The function of smart street light can be controlled by a simple Transistor. It is a very interesting project, and it is very simple to construct. Here in this topic i'll explain how to make it without any IC and microcontroller.
Not using a microcontroller results in smaller form factor and reduces costs as well.
- NPN transistor(BC547)
- AC / DC source to swich on the bulb.
- 5 volt relay.
- power supply
Step 1: Connect Components
Connect the transistor in voltage divider bias condition.
Here the proteus diagram is showing that you've to use two 5 volt power supply. You can use only one 5 volt source to make this circuit, so follow the breadboard circuit. Connect transistor base to the LDR as it is connected in above pictures.
Step 2: Connect the RELAY
In RELAY there are 5 pin. The [+ve terminal of DC circuit ] and [- ve terminal of DC circuit ] is allotted for relay switch on purpose, which is coming from the transistor.
Just follow the breadboard circuit. The yellow wires indicates which pin you've to connect to the relay for giving supply 5 volt to relay.
COMMON and NC will link the main supply + ve terminal of supply voltage which is used to turn on the bulb.
and the supply -ve terminal will directly connect to the ground of supply voltage.
Step 3: Connecting Power Supply
Now give 9 volt dc supply to the circuit and give AC supply to connect the bulb.
When you cover the LDR (devoiding of light/Evening time), the bulb will glow.
When the light falls on the LDR (Morning time), the bulb will not glow.