Download Smart Alarm Clock

Lighting Control
Another means of waking the user that the Smart Alarm Cock uses is controlled
lighting. The controlled lighting works in much the same way as the buzzer control. As
can be seen from Figure 2, when the alarm clock first reaches the preset alarm time, the
unit enters Alarm Stage zero. This corresponds to a low level lighting. If the snooze
button is pressed, the Alarm Stage is incremented by one, and after a “snooze period,” the
alarm begins to wake the user with medium level lighting. If the snooze button is pressed
again, the Alarm Stage is increments by one again. After another “snooze period,” the
alarm attempts to wake the user with a higher intensity lighting.
These three stages of the alarm make it necessary to have a lighting that has three
levels of intensity. This is accomplished by having 3 separate outputs from the PIC going
to the light. This is similar to the buzzer control, but the goal of the design is to allow the
user to plug any general lamp into the alarm clock unit. This is so that the user does not
have to purchase a separate lamp specifically for the alarm clock. There are two outlets
mounted in the alarm clock unit. These outlets are controlled by electromechanical relays
and voltage divider circuits. To minimize the number of output pins on the PIC, the same
voltage divider circuits are used for the buzzer and lighting control. The difference
comes after the divider circuits. A schematic of the Piezoelectric Buzzer and Lighting
Control is given below in Figure 20.
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