Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84 exptools; site ihlpg.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!ihnp4!ihlpg!fish From: fish@ihlpg.UUCP (Bob Fishell) Newsgroups: net.bicycle Subject: Building a LOUD horn Message-ID: <1119@ihlpg.UUCP> Date: Thu, 22-Aug-85 18:42:03 EDT Article-I.D.: ihlpg.1119 Posted: Thu Aug 22 18:42:03 1985 Date-Received: Sat, 24-Aug-85 18:23:52 EDT Distribution: net Organization: AT&T Bell Laboratories Lines: 86 *** AC T YOUR AGE *** Some time ago I posted an article on how to build a LOUD horn, mainly out of components available at your friendly local Radio Hack. With all the flack about obnoxious motorists lately, I thought I'd recap the article. A LOUD horn can help in traffic, believe me. It's saved my butt a couple of times. Parts List: 2 12-V buzzers. These are the round variety, made of steel, with one wire and a bracket on the back. The original recipe called for 6-V buzzers, but Hack don't carry 'em any more (thanks to the netter who pointed this out to me; sorry I clobbered your letter before I got a chance to reply). The 12-Volters work just fine. 2 9-V battery clips, like those used in cheap transistor radios. 2 9-V radio batteries, preferably alkaline. The carbon variety are a couple of grams lighter (for those who really care about that sort of thing), but won't last as long. 1 normally open, SPST, momentary switch. Electrical connections: __buzzer__ bike | | bike frame-----| |---( - battery +)---( - battery + )---switch---frame |__buzzer__| Mechanical assembly: Depends on what you've got lying around. I made mine out of chassis parts from old TV sets, but any of several materials should do. The buzzers have clamps in the back that will admit a rectangular brace about the size of a popsicle stick. I made one such brace out of an aluminum rail. I clamped the brackets down on either side and drilled a 5/32" hole on the middle. This mounts the buzzer on the front reflector tongue, but don't do it yet. I made a little basket out of strips of sheet metal. It's just the right size so that the two batteries sit snugly side by side in it. I taped the batteries together so they can be removed as a unit. Another 5/32" hole is drilled in the center of the basket's front. The basket goes behind the reflector tongue, and both the basket and buzzer assembly are mounted with the same screw. The parts I used are decidedly nonstandard, but I think you could use mending plates quite satisfactorily. Wiring: The buzzers only have one wire coming out; the body serves as the other connection. These are automatically grounded to the bike frame if you use all-metal parts, but you'll have to run a ground wire if you use plastic. Solder both the wires to the negative pole of one battery clip. Solder the positive pole to the negative pole of the other one. Solder the other's positive pole to a wire about 20" long leading to one side of the pushbutton switch (see drawing). Ground the other side of the switch to the bike frame. All connections should be secured with heat-shrink tubing. DON'T use electrical tape, because it gets gooey in a hot sun. My button is mounted on the handlebars just to the right of the stem. Tuning and operation: The buzzers I used can be changed in pitch by turning a screw in the back. I chose two frequencies that beat together rather unpleasantly. The noise they emit is thin and metallic, but very LOUD. It is so obnoxious that I don't use it on joggers or other bikes (unless they're wearing headphones) that I'm just trying to pass, but it gets attention QUICK in an emergency. The horn is LOUD enough to be heard clearly by a teenager in a closed, muffler-less Camaro with the radio blasting, and LOUD enough to hurt your ears if you blow it inside the house. I use it mainly on motorists, most of whom turn their heads in surprise at the decibels this mother produces. Serves 'em right, too. __ / \ \__/ Bob Fishell ihnp4!ihlpg!fish