Darkroom timer

A timer for switching power to and from a unit, comprising:

• a. actuator means;
• b. digital means responsive to said actuator means for providing control signals;
• c. coupling means for providing the timer with a periodic signal having a first characteristic frequency;
• d. clock means responsive to said coupling means to produce a series of pulses having a characteristic frequency related to said first characteristic frequency;
• e. counter means adapted for receiving a desired selectable digital value, said counter means being responsive to said control signals from said digital means to count pulses from said clock means and produce an output when a digital value entered into said counter means has been counted;
• f. programming means for entering a desired selectable digital value into said counter means;
• g. switch means responsive to said counter means for switching power to and from the unit as a function of the condition of said counter means;
• h. audio means responsive to said clock means for producing a periodic audio signal related to said first characteristic frequency;
• and
• i. display means coupled to said counter means for displaying the value stored in said counter means.