Folks! Here is a very interesting and innovative project which can adjust the amount of light entering your room automatically. It is called Self Adjusting Window Shade. The self adjusting window shade will automatically raise, lower, open, and close your blinds by itself. This system can either be controlled manually or automatically. A computer terminal acts as a remote to broadcast instructions to the window shade via RF. The system is also integrated with a special memory organization where information can be stored apriori like user’s previous settings, current environment conditions etc. This feature makes the project stand apart from other such patents which do not bear a memory table for automatic shade adjustment without human assistance.
The nodes in the memory table are set by using Chebyshev nodes given by the formula:
x_i = (a+b)/2 + (b-a)/2*cos((2*i+1)/(2*n+2)*pi)
Here two ATMega644 microcontrollers are employed; one at the computer’s end and another at the window’s end. The second MCU contains two modes of operation: automatic and manual. The motion of the window pane is controlled by a stepper motor. User input can be taken at the computer terminal and transferred to the first MCU via RS-232 communication. RCT433 transmitter is then used to send the manual input to the second MCU which drives the motor through motor driver ULN2003A to adjust the window pane accordingly. The window blinds are moved up and down using 2 PF35T-48L stepper motors.
Obviously there has to be some mechanism to sense the surrounding temperature. Temperature input is taken from LM34 sensor. It is amplified by a gain of 2 using the LM358 for greater accuracy before entering the ADC in the MCU. The current room temperature is then used to calculate the settings for the shade.
The automatic window pane sounds really exciting and making one for my room will be great fun indeed besides a healthy electronic exercise.
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