U will need tape, pencil eraser from its back, spring and wires
Solder a wire to the to the spring. The rear of the wire(away from the spring) is one terminal of the sensor. Make a hole concentric to the circumference of the cross section of the eraser and insert another wire such that it comes out from both sides of the eraser
Solder longer wires to the spring on opposite side. These are the touching feelers
This is what it will finally look like. The rear wires are the terminals. Some of you must be wondering what will happen if both the sensor leads comes in contact with a surface simultaneously. Well, I say that the probability for that is low. If you are not satisfied with the design you can use just one feeler, or configure the feelers such that both don't make contact simultaneously. If you intend to make 2 sensors for one robot then one feeler for each sensor makes more sense.
