Hizuka007,
The reason your method doesn't work is because, with the magnet outside the coil, what tends to happen is that the changes in the magnetic field try to force the electrons in a single direction. Because the wire on opposite sides of the coil is essentially going in opposite directions, the small voltage induced in each segment of wire is cancelled out by the small voltage induced in the other side of the coil.
From the perspective of an electron that wants to travel one way along the wire, on one side the lines of force cross from the left, and on the other from the right.
If the magnet is inside the coil, those lines of force cross from the center to the outside of the coil. So looking from the perspective of the electron inside the wire, the lines of force all cross the same way. This means the small voltage induced in one segment of wire reinforces and adds to the small voltage induces in the next segment of wire, and so on.
You can do the same thing with a magnet outside a coil, but you would require a toroidal magnet (think donut or even a tube) that had the north pole on one face and the south pole on the other. You would then slide this up and down over the coil.
At the moment you're doing exactly not what we say, and while it may seem the same to you, it's a bit like we're telling you to press on the accelerator and you complaining that you've pushed the brake as hard as you can and the car's still not moving. Even if you can't figure the difference between the brake and the accelerator, we can.
