Problem with ethernet+sd card shield and relays

Using Arduino Programming Questions
1

I have one strange problem ,I write a code to drive two relays ,one if tmp. higher and one if temperature lower... and thats work fine ,a use dallas sensor... and I add ethernet shield with sd card slot to mu arduino uno ... Than I edit my code to make logs to sd card.... I try code and everything works fine, arduino write logs. but when I disconnect pc from arduino and use power supply both relays start to blink together... and I connect computer again than everything work fine ... than I disconnect Ethernet shield and relays work fine...
relays use 5,6 digital pins ..... one wire use pin 9 ....

maybe someone have some problem :confused:

2

but when I disconnect pc from arduino and use external power supply both relays start to blink together

The software doesn't know that you are using a USB cable to supply power or an inadequate wall wart. So, incorrectly posting code was not necessary. Some details about your "external power supply" are.

3

Dc Power supply 12v ,1Amp... when I use same supply without ethernet shield relay work fine .. :fearful:

4

I find a problem,it was voltage regulator on arduino .... overheating :grin:

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