How to make simple "motion" sensors

Step 5 Second type - construction

Place the ball to the tube and make sure it won't fall out from on side of it (glue, solder or plug there something - or hit it with a smaller hammer). My tube was cut in a way that it wasn't an issue. Remove the insulation from the ends of the 1st wire then make small circle on one end. Then make a shape from the whole wire according to the shape of the tube (as seen on the 2nd pic). It will hold itself in place. Place it on the tube (like on the 3rd pic) - you know, the small circle must be on the side which is not plugged... Make sure there is no el. contact between the copper wire and the tube. Glue it the wire to the tube as it is now.