This instructable is about making an LED flashlite with light / dark sensor. it turns on automatically when its dark and turns off when its day.
Step 1: Step 1: Collect the parts:
Here's what you will need:
1. LDR (Light Detecting / Dependent Resistor)
2. NPN Transistor (I have used BC 547)
3. 9 volt battery
4. 9v battery lid
5. Four LEDs, 5 mm bright white
6. 1/4 watt, 100 ohm resistor (per LED, so 400-500 ohms for 4-5 leds)
7. 1/4 watt, 10k ohm resistor (per led)
8. small piece of PCB to mount the assembly.
Note: Instead of items 6 & 7, you can straightaway use a single 500 ohm & 50K (or 100k) resistor each, if you are going to use only 4 or 5 leds....
Additional tools like, solder, solder wire, hot glue or its equivalent.