automation - light control

[malini]

Hi!
I'm trying to control an LED(5 mm LED) from the relay using raspberry pi 2 board. I have an 8 channel 5V relay. I also have a 9V dc battery for the LED. I'm a little confused with the connections regarding the relay because i don't want to damage my Pi.
So one side of the relay will be the raspberry pi and the other side will be 9V battery and the led?
I have attached an image file showing the connections. Is it alright?

[Burngate]

Is it alright?

Looks good - apart from the LED needing a series resistor (it controls the current through the LED, and without one, your Pi won't mind, but you'll go through a lot of LEDs while you're playing)

[Laurens-wuyts]

What realy are you planning to use (link)?
You'll probably also need a flyback diode across the relay.

Laurens

[Burngate]

... a flyback diode across the relay.

It looked to me that since the "relay" has 3 connections - Vcc, Gnd, In1 - it includes a driver circuit, which would have a fly-back diode built in?

[Laurens-wuyts]

It looked to me that since the "relay" has 3 connections - Vcc, Gnd, In1 - it includes a driver circuit, which would have a fly-back diode built in?

Well, it could be, but as long as we don't know the specific relay, we're not sure (better safe than sorry )

Laurens

[Burngate]

True

[malini]

https://www.google.co.in/search?q=8+cha ... auDqY6M%3A

this is the link.
I guess the diode and everything is built in right?

[malini]

and yes.. I am using a resistor with the led.

[malini]

the relay is just clicking but the led isn't lighting up! And sometimes when i terminate the program, the relay still keeps clicking. Why so? can someone please help?