I'v also found giving a little shout before a driver makes a right hand turn with out signaling is a great way to save your life, but i like my voice to not be raspy after running around town. This project started with a little 12 volt scooter horn that i ran off of 9 volts, and i found it just wasn't loud enough.
SO the car horn project was BORN!
enough from me, lets get on with it!
Step 1: Scavanging List
-Battery Pack (For this demo i'm using 12 volts of AA batteries, i strongly suggest for permanent use to get something rechargeable. You can safely go to 14 volts with these horns and some horns need at least 14 to function. Lead acid batteries are too heavy for most but would work great, I'm getting some discarded laptop batteries in a week.)
-Push Button Switch (get something you can imagine triggering safely and be able to reach your breaks. Be sure the voltage works for what you're doing.)
-Electrical Wire (I'm using 18 gauge to do the hook up, any will do.)
-Plugs and Hookups (to take the battery pack with you when you park, or to recharge it. Every horn is different to hook it up.)
-Hardware (anything to attach the horn to the bike.)
Things you should have:
-A Basic soldering set with solder, an iron and clean working space
-Multimeter, so you can test voltage with out blowing the horn every time
-Time, not a lot of it but a sufficient amount.