This may be a silly question but can someone please let me know how to power a Arduino Mega 2560 without the USB cable. I am able to upload the code and run my 5V hitec 311 servo just fine with the USB cable connected. However when I connect the power source (12V adapter) to the Arduino and unplug the USB, the Arduino is no longer lighted up and nothing happens with the servo. Thanks!
Note: I used a voltage meter to measure voltage between ground and Vin with the 12V adapter connected to the Arduino Mega and get no reading. I double checked the adapter and it is good, supplying 12V. Is the Arduino fried? Any way I can confirm it?
What happens if you unplug the servo? You really shouldn't power the servo from the Arduino, it needs more current than is safely available. Look out for DuaneB's posts. He has some excellent information on servo powering.
I removed the servo and just measured the voltage between Vin and Ground - still nothing.
I tried using a 7805 voltage regulator (12V to 5v) with capacitors on both sides but that resulted in the servo just making noise and not doing anything. When you say I shouldn't power the servo from the Arduino, do you mean not power using the USB or not even power from the DC power jack (12V 6Amp)?
This may be a silly remark but .. if you attach the 12v source between Vin and Ground and get no voltage, it would be the voltage-source that is failing.
