Which of the following is not among the sensors commonly used in assistive devices as listed?

• A. Force sensors
• B. IMUs
• C. Pressure mapping sensors
• D. GPS sensors

Answer: (D)

Sensors in assistive devices are chosen to directly capture how a person interacts with the device or how the device moves, so the data are immediately useful for control, safety, and comfort. Force sensors measure the contact forces at grips, supports, or buttons, enabling proportional and safe actuation. IMUs provide information about motion and orientation, which helps in detecting movement patterns, gait, or postural changes. Pressure mapping sensors show how pressure is distributed across seating surfaces or contact areas, helping prevent pressure injuries and improve fit.

GPS sensors, while great for location tracking outdoors, don’t offer the immediate, local feedback needed for most assistive-device functions. They can struggle indoors, require more power, and don’t directly inform grip, movement, or contact quality. That’s why GPS sensors are not among the commonly used sensing modalities in typical assistive devices.