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This article was posted to the Usenet group alt.hackers in 1995; any technical information is probably outdated.

Re: Hacker FAQ (please comment and help fix)

Article: 7749 of alt.hackers
From: (Joel A. Jimenez)
Newsgroups: alt.hackers
Subject: Re: Hacker FAQ (please comment and help fix)
Date: Mon, 01 May 1995 21:21:58 -0600
Organization: the Ohio State University
Lines: 35
Approved: by me :)
Status: RO

> ObHack:
>    Wiring a photodiode into the joystick port of an Apple ][ and hooking
> it up outside the door, so the computer can detect people walking up to
> the house.  No practical use that I could think of (there are much better
> ways of doing burglar alarms), but it was fun for parties.

Reminds me of something I did as a kid when my brother and I were
fighting.  I don't know why, but my older brother and I had gotten into
the habit of ambushing each other with either waterguns or whippersnappers
or whatever.  Anyway, I got my brother especially good one day and he
promised me "in your sleep", meaning that he was going to come
into my
room and do something to me while I was sleeping.  Well, I certainly
wasn't going to stay up all night so I had to come up with something.  It
was summer and I was sleeping in the basement.  Trip wires weren't ideal
because I'd have to put them on the stairs to catch him and I really
didn't want to hear my mother or father falling to their death because I
laid a trip wire.

So, I had an old radio shack metal detector and a wall socket deal that
turns the lights off when it gets dark at night.  So, I cracked open the
wall socket deal and pulled out the photodiode.  I opened up the metal
detector and wired the photo diode inline with the adjustment resistor on
the detector.  After fiddling with the resistor a bit I got it set where I
wanted so that the detector would sound just when light hit it.  I banked
that my brother's curiousity would have him shine his flashlight on the
strange looking contraption I'd set in the middle of the room.  (I knew he
wouldn't come without a flashlight, it's just too damn dark in that
basement to get around without one. :)

Anyway, it worked.  I was prepared with a loaded water pistol when I went
to sleep and I got him good when he tripped the alarm.

                                 happy hacking,

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