Hybrid Energy Systems Laboratory
Current requirements for various cell phone operations were measured by replacing the battery with a contstant 3.7 V from a power supply and monitoring the current output (Figure 1).
The strain gauge was calibrated using standard masses, and then was used to measure the keystroke forces delivered to a cell phone (Figure 2).
An accelerometer was used to measure the motion of the phone in all 3 directions when ringing an vibrating (Figure 3).
The piezoelectric devices were subjected to accelerations experienced by the ringing and vibrating phones using a shaker device, and their power output was recorded (Figure 4).