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Battery-powered Night Lamp
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Schematic design of Battery powered night lamp
Part List :
Capacitors	Resistors
C1       =  100 nF / 63V Polystyrene C2       =  220 μF / 25V Electrolytic Semiconductors IC1  = 7555 or TS555CN Others. B1   = 1.5V Battery (AA or AAA cell, etc)	R1,2 =    1M Ω ¼W R3    =   47K Ω ¼W R4    =  Photoresistor (any type) Diodes D1    = LED Red 10mm (Ultra-bright)
Notes
This circuit is usable as a Night Lamp when a wall mains socket is not available to plug-in an ever running small neon lamp device. In order to ensure minimum battery consumption, one 1.5V cell is used, and a simple voltage doubler drives a pulsating ultra-bright LED: current drawing is less than 500μA. An optional Photo resistor switches-off the circuit in daylight or when room lamps illuminate, allowing further current economy.  This device will run for about 3 months continuously on an ordinary AA sized cell or for around 6 months on an alkaline type cell but, adding the Photo resistor circuitry, running time will be doubled or, very likely, triplicated.   IC1 generates a square wave at about 4Hz frequency. C2 & D2 form a voltage doubler, necessary to raise the battery voltage to a peak value able to drive the LED. IC1 must be a CMos type: only these devices can safely operate at 1.5V supply or less. If you are not needing Photo resistor operation, omit R3 & R4 and connect pin 4 of IC1 to positive supply. Ordinary LEDs can be used, but light intensity will be poor. An ordinary 1N4148 type diode can be used instead of the 1N5819 Schottky-barrier type diode, but LED intensity will be reduced due to the higher voltage drop. Any Schottky-barrier type diode can be used in place of the 1N5819

Source : Electronics Lab