a standard digital display alarm clock is provided which is driven by a 1 . 5 volt dc power source . a two - tone alarm device , whose sound level is adjustable from 60 db to 100 db , is electrically wired to the clock and sounds when the clock attains a predetermined time . the power for the alarm device is supplied by either a 9 volt dc source contained within the clock or a 12 volt dc automotive cigarette lighter . the clock is provided with an intermittent alert feature which will cause the alarm to sound every four minutes for an indefinite amount of time and requires operator input to deactivate .