Shocking Mouse Prank

Take a peek at the pictures for a basic schematic of the project and an overview of the setup.  I labeled the colors so you could keep track of what comes out on either end of the cable.

The basics are that the coil steps the battery's voltage way up but because we are using a small 6 V battery the current is low.  The mercury (tilt) switch activates the circuit and you get a shock.

BTW: Be careful with this thing.  I can't take any responsibility with what you do with it.  If you aren't comfortable with electronics and electricity then pass on it.  Do not use this on someone with heart trouble or a pace maker--that would not be funny.

The first time I made this project I used an old PS/2 mouse but now an archaic-looking manilla-colored mouse being placed at someone's desk looks pretty suspicious so I've wanted to upgrade it to a black usb optical mouse for some time.  The only constraint is that you'll need to be able to fit all the components inside the mouse housing.  On the other hand, there isn't that much to cram in there though.  Finally I ran upon a donor when I was cutting some cable (zip) ties and actually severed the mouse cord, oops.

In my case there was only one screw on the bottom side of the mouse to remove.  The front of the top cover hooked onto two tabs on either side of where the cord exits the case.  Be careful that you don't break them off because we're going to want to reassemble it in the end.

Go ahead and cut the mouse cord flush with the mouse's circuit board.  We won't re-use the mouse's cord because the wire is to lightweight to mess with (and is multi-stranded, which won't work for us).  When I made the PS/2 shocking mouse I actually was able to use the original mouse cord but I had problems with arching between the wires.  I'm going to keep part of the circuit board so that the mouse scroll wheel will remain in place, allowing the mouse to have all the feel and function as it did originally.

I then cut the circuit board in half width-wise to make room for the mercury tilt switch.  I kept the plastic lens so that the mouse looks totally real from the outside.  I clipped out almost all of the plastic tabs from the top and bottom of the mouse to make room for the surprise we're going to put inside!

We are going to run a thin wire on each side of the mouse, in the seam, right where your hand grips.  The back of the seam actually belongs to the top half of the mouse case.  This is important because we are going to drill holes (on each side) in that lip that overlaps inside the seam.  One hole for where the bare wire comes out of the case and another where it will go back in.

I used a 1/16" Dremel bit (just slightly bigger than the strand of wire I'm working with).   The bit I chose was actually smaller than any of the Dremel chucks I own so I had to use my cordless drill.

Follow the series of pictures (and the details included on each pictures) for the steps on where and how to drill the holes.

Take a 4-5' piece of the cable you are going to replace the mouse's cord with (this is the cable I used, except a grey version, which I had laying around) and expose the strands of wire on one end--be careful not to cut into the insulation of the individual strands because this might cause some arcing between the wires.  Pick the color you are going to use for the red wire in my diagram.  Strip enough insulation off the red wire so you can go out one hole and in the other and then have enough to bend the wire over inside the mouse so it stays in place.  The first time I made this mouse I actually used a paperclip for the contact wires, but that mouse had a bigger seam.  You'll also want to use a black permanent marker and paint the wire black to disguise it in the gap (versus having a shiny copper-colored wire) if you have a black mouse like mine.

The other contact wire will be done the same way but it isn't one of the wires connected directly to the new mouse cable (refer to the diagrams).  You can use one strand out of a different section of cable if you want.  In my case I had a piece of wire connected to the mercury switch already that I used.

Run the red wire (based on my diagram) out the first hole (from the inside).  I hot glued it in place before I went any further.  Shape the wire so it runs tight along the seam and then back in the other hole.

The second contact wire is the one that connects to one side of the mercury switch (refer to the diagrams for which side).  I already had some multi-stranded wire soldered to the switch so I won't be using the same kind of cable that we just used so I picked one of the individual strands of wire and then cut the rest of them off.

Insert the wire in the first hole and then glue the wire in place (see picture).  Shape the wire just like you did the first one and run it back in the second hold and bend it to hold it in place.

You will need to find a good place to mount the mercury switch.  The reason we are using a mercury switch is because we want the shocking mouse to be "off" when it is sitting still (and level) and we want the mouse to activate when it is moved (or better yet--when the unsuspecting user moves it back and forth quickly wondering why the cursor is not moving on the screen).  When the mercury connects the circuit---Zap!  You could actually fashion a motion switch that would be suitable for this project with an ink pen spring and a metal loop that would go around it--when the spring shook it would touch the loop, closing the circuit.  Let me know if you choose that method in the comments.

You'll have to play around with how you are going orient your mercury switch based on the space constraint but the more horizontal the better (verses orienting it top to bottom) because people tend to move the mouse back and forth (left/right), versus up and down, when they grab a mouse and move it (to wake the computer up from the screen saver).  You want to make sure the glass end of the switch is lower than the wire end because you want it off in the natural/flat position.  You'll also want to look at how the contact points are oriented inside the glass bubble because you want them pointing down.  See the pictures for the way I mounted mine (this picture is of the final project actually, because I relocated the switch after the first run).

Connect the wires as shown in the diagram and arrange them so there is clearance to put the mouse back together.  I used wire nuts to connect the wires because they are less work than soldering and heat-shrink tubing but they take up a lot more space and I had to hot glue them in place to keep them from getting in the way when I was closing up the case.

Follow the diagrams and color coding to connect everything on the coil and battery side.  You'll probably need to solder the wire to the output of the coil (center connection).  This was a pain originally because it was hard to get the coil side hot enough for the solder to stick.  I soldered this connection a long time ago and have just left the wire connected and re-attached it to my various projects.

I added a switch between the negative of the battery and the black wire in order to be able to shut off the mouse so I don't shock myself (anymore than I already have in testing the thing) and so I can transport it without running down the battery.  I placed everything in a box and added some cardboard to fill in the gaps so the parts don't roll around.  You definitely don't want to try taking this with you on a flight because you'd make the evening news!

Now it's time to test out the shocking mouse--ON YOURSELF.  I always test it before deploying it and that way I know it's working and I've experienced the deal myself that I'm going to subject someone else to.

This is nothing like a stun gun but they always make cops get stunned before they let them use it on someone else.

Be careful who you choose--this does shock you!  You have to test it out on yourself so get a feel for the surprise they'll get.  When they are not around, replace their desktop computer mouse with this one and then wait for them to come back to their computer :)  I don't have any desktop PC's at home so I had to take the picture with my mac.  At my office we used to look forward to the next new hire so we could initiate him into the group with a nice surprise!