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Author Topic: Wiring a Opto-Isolated Relay to Arduino  (Read 3321 times)
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Hi, I was wondering if someone could help me interpret the instructions to wire up the following Opto-Isolated Relay (http://arduino-direct.com/sunshop/index.php?l=product_detail&p=156)

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NOTES: If you want complete optical isolation, connect "Vcc" to Arduino +5 volts but do NOT connect Arduino Ground.  Remove the Vcc to JD-Vcc jumper. Connect a separate +5 supply to "JD-Vcc" and board Gnd. This will supply power to the transistor drivers and relay coils.

So I understand the first part I connect 5v to the device. The second part has me confused though. I have a 5V wallwart so I connect the +5 to JD-VCC does that mean I connect the neutral off the wallwart to board ground? Or do I just ground that pin to the case?

I'm just a beginner as you can tell so go easy on me if it's a silly question  smiley

Thanks
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If you want complete isolation,  you will have seperate 5V supplies, one for the Arduino and one for the relay power.

Then you would connect an arduino output pin to the cathode of the drive LED, with VCC to a current limit resistor to that anode.

On the other side, you have pin 1 of the jumper field goes to the pin that goes to Pin 4 of the optoisolator.

If you  only have 1 wallwart, leave the jumper in. Having an optoisolatar and the relay seems like overkill to me. Most applications just drive the transistor to drive the relay.
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Thanks for the reply, I have two wall-warts but i'm still having a hard time following you. I quickly put this diagram to together to better help me understand (Don't laugh I only had paint).
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Not sure what the optoisolated relay is can you give a link. What you drew is not what anyone was expecting.
You need a ground going from the arduino into that optoisolated relay, I am not sure I understand what the right hand connectors are, and where is the load you are trying to drive with the relay?
Is it a mechanical relay or a solid state one?
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http://arduino-direct.com/sunshop/index.php?l=product_detail&p=156

Here is a bit more info too:
http://arduino-info.wikispaces.com/ArduinoPower

Thanks!
« Last Edit: August 14, 2011, 03:54:19 pm by Existence » Logged

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OK that is a rather unusual design you have it right apart from the 5V wall wart the positive output should be connected to the Vcc not the JD-Vcc
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Mike,
Having the seperate 5V go to the JD-Vcc means the Opto-receiver and the Relay are totally isolated from the Arduino Vcc.
Overkill for sure, but the design provides for that.
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Makes sense now, appreciate the help guys.
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Having the seperate 5V go to the JD-Vcc means the Opto-receiver and the Relay are totally isolated from the Arduino Vcc.
Overkill for sure, but the design provides for that.

I'm just trying to understand this a bit better. Since I'm not tying the grounds together does that mean the second wall wart is acting like ground for the +5v coming from Arduino? Or is it grounding through the Input PINS? I updated the pic as the last one was a bit confusing.
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