4 relay module high/low level trigger

Hello can someone teach me how can i use this kind of relay module? and how to program this?
i did my best to trigger atleast one of this relay but still not clicking

Welcome to the forum

Please post the sketch that you tried and a schematic of your project. A 'photo of a hand drawn circuit is good enough. How is the project powered ?

Something like this sirr

not something.
Show your EXACT schematic.
Show real pictures so we can see what you have wired - each single wire must be visible. Use reasonable wire colores like red for 5V, brown or black for GND, other colors for D9.
Show your code your have tried

There are jumpers on the board in your 'photo that are not in the "schematic"
Details matter

ideally you would find the spec from the vendor (unless you really know what you are doing, it's generally not recommended to purchase such devices which do not come with full documentation and a schematic).

It's all the more important if you are new to this and you are going to connect an High power load... Be careful, many people do get killed by High current every year. Ask for assistance from an electrical engineer and take precautions.

Typically - but NO guarantee - it would go like this:

The pair of pins you select for your circuit will make the relay Normally Open or Closed. Usually there is an indication on the board (NC = Normally Closed, NO = Normally Open)

Depending on the board / coil current needs, it's usually advised to not draw the 5V/GND input from your Arduino 5V pin but to power this separately (in parallel for example) and join the GND of this power with the Arduino GND.

The command pin is an Arduino pin set as an OUTPUT.

You also have some jumpers that seem to be doing something for HIGH or LOW:

I assume that those are to define if the relay is tripped by a HIGH or LOW signal on this Arduino pin. as they are set they seem to indicate a HIGH will trigger the relay. You might want to have Pull down resistors on your Arduino command pins to force a state when the arduino is booting or not powered.


i hope this is okay now
i cant trigger the relay

assuming RED is 5V and black is GND and Yellow is on pin 10 (hard to see anything on your pictures. A drawing is better) and your arduino is powered through USB

if you run this code:

const byte yellowCablePin = 10;

void setup() {
  pinMode(yellowCablePin, OUTPUT);
  digitalWrite(yellowCablePin, LOW);

void loop() {
  digitalWrite(yellowCablePin, HIGH);
  digitalWrite(yellowCablePin, LOW);

do you hear a click every 2s ?

The Relay is not clicking

the pictures don't help. No need for that

Verify the quality of your cables (try with other ones).

try changing the header for Q1 and put it between LOW and COM

If nothing works then It's possible that your module is defective

have you tighted the screws on your relay board with a screwdriver? The yellow cable looks very loose.

have you connected the yellow cable to PIN 9 or Pin 10?
On the picture it looks like 9.
Modify the sketch from J-M-L to use 9 and report back what's happening.

The screw on the yellow cable is tight sir. and for the pins i tried what youve said PIN 9 and PIN 10 but still it doesn't work.

set the jumper s1 to LOW - COM
disconnect the yellow cable from the Arduino
the PWR LED on the relay module must be on - check it.
now connect the pin of the yellow cable with DC-
does the LED of the output react?
does the relay of the output react?

i tried already this one but still the of the relay doesn't react at all,

send it back for a refund...

I see a 'PWR' LED on that red relay board there.
Does that turn on (light up)?
PE - Answering my own question, it looks like it's on (Green) in Reply#11

the PWR led is turning on when its connected to 5V arduino but LED1 on relay 1 is not Blinking or anything

Maybe you have a 100Ω resistor?
Connect one end of the resistor to "IN2" and touch the other to +5. Any clicks?
With it still connected to "IN2", touch the other to GND. Any clicks?

Still no clicks :<

10Ω ?
I'm reluctant to suggest "0Ω" (a jumper) -- not knowing the specifics.