Making the Bi-Directional Flex Sensor:
This entire sandwich is inserted into the heat shrink tubing, see figure 7. The base of the sandwiched materials is shown in figure 8, just before it is inserted completely into the heat shrink tubing.
You are almost finished. At each end of the heat shrink tubing place a small amount of clear silicon sealer, see figure 9. Allow the sealer to dry according to its directions, usually around twenty-four hours.
Testing the Bi-Directional Flex Sensor:
Set a VOM meter to read ohms. The sensor we built had a nominal resistance of approximately 20K ohms, see figure 10. As the sensor is bent in one direction the resistance decrease in proportion to the bend to approximately 2k, see figure 11. Bending the sensor in the opposite direction also decreases the resistance in proportion to the bend to 2K ohm, see figure 12.
The sensor is also pressure and force sensitive. So pressing down on the sensor will also decrease it resistance. The basic sensor can be modified in size and shape to fit custom applications. The resistive material may also be modified to obtain different resistances and characteristics. Most materials are easily obtained from electronic sources. Images will supply the following materials to get you started. Flex Sensor Components