Being naive to hardware & electronics, I might missing something silly here.

Here is my setup to able turn on/off bulb using iOS app and node.js as backend -

Is any important thing missing here? or is there relay capacity issue?

Any help would be appreciated. Thanks

snapshot of setup 1 snapshot of setup 2

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    Hello and welcome! The ULN2803 driver circuit (as in the first linked relay board) should work with 3V3 from the Pi. However the images show different relay boards and possibly different drivers, check those first. And please mind the potential dangers of electrocution when playing with mains voltages! – Ghanima Jan 20 '16 at 7:40
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    Where are you getting the 12 V power for the relay? – goldilocks Jan 20 '16 at 9:57
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    You have 3 wires going from the pi to that relay -- ground, 3.3V control, and 5V power. The last is connected to the supply pin on the relay, which is explicitly described as "CONTROLLABLE with 5V or 3.3V SIGNAL. Power supply : 12V (Vcc)". – goldilocks Jan 20 '16 at 10:21
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    What do you think "Power supply : 12V (Vcc)" means? How much voltage have you supplied in relation to this? The fact that it worked with a lower voltage connection does not matter. The point is it does not work now. I don't know enough about to relays to explain why, but I can read. – goldilocks Jan 20 '16 at 10:34
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    SAFETY FIRST! You're poking wires into a socket! And your Pi's ground wire is literally millimeters from mains! Just a public service announcement. – PNDA Jan 20 '16 at 12:48

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