Arduino is reconnecting to blynk in every 7 seconds while powering from 12v adapter

I have an arduino mega and w5100 Ethernet shield. Everything works fine if arduino is connected to my laptop but when i connect it via ordinary power supply arduino keeps going offline and connecting again to blynk again and again in every 7 seconds.

To solve this problem I simply powered arduino via usb not from laptop(as i can’t keep my lappy turned on 24*7) but with a 5v usb adapter and it works fine. But again when my arduino restarts (due to electricity outage) i have to press reset button on arduino to again make it working. I’m new to all this so guys help solve my problems.

Power issues are not really a Blynk specific issue.

If it keeps resetting on external power, then the external power source is the issue… not enough current perhaps?

As you have seemed to already have done, simply use a 5v USB battery power bank or 5v USB AC adapter with at least 1amp (valid 1amp, not Chinese rated) supply… if that doesn’t work, then try another… repeat ad nauseum until you find one that works.

Search this forum for other topics on Ethernet and Connection Management options, and study/test them… they might help.

It does sound like a problem with the 12v adaptor you’re using - maybe it’s cutting-out then re-connecting due to an internal problem or an overload.

It’s also possible that there’s an issue with the Arduino’s onboard voltage regulator, as this isn’t used when powering the Arduino via USB, but it is used when powering via the jack.
I’ve destroyed the regulator on an Arduino in the past and could only power it via USB. If you’re handy with a soldering iron, and you have a steady hand and a good magnifier, it’s a simple task to replace it. You can buy them on eBay for peanuts.

You might also want to read this…

The other thing to consider is the idea of changing from the Arduino and Ethernet shield combination and using an ESP8266 device such as a Wemos D1 Mini instead. This would use onboard Wi-Fi instead of the Ethernet shield and can be programmed via the Arduino IDE.


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I have two 12v power supplies one is .5a and another one is 1.5a And It’s not working properly with both of them. I wanted to know if it is okay to power arduino with USB adapter or there are some risk factors included.

Then like @PeteKnight said, it sounds like the onboard regulator is failing, and/or just having issues providing enough current for both the Arduino and the Ethernet Shield.

If you have access to a 5v regulator, then you could make up your own “external” regulator circuit and feed that 5v into the Arduino, via the 5v pin.

No problem at all… that’s how it gets power from the PC and how you can use 5v power banks or 5v USB AC adapters… I still recommend a minimum of 1 amp supply.