alt Hacker NewsCoincidentally, I bought a 12v car horn yesterday with the intent of wiring it into my ebike's power supply with a little button on my handlebars.
Not because of other cyclists or pedestrians wearing (anc) headphones but because modern cars are so heavily sound-proofed they don't hear a bicycle bell anymore. A recent incident with an inattentive taxi driver in a brand new EV nearly flattening me prompted me to want to pursue this.
I'm still waiting for my cheap AliExpress dc-to-dc step down converter but otherwise I have everything I need and I think it should work. The horn module itself is definitely loud enough: I connected it to a 12v power supply at my desk and jumped out of my chair.
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When I was commuting 60k/day on my bike in shitty suburban conditions, I used one of these instead - you get limited use per trip, but you can always fill it up with a CO2 cylinder/bike pump:
https://www.hpvelotechnik.com/en/recumbent-trikes-bikes/acce...
It is loud.
I did that, but I used battery - couldn't figure out how to hook up to the e-bike's 50v electrical system (plus the DC-DC converter with high enough current...)
So I am using LiPo 3S, 2200mAh. Works like a charm. I keep it at its storage voltage (3.7-3.8v per cell), and it hardly drained the battery (there is no paracitic drain). Whole thing was like $20.
for your safety, when people hear a car horn, they’re going to be looking for a car.
if you ever want an upgrade look into nautilus air horns. I had one on my 250cc Vespa that would clear an intersection.
Needs like 18 amps if that tells you anything.
> I bought a 12v car horn yesterday with the intent of wiring it into my ebike's power supply
Putting an aerosol fog horn (available from boating supply shops) in the bikes water bottle holder is much simpler, louder and more effective.
I had a digital bell from aliexpress on my winter commuter because pogies on the bars prevented a typical dinger. It was very annoying and very effective; my wife referred to it as "the friend maker".
on the rare occasions where I need to loudly indicate my presence to a motor vehicle I wouldn't really want to be moving my hands - if I have time to move a hand to a horn I probably have time to brake/manouvre instead.
Generally in those situations I shout really loudly at the driver, and in general they seem to hear me
If diy doesn’t work I’ve been using loud bicycle horn and it works great.
Squeeze horns are usually loud enough to be heard by cars in my experience.
I want to see a bike with a train horn. Cars do it all the time. [1][2][3][4] illegal and highly satisfying
People have used drills+pumps to drive similar hand-held horns at football games so it is doable.
[1] - https://www.youtube.com/watch?v=NOKgg5iCw_c
[2] - https://www.youtube.com/watch?v=enF0m6J7g2w [Tiny car with train horn]
[3] - https://www.youtube.com/watch?v=w31s5NsoOyg
[4] - https://www.youtube.com/watch?v=jLfD1AFsb1I