Why is my circuit working only when I touch it? I have connected digital pin 2 of arduino to the circuit as shown:

The problem is that the LED is not turning on normally its only turning on when I touch anything on collector side of circuit. What seems to be the reason? Seems like grounding problem as its turning off when I don't touch my legs to ground.


Thank you in advance.
Sounds like you have guessed it: although it's very hard to say from those photos, it doesn't look like you have the circuit grounded.

Connect a ground from the Arduino to the black wire from the battery.