How to connect V 4-Channel Relay Module to Arduino

Hi I purchase V 4-Channel Relay Module Low Level Trigger with Opto coupler for Arduino What kind of External power supply need to this relay. It work with 5 volt but how much current need ?. And how do I connect it together with Arduino board ? the link is http://www.ebay.com/itm/121311386008?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

There are more than one model of 4-channel relay modules available in the world.

At least two, I should think.

please post a link to the part.

look at the relay. it should have a printing on it with the model number. google that to find the voltage of the coil.

relays that we use have 3 separate possible voltages. the contacts have one, the coil needs one and the control signal has the third.

the relay has contacts. these are rated for very high voltage and offer a range of voltages. but usually only list the maximum allowed. the voltage listing is combined with a amp rating. this comes in 3 forms. one is resistive, as if you are connecting a resitive heater like on your oven or coffee pot. another is motor hp and the third is inductive. use the one that applies to the thing you are turning on and off.

the second voltage and one we are more concerned about is the coil voltage. for most of the ones we use, it is either 5 volts or 12 volts. but, it could be 24, it could be AC or DC, and in AC, it could go up over 460 volts. But, we usually buy from e-bay and get either 5 or 12 volts coils.

the coil is isolated from the contacts. you select the contacts for your load and the coil for control voltage.

the third voltage is what we use from the Arduino and that is 5 volts. many of the relay boards have optoisolators to allow you to use 5 volts. the optoisolator is an LED, so you treat it as an LED. that means a max of 20ma, with something above 10mA to make sure it is working. if you are outside of that range, read the data sheet of the opto. some can take lots more, some lots less.

I said all that to ask how you are lighting the LED that is the opto ?

you can supply 5v and MAY need to use a resistor, and the opto is connected to ground and will light when you supply the 5 volts. or, the 5 volt is connected all the time and all you do is complete the circuit and bring the LED to ground.

for the one an two relays on a board, one typically sends 5v to turn it on and removes the 5v to turn it off. for the 8 and 16 relay boards, they are often supplied with the 5v and one brings the opto to ground to turn it on.

the 4 relay modules ? need to see the data sheet.

so I end with my opening statement.

please post a link to the part.

katanyeheskel: Hi I purchase V 4-Channel Relay Module Low Level Trigger with Opto coupler for Arduino What kind of External power supply need to this relay. It work with 5 volt but how much current need ?. And how do I connect it together with Arduino board ?

If it's typical of many Asian e-bay type relay modules the hook-up would be as follows:

  1. ground to ground
  2. 4 relay channel input pins wired to 4 arduino digital output pins
  3. Board Vcc power to arduino 5V pin, 4 relay coils won't 'overload the Arduino board's 5 vdc.
  4. The board my have a movable jumper for power, be sure it is proper position to be powered from Arduino.
  5. As you stated in your coding a digitalWrite(pin#,LOW) will turn on the relay channel.

Good luck

the link to the
5V-4-Channel-Relay-Module-Low-Level-Triger-with-Optocoupler-for-Arduino

http://www.ebay.com/itm/121311386008?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT