Pressure sensor is an element that changes its parameters according to changes of pressure that is put on it. Today I will present how to build it by using common and cheap materials like chewing gum and pencil.
In my implementation when pressure increases, then electrical resistance of sensor decreases. Main part is elastic conductor that is in between of two electrodes connected to multimeter that indicates resistance between them. Minor role plays here elastic rubber around of conductor - it helps bring element to its original shape.
Mentioned element contains a lot of small conducting parts. When pressure increases, those elements are closer to each other, so the overall resistance of element is decreasing. When pressure goes down, element returns to its original shape and resistance.
I made experiments with two conducting elements. The first one was silicon glue mixed with graphite powder made from crunched pencil fill. Below is picture of paste made from silicon glue and graphite.
The second attempt was also with graphite powder, but instead of silicon glue I used chewing gum. Below is picture of paste made from chewing gum and graphite.
Below are couple of pictures of sensor assembled with silicon glue. Its resistance was in range 600-700 Ohms.
Here are pictures of sensor with chewing gum, its resistance was it range 600-900 Ohms.
If you would like to made this by yourself, please remember that its parameters will vary according to shape of electrodes, size of used conducting element and its materials. Those parameters will also probably change with time.