Simple Normally Closed Switch

With all the high tech stuff on here I thought I'd do a reminder of keeping it simple. its uninsulated and I wouldn't trust it with more than a car headlight bulb 12V 5A.⁢it's most certainly not waterproof.

a wooden clothes peg. 2 drawring pins if you can get brass ones without the plastic coating so much the better. hook up wire of choice I've be used a twisted pair salvaged from somewhere for illustration.

if you've got plain brass pins skip this step. hold your pin in the peg to keep your fingers away from the blade and split the plastic off with your cutting tool of choice.

open your clothes peg insert pin between jaws close the peg (watch your fingers if the pin is longer than the thickness of the jaws) repeat on other jaw

if your pins were long enough to come through the jaws. clip the point off with side cutters and or file smooth.

disassemble your clothes peg. insert the pins in the jaws. reassemble the peg

it is easier if you wrap the bare end around the pin before you push it in place. other wise you have to prise the pin out a little then hook your wire under the pin head and push it home again. I've hook the twisted pair under one leg of the spring just to keep it tidy.

as a burglar alarm wedge open between door and frame when door is opened switch closes activating alarm. or as a trip line this requires an additional part.

to use as a trip line you need a small insulator. I've used a strip cut from a plastic card from junk mail. Any hard smooth plastic will do so would a wooden lollipop stick or coffee stirrer. file notches or drill holes so your line doesn't slip when tied on. knock a panel pin into your chosen support and install switch and trip line.