In this project I am going to show you how to make a dark sensor using a single transistor and some few resistors in just 3 simple steps .
here is my video this is my old dark sensor
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Things You Need
1) 1x BC547 transistor
2) 1x 220 k resistor
3) 1x 330 ohms resistor
4) 1- small perf board
5) 1x led (any colour )
7) 9v battery
8) battery clip
9)ldr(light dependent resistor )
1) soldering rod and wire
2) wire stripper
Step 2: Getting Started
solder the transistor on the perf board and solder one wire of the ldr to the emitter and other to the base , solder the negative wire of the led to the base of the transistor with a 330 ohms resistor and also solder 220k resistor with the one side of the 330 ohms resistor
Step 3: Finishing Touches
I have also used a SPDT switch it is optional I have used to pin headers as the connectors for the power .