On Friday 10 January 2025 03:18:30 pm wn4isx via groups.io wrote:
BTW, I have a no name "made in West Germany" personal alarm that uses 6 AA cells, and has a battery powered siren. I found this pretty small metal box about the size about the size of a paperback with a pin, I pulled the pin and the resulting sound was so loud I couldn't think. No one in the thrift store could.
I managed to push the pin back in and the shop owner begged me to take it away.
I worked at a facility that frowned on firearms (as in we'll fire you on the spot). We backed up to an economically distressed area, I had to work really late several nights, I wore ear plugs on the way to my car, one night I was confronted by a group of yutes and pulled the pin.
To quote a song from my childhood....
Yeah, they ran through the briers and they ran through the brambles
And they ran through the bushes where a rabbit couldn't go
A NIST reference calibrated sound meter says the unit produces 130dB.
You might consider an audible deterrent.....
That reminds me of a device brought to me a while back, the circuit board contained 6 or 8 MOSFETs, and it hooked up to a horn-type tweeter. The guy that brought it to me told me that the battery had been hooked up backwards one time, and the unit refused to work after that. Looking at the board, I could easily see where one particular trace had opened up, acting as a fuse. My thought was to bridge that with a rectifier diode, and see if it still worked. It's somewhere in my "pile of stuff" and maybe if I run across it I'll give that a try... :-)
Six AA cells oughta work, I'd guess.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
