A solar cell and method of fabrication are disclosed. Sensors determine a real-time temperature at the multifunctional stroller and are coupled directly to the timer-actuated switch. The process fluid tubing is a generally chemically inert tubing. The information is then used to drive the backup program. So-called play lists can be created. The authentication unit includes a near-field reader configured to read a first identification feature based on inherent disorder, and a far-field reader configured to read a second identification feature, such as a bar code, optical characters, or an RFID tag.