Sensor Characterization in terms of Electrical Output ( Open - Circuit Voltage, Short - Circuit Current and Output Power) through Longitudinal Displacement
We carried out experiments to characterize our sensing interface’s electrical output in terms of short circuit current (Isc) current, open circuit voltage (Voc) and electrical power for various input frequencies and longitudinal displacement (stretch). First, customized plastic brackets were constructed to hold the sensing interface between the linear motor and Newport 462-XYZ-M Linear Stage. Afterwards, the sensing interface was aligned parallel to the ground and, firmly fixed in a straight line between the laboratory equipment. The acceleration, deceleration and displacement of linear motor arm were controlled through computer to simulate different frequencies and longitudinal displacements of interaction. The electrical output from the interface was measured through Keithley electrometer. The procedure was carried out for two sensors with different stiffness. The following results were obtained:
Observation: Open Circuit Voltage
On the one hand two different interfaces show some similarities in open circuit voltage: 1. Over the given range of frequencies, open circuit voltage is observed to almost remain unchanged at 5 mm displacement, and 2. With increasing displacement, open circuit voltage shows approximate linear relationship with frequency, but this linear trend is noticeably broken at high displacement of 20 mm and 25 mm. On the other hand, there are prominent differences in the electrical response to frequency and displacement of interactions. For all displacements and frequencies the softer interface generates greater open circuit voltage as compared to the stiffer the alternative. This indicates that the softer interface is more sensitive to stretching interaction. Furthermore, the approximate linear relation between voltage and frequency depicts steeper slope for the softer interface, which suggests that for the tested displacements, sensitivity of the soft interface to frequency, improves with increase in displacement.