Hello, for the first "instructable" I wanna build a LED lamp or flashlight which will turn on at some points of darkness.
Here is the list of what you need!
1- Some Smile. :-)
2- BC547 Transistors(x2)
3- 1N40001 or 1N40007 Diod (x1)
4- LDR (Light Dependent Resistor) (x1)
5- Some Resistors (1k and 0.5k) or 10k Potentiometer(The More, The Better) for making it more accurate.
6- 5 Volts Relay(x1)
Step 1: The Circuit
Here is the circuit. Try wiring it first on Bread Board, then solder it on another boards to sure you debug your stuff. For checking it just put your finger on LDR, your relay must connect or disconnect with a click sound. if you found anything OK but no click from relay, change the 330 ohms to a bigger resistor, I used 2k and was good.
Step 2: Share Yours
The last part is the result. Pictures showing mine. the last one is in darkness. These LEDs found from an old flashlight which my school gave it to me as a prize six years ago, but anyway, that's it!
A Persian article is available on my website.