Automatic Night Light





Introduction: Automatic Night Light

In our busy life, many of us forget to switch off the light morning. By using this simple circuit, the light will "automatically switch on" in night and "automatically switch off" in morning.

Step 1: Components Needed

1. Bread Board
2. LDR (Light Dependent Resistor)
3. Relay 6 volt DC (SPDT)
4. Diode 1N4001
5. Resistor 1K and 330R
6. Transistor BC547 (2)
7. Bulb

Step 2: Setting the Circuit

Connect one end of the LDR with Vcc and another end with one end of Resistor 330 ohms. Connect the another end of resistor with Ground.

Step 3:

Connect LDR with Base pin (i.e., 2nd pin) of Transistor BC547.

Connect 1K resistor with Vcc and another end with Collecter pin (i.e., 1st pin) of Transistor BC547.

Connect the Emitter pin (i.e., 3rd pin) of Transistor BC547 with Ground Voltage

Step 4:

Connect the Collector pin of Transistor BC547 with Base pin of another Transistor BC547

Connect the Emitter pin with Ground Voltage

Step 5: Introducing Relay

Connect cathode side of Diode 1N4001 with Vcc.

Connect anode side of same Diode with Collecter pin of Transistor BC547.

Connect 'A' terminal of 6volt (SPDT) relay with Vcc and 'B' terminal with Diode's anode side.

Step 6: Setting the Bulb With Relay

Cut any one of the two terminals of the Bulb's wire in order to connect it with the relay.

Connect one wire with 'POLE' and another with 'NO' of the relay.

Step 7: Adding 6Volt DC

Connect the circuit with 6volt DC.
Don't switch on the circuit now.

Step 8: Adding 230 Volt AC

(Now you are going to play with 230 Volt AC current, this is the risky step in this Project, please do this with caution. Or otherwise please don't continue.)

Connect the Bulb with the 230v AC.

Step 9: Its Ready Now...

Now switch on the power supplies of the circuit, both 6v DC and 230v AC.

If your circuit is in dark, the Bulb automatically lights

If your circuit is in light, the Bulb automatically switch to off.



  • Clocks Contest

    Clocks Contest
  • Creative Misuse Contest

    Creative Misuse Contest
  • Water Contest

    Water Contest

14 Discussions

what changes should i do if i have to use 9v battery as supply?

can this automatic night light drive up to 1000w bulb?

please send me,
modified diagram,

i want use only ac source,
this circuit correction what is?

like as,
power source ac on,
this light auto on dark,
pls reaply

i have a modified version of night light circuit

Hi bfyzal:
Nice project, Will you please guide me, how do I connect AC supply to the bulb?

i think this is the circuit diagram


Nice Job, but you have to keep the lamp away from the LDR! :)

One transistor is enough.