I'm at work now... but it is easy..
you need a horn kit from an auto store (19.99-30.00)
you ned a GEL-CELL battery (any battery space (15.00-25.00)
depending on the AMP HRS.
then a few feet of tube, a fuse, a switch/button....
positive from the horn goes right to the fuse then to the battery. Use thick primary wire, red and black...
the ground runs from the horn to the button to the battery.
Now, you have a battery, connected to compressor with an air line running to the horn.
The only reason you're not running from the room, is because, luckily, you installed a button (between the compressor and ground....)
Press the button.... maybe disconnect the horn from the air line.... for testing, save your ears.... until you actually mount it on the bike.
I can take pictures of mine later... but I've posted tons before.
Search for Author: Wayne and keyword airhorn
you'll find a lot of info. For just a horn you'd be good to follow the setup Mbartell used... I have a huge pannier pack filled with stereo gear.... when all you'll need is a battery and compressor.... much smaller bag.
Mounting the ehorn is simple... deciding how and where you stash the compressor and battery is a different thing you need to customize that to your moped.
Mbartell actually moved his coil, to put the compressor in an invisible location.... that's cool.
The difference between our two mopeds, is that his has an airhorn, and you kinda have to look at it.. "Hmmm... how did he do that....?"
while mine, it's pretty clear that the air horn has something to do with the fat wiring harness and ariline running into the rear pannier pack.
BTW, Mbartell, what kind of time are you seeing before you need to recharge? I know it depends on how long you use it...
Have you considered bringing a big float to the beach, and then using your moped to inflate it??? Cool!! Save your energy for something better.
I need to write an airhorn FAQ, have Mbartell review it, and submit it to Simon for posting in articles....
Someday... so busy lately... but I DO have my moped shop and cellar workshop coming right along. that's progress... now I just need to order some parts I need.