Staircase Light With Auto Switch-Off

Description

Auto Switch-Off Staircase Light block is a power supply kit in which the input is 230V AC which is step down using the transformer (12-0-12). The 12V ac input is fed to the bridge diode to gives 12V pulsating DC. This DC voltage is filtered through the capacitor to remove the ripples. The filtered DC is fed to the 7805 regulators to fetch +5v regulated output.

In the Staircase Kit, the light with an auto switch is adjusted so that when the person comes near the stair it is pressed. This press of the switch sends logic low to the trigger pin2 of the LM555 IC which generates an active high output on pin 3. The IC is used in a mono-stable state. The value of the time for a high pulse on each trigger at the input is dependent on the value of the resistor and the capacitor. The output from the LM555 drives the ULN2803 IC (it act as a current amplifier to meet the current requirement to drive the relay).

Automated Staircase Light is an inverted IC means when input is low output is high and vice versa. This IC drives the relay to activate the light which is a DC bulb. The relay acts as an electromagnetic switch to switch the high voltage to activate the DC bulb and activate the DC supply across the bulb.