Relay board is activated On both HIGH and LOW signal

Projects General Guidance
1

i have this 2 channel relay board and want to controll with arduino , but as soon i connect IN1 or IN2 with any pin it will activate relay, so it activate on both cases wether the pin is LOW or HIGH,

Example:
i connect relay IN pin with PIN 2 in arduino
if i run digitalWrite(2,LOW) or digitalWrite(2,HIGH); relay is active(ON), if i remove wire from pin2 relay is off.

2

Code and wiring diagram please

3

and connect the GNDs!

1 Like
4

on 5v board version:
GND is connected to Arduino GND and 5v to arduino 5v

on 12v version, GND to arduino GND and power supply gnd and 12v to power supply

5

This happens with a 5 volt version and a 12 volt version?

What happens if you just connect the input on the relay boad to Vcc, then to GND, then back?

No Arduino involved.

a7

6

Can you give a link to the data sheet? English preferred, circuit diagram may be sufficient.

Setting jumpers required?

7

Did you set the pin to output mode? Again, please post your code and wiring diagram.

pinMode(2, OUTPUT);
8

after runing some tests i see that if i connect IN with 12v it will not triger, or else with triger relay on.

but i have other 12v relay that works on 12 v but they triger with 5v logic , how i need to search the relay so i can buy like that

9

That'll happen with the 12V version ...

image
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... unless configured properly with separate 12V supply for the relay board.

Should also configure it to use the opto isolators.

10

but how this borad works well:
its 12v and i can triger relay with 5v

aa
aa2000×1500 328 KB

11

See the beige jumper on top of the board? A description is required for proper jumper setting.

12

How those board are called , how can i search it if i need to buy .

So its 12v but can be activated with 5v

13

The square chip by the jumper is an opto isolator with an led and photo transistor. The led in it can be triggered by 5v and the photo transistor side turns on and passes the 12v through the primary side of the relay.

14

If you don't have a multimeter, it's time to get one... A cheap one is fine...

You have 3 conditions -
Unconnected
Connected and high
Connected and low.

If you measure the voltage at the relay board's input under the 3 conditions and that will probably give you a clue and help you solve the problem.

Or, an LED (with the usual series resistor) may also be helpful. You can make sure the LED goes on & off, and maybe there will be different brightness levels.

15

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