Relay won't switch

Hi all, I have a problem with this relay http://www.ebay.com/itm/5V-Two-2-Channel-Relay-Module-With-optocoupler-For-PIC-AVR-DSP-ARM-Arduino-/181026509345
I’ve just connected to my arduino uno board, and using this code:

int pinRelay = 8;

void setup() {
  Serial.begin(9600);
  pinMode(pinRelay,OUTPUT);
}

void loop() {
  digitalWrite(pinRelay,LOW);
  Serial.println("Light ON");
  delay(2000);
  digitalWrite(pinRelay,HIGH);
  Serial.println("Light off");
  delay(2000);
}

I thought that I can control it.
The led on the relay board turn on and off well, but I can’t hear the sound of the coil, and when I’ve tried to connect a supply to the COM and NC connection, nothing happenend.
Is the relay broken or I’m missing something?

when I've tried to connect a supply to the COM and NC connection, nothing happenend.

That created a dead short of whatever supply you are using.

It's difficult to determine what the connections are to the relay module so I can't determine if it is correct.

What current is required to energize the relay?

I believe there is a jumper on the relay board that determines where that board is powered from. You may have the jumper incorrectly set.

  • Scotty

Thanks for the answer, I'll try to explain the connections. The relay board require 5V so I supply that with my arduino board, connecting 5V pin to vcc, and arduino Gnd to relay Gnd. The relay have the jd-vcc short with the vcc. I tried connecting a 12V 1A transformer to the Com for use a led (just for try). The hot line, the + wire, is connected to com, the Normally closed is connected to the led.

I'm a totally idiot...I have a 12V relay and not a 5V relay...I just have to supply that with a 12V power supply...all works!

Narsil22: I'm a totally idiot...I have a 12V relay and not a 5V relay...I just have to supply that with a 12V power supply...all works!

Welcome to the club. I'll PM you with details on where to send your dues. ;)

Narsil22:
The relay board require 5V so I supply that with my Arduino board, connecting 5V pin to vcc, and Arduino Gnd to relay Gnd. The relay have the jd-vcc short with the vcc.

You can only supply the (5 V) relay board from the Arduino Vcc if you provide a 5 V power supply to the Arduino board. USB power may work but attempting to power it through the on-board regulator is asking for heartache.

If you didn't find the solution already, try this:

http://creatgraphy.com/04/2017/technik-kram/arduino/use-it-right-8-channel-relais-board-chinesesainsmart-version-185/

Its explained in this post. You have to disconnect the Jumper GND and VCC... Be careful ! the relays need probably more power.

Paul__B:
You can only supply the (5 V) relay board from the Arduino Vcc if you provide a 5 V power supply to the Arduino board. USB power may work but attempting to power it through the on-board regulator is asking for heartache.

I have a similar relay Paul, and the singals are fed directly from the digital pins on my UNO. Should I not do this? (sorry to hijack your thread Narsil22!)