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Topic: [solved] relay problem (Read 625 times) previous topic - next topic


Jul 01, 2014, 02:00 pm Last Edit: Jul 02, 2014, 10:56 am by NielsVR Reason: 1
I am recently having some problems with a rely module of my arduino yun.

I was testing the example "blink" of the example library where the led (pin 13) turns of and on and this program works fine.
When i attached the relay (see attachement) the program turns the relay on and off during a minute. After a minute, the led of pin 13 starts flickering for 10 seconds and then the arduino crashed. When the arduino reboots, the process starts again (works for a minute and crashes). When i unplug the relay, the arduino works fine.

I have nothing attached to the relay. Any suggestions?

UPDATE: I figured it out. Turns out that my 5V supply was not stable enough. I replaced the supply with a newer universal phone charger and everything works now. Thanks everybody for the input!


You are definitely not using the "Blink" sketch, because you did not connect pin 13!
For a simple test, just connect Vcc, GND and pin 13 of the Arduino to the relay board and use the original Blink sketch. If that fails, then you are probably overloading the Arduino's 5V regulator which is feeding the 5V pin.
If the test is OK you have a problem with your sketch.


Do you have the USB ext power selector in the USB position?
No technical PMs.
The last thing you did is where you should start looking.


quick, turn off the power.

now, get the data sheet for the relay.  you might find that the power requirement for the relay will be more than you can put through your arduino.

the relay is designed to have a separate power supply.

also, most have opto isolators.   on the low relay count boards, they supply power to the opto. on the high relay count boards, they pull to ground (as you show).

what you do not show is the power source for the relays.

get that data sheet, if you want help, post a link to it.   without knowing if you need to supply 5v or pull down the 5v, we are only guessing.


It looks like a relay board which includes opto's or transistors to do the switching.


Hi, i have same problem, and resolved unused the pin 13... when arduino runs the led blink automaticly, then turns on.. i think arduino uses this pin 13 and led for show start, i dont know. see mi topic, is in spanish, sorry bad english. used pin 13 give me problems for start arduino to, never start.


used pin 13 give me problems for start arduino whit external 9v., never start and relay go crazy

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