Thin Film Pressure Sensor Flex/Bend Sensor SF15-600 10kg Resistance Type Force Sensing Resistor FSR Sensor Force Sensitive Resistor: Amazon.com: Industrial & Scientific
Interface Flex sensor with Arduino - Measure Bent Angle or Deflection
Flex sensor - Wikipedia
Short Flex Sensor : ID 1070 : $7.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Thin Film Pressure Sensor Flex/Bend Sensor SF15-150 Resistance Type Thin Film Pressure Sensor Force Sensing Resistor Force Sensitive Resistor: Amazon.com: Industrial & Scientific