"Last Day" magnetic sonic cube landmine

Step 2 The switch

The only hard part of this was getting the trigger put together and dialed in. I had to mount the switch to the side of the box, then find a small metal bar to act as a lever. Then I attached a metal weight to the other end of the bar. When a magnet is below the box, it pulls the weight down, disconnecting the battery from the alarm. When the magnet is removed, or the box moved, the weight goes up, connecting the alarm to the battery. Check the notes on the pictures.

Comments

[RGM La Paz]

where can i buy a reed switch at and how much is it

[account3r2]

you can find them here $1.00-$1.25 USD

[neardood]

Okaaaaay. Y dont you just make life easier 4 yourselvs and put a magnetic reed N.O. (normally open) switch in the bottom of the case. You can gett any means of buzzers and alarms from radio shack or dick smith's.

[TheMadTinker]

He did say that he didn't have one of those lying around, so he improvised one.

[neardood]

no offense, but if you can't waltz into you're local electronics dealer and by a 4-cent magnetic reed switch, then you probably just dont have any common sense. However, the build is facinating and I cant understand y u would put yourself through so much strife to do something so simple?

[Akoi Meexx]

I have yet to see a four-cent reed switch in Radio Shack.

[DavidRobertson]

4 cents. Wow. Its so much cheaper in America.

[Insaneisfun]

because it is fun.

[neardood]

but(t) you could do something ten times as coll in the same time...

[glsluvs2snobrd]

I agree, and its even funner on the last day

[neardood]

Also, why does evry image reset the page scroll to the top? Is this some kind of cruel joke????!

[reedzilla]

I'm not entirely clear, given the pictures, what causes the weight to go up and complete the circuit from the battery to the alarm when the box is removed from the magnet. Is there a counterweight on the other side of the lever bar we can't see, or is the whole assembly on a springarm or something?

[photozz]

Yeah, I need to ad some clarification to the pictures. the switch is under the bar, it is holding th bar up on it's own, as it's just a momentary push button, kinda like a doorbell. the weight is not enough to push it down normally, but with the pull from the magnet, it's just enough to trip it.

[andrew101]

but y doesnt it go back off when put back?

[That Hurt This Time]

If you guys skipped step 1(i have no trouble beliving you did), its a magnetic switch that so when the box is moved away from the hard drive magnet, the magnetic field is broken, causin the bar to gu up and connect with the alarm.

[That Hurt This Time]

nvm that last comment i didnt see that photozz explained it. it would be gone but some glitch keeps it from being deleted .