a room so that only one person can hear music [link]. I think those could be repurposed. Aiming would be the complex thing. Perhaps just pointing with a gesture could be detected with a camera.
-- beanangel, Jul 12 2019


I worry about ultrasonics (even if audio-modulated). It's a bit like zapping the eye with far UV - you can't see it, but it's not a good thing.
-- MaxwellBuchanan, Jul 12 2019


^ We just haven't done the sciency thing and seen what patterns are helpful and what are damaging. Of course, it's a bit above the standard data sampling system unless the beaming product becomes a global fad. There is always computational models to help crunch the guesses.
-- wjt, Jul 13 2019


[notexactly], it was the only use of "ultrasound" that made sense in the context of a bike bell (not that "make sense" is a requirement around here...).
My brain works in mysterious ways.
-- neutrinos_shadow, Jul 14 2019


[Ian Tindale], Remember: slow traffic stay to the right.

That's the failure point at which all these problems happen. A clump of people with no way through is merely a group of self-absorbed people who have no concept that they are in a world with other people. This bell is meant to pierce through all their narcissism and remind them that they aren't wandering alone in a forest. Welcome to civilization, now make a path!
-- unhelpful_fool, Jul 15 2019


Just think of all the dogs you'll piss off with this.
-- RayfordSteele, Jul 15 2019


//What someone could invent is a way or means for cyclists to slow down or even come to a halt and dismount// Actually, opening a car door can achieve all that and more.
-- MaxwellBuchanan, Jul 15 2019


For which reason we commend to you the latest BorgCo road safety innovation <link>
-- 8th of 7, Jul 15 2019



random, halfbakery