User manual

FSR™ Integr
ation Guide
Figure 2: FSR Ink Micrograph
The conductive traces are typically screen printed from s
ilver poly
mer thick film ink.
However, these traces may also be formed out of gold plated copper as on flexible or
standard circuit boards (FPC or PCB).
Force may be applied to either substrate. One of the exterior surfa
c
es typically includes a
mounting adhesive layer to allow mounting to a clean, smooth, rigid surface.
2.2 Force Curve
A typical resistance vs. force curve is shown in Figure 3. For interpretational
convenience, the data is plotted on logarithmic scales. This particular force-resistance
curve was measured from a model 402 sensor (12.7 mm diameter circular active area). A
silicone rubber actuator with a 4 mm spherical radius tip and 60 Shore A durometer was
used to press on the FSR).
The “actuation force” or turn-on threshold is typically defined as the force required to
bring the sen
sor from open circuit to below 100k resistance. This force is influenced by
the substrate and overlay thickness and flexibility, size and shape of the actuator, and
spacer-adhesive thickness (the size of the internal air gap between membranes).