http://www.davidsteele.com/electronic_whistle.html

I've been thinking of dropping one of these down one of my bullhorns and rigging a cheap switch for a bell...

Active surplus used to be the bee knees but now they have no inventory and charge 3x what they used too, the gentrification of Queen continues. I miss the days of building overpowered hydraulic siege machines on weekends for fun. We still have a trebuchet that can chuck bricks at a stupidly high velocity...