I would like to narrate a personal story from the late 80s. I grew up in a multi-family where my uncles own a lot of vehicles, including the left-handed drive Jeeps from the World War era (India uses Right-Hand Drive). Our siblings were raised by our grandmother. After she finishes cooking lunch, she always have the problem of gathering us around to eat. We would have all gone to the locality and the neighbors to play. She was always frustrated and furious about our lack of timing.
So, I repurposed a truck's horn so she can just press a switch and blow the horn loud enough for us to hear across the neighbors. I had it on the roof-top for quite a while, even after she passed away the next year. Thinking about it now, I know it was pretty reckless. It was so loud, that other families would remind their kids that -- that is the Food-Time-Horn.