Looking for some beginning DIY projects in electronics? Then you have come to the right place. In this project, I'm sharing my first electronic project, which I teach to every new one in electronics.
If you are new to electronics, you are welcome to this place. Let's learn! Only for beginners, if you are an expert skip this project.
Step 1: Beginning
First, let us learn about the electronics components used for this project:
- Resistor: Used as what its name says (resistance). It provides a potential difference in a circuit.
- Potentiometer (pot meter): Using this we can change or adjust resistance by turning the knob or moving it.
- Transistor (those 3 legged thingies): Used as an amplifier, automatic switch etc., (in this project we are using it as an automatic switch).
- LDR (Light Dependent Resistors) also known as cadmium cell: LDRs or Light Dependent Resistors are very useful, especially in light/dark sensor circuits. Normally the resistance of an LDR is very high, sometimes as high as 1000000 ohms, but when they are illuminated with light resistance drops dramatically. For more details visit this site.
- LED (Light Emitting Diode): Gives out light when electricity is applied to its respective electrode.
Step 2: Let's start building
We are going to make a simple automatic light which automatically lights up when it's dark.
Step 3: Things you need
They are available at less than 3-4$. Soldering iron and prototyping PCB is optional. I first made it without soldering.
Step 4: Circuit diagrams
Gather everything and carefully follow the circuit diagram.
Note about potentiometer: Connect the middle and any other one pin of pot meter, leave other (as in picture 2 in this step) and connect it to the circuit.
Step 5: Transistor
NOTE: A transistor has 3 legs middle one is the base (B) and other two is the collector (C) and emitter (E) respectively as in the picture for this transistor. You may be confused at this point if you are a beginner (I was also confused at first, I learned from my mistakes). That is why I remind you learn from mistakes, and don't give up if you fail, try till you win (at least that is what happened to me). That is what the Edison did before he invented the light bulb. So NEVER EVER GIVE UP.
Step 6: You have finished
All done. Ready to test. Connect the circuit to a 9V battery positive and negative respectively. Please forgive me for my images, if you didn't understand it. What do you expect, first tries, that too from a kid who does not have a soldering iron.
Step 7: Let's test
Take the circuit to a dark place or hide LDR with your finger and switch on the circuit. The LED should light, if not adjust the pot meter (turn it or move it). After the LED glows take your hands away from LDR or come back to a lighted area, the LED should turn off, if not again adjust the pot meter. If it all works as said, it's ready.
If not rewire the circuit or find the fault (don't give up). Frequently adjust pot meter for better performance. You're done, when its dark LED glows automatically. When it is bright it switches off automatically. And don't forget to improve my tutorial. I will be back soon with another tutorial.
This circuit is not that much powerful to work with a relay. If you want a circuit which works perfectly with a relay just like this one. I have tried the 555 one but it is a little bit laggy. If you want a more powerful circuit you can visit this tutorial.