I have window blinds that are raised and lowered with an electric motor (220 VAC 50 Hz). I want to raise and lower them using a time clock. The problem is that the time clock will completely open or completely close the blinds whereas I want to be able to raise or lower the blinds to varying heights. If I use a 555 timer circuit to vary the time the motor is switched on (for a period between 1 second to 1 minute) I have the problem that the time clock switches on for a minimum period of 15 minutes whereas I need a single pulse to operate the 555 circuit. Anyone have any ideas how I can solve the problem?