I came across this little gem while I was patent-diving for a steam-engine valve. It’s an old-timey “portable burglar alarm” with a novel alarm system. It’s quite simple, but could be surprisingly effective at preventing illegal entry (or inducing sudden heart attack).
The alarm unit is hung from a peg above a door, through which the burglar would presumably enter. When the door is opened, it pushes the unit off the peg, and said unit plummets to the floor. When it hits the floor, the plunger “D” is pushed up into the housing, and firing pin “d” (lowercase) impinges on cartridge “c”, which fires, thus sounding an alarm.
It also makes provision in tube “e’ ” for storage of extra cartridges, a removable cartridge holder “B”, and a window through which the cartridge might be changed “a”.
The perfect way to prevent handlebar-moustachioed rapscallions from making illicit entry to your estates.
Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.
Join us every Wednesday night at 8pm ET for Ask an Engineer!
Learn resistor values with Mho’s Resistance or get the best electronics calculator for engineers “Circuit Playground” – Adafruit’s Apps!
Maker Business — Alibaba to invest $15b in tech, set up research labs around the world
Wearables — Hand beading mimicry
Electronics — Trigger happy oscilloscope?
Biohacking — Biohacking: Visioneer – AI Glasses to Assist the Visually Impaired
No comments yet.
Sorry, the comment form is closed at this time.