Contact Switches

Contact Switch sensors are thin and robust and are usually placed inside the subject's shoe or glove for use as switches to indicate contact e.g. heel and toe strike or palmer contact.

FS2 Contact Switches have two force sensing resistor sensors (FSRs) that plug into a wireless Goniometer and for example, by attaching the Goniometer on the ankle, and the Contact Switches on the foot. It allows the researcher to co-ordinate the gait parameters with the dynamic movement of the ankle joint.

FS4 Contact Switches have four resistor sensors, each on 1.5 meters of cable which connects to one of the digital input ports of a wired interface such as the DataLOG, DataLINK or K800 Amplifier.

The programmable active edge of the input may be defined within the Digital Set up window of the Analysis Software. Digital traces of the contact switches may be displayed in one of two formats:

  • As separate traces that indicate logic 0 or logic 1
  • As trace pairs where two digital inputs are combined to produce a number in the range 0 to 3. In this mode, the weighting of the digital inputs may be changed; selecting 1/2 for example, results in trace 'A' contributing 0 or 1 to the final display and trace 'B' contributing 0 or 2
Screenshot #1 - contact switches used in gait analysis
Screenshot #2 - contact switches used in gait analysis

This pairing of the digital inputs would be used, for example, in gait analysis. With two contact switches placed on each foot – contact on/off will be registered. This synchronizes display of the gait pattern (heel strike-full foot-heel off-toe off) with other physiological parameters such as joint angles or EMG.