I could just get a tacky bell but hell no. I got this 120db portable alarm on a keychain gizmo from the source (Radio Shack).
This thing is really loud. And I know the pedestrians are going to hear this one when I come up on them.
The idea is to rip apart a Bullet type LED headlight. I already have the 5 LED Raleigh headlight which works very good for $9.99. I plan on getting another one and converting it into the horn.
I'll be ripping out the guts of the LED light, the guts from the portable alarm and swapping them. The idea is that where the 5 LEDs are at the front of light is where I'll place the piezo buzzer instead. At the back a wire will be sticking out that will go to a pushbutton switch which will be mounted on the left grip right next to the Shimano pushbutton shifter.
So my handlebar will look like it has two identical LED headlights but one of them will actually be a 120DB "horn". The left one is the horn, the right one is an actual headlight.
I'll post pics of the completed project as well as a "How-to" for anyone who's interested in building one for themselves.