supply a mega2560 via cut usb

Hello community,

i want to run my arduino mega 2560 to read 6 analog sensor signals. The sensor's supply voltage is 5v dc. Is it possible to run my mega 2560 with a 230vac to 5vdc converter? Would it be possible to cut an usb cable and just use the two supply wires to link the converter to the arduinos usb supply? Did anyone try this and/or knows a better solution?

Greetz falu

Yes.. to both. ..but why cut wires? Deactivate the comm-port if you dont want it to be used

The external 5V-supply must be connected to 5V-pin onboard or through the USB-connector to avoid the regulators voltage-drop

There is no regulator drop in using the 5V pin on the Arduino. That is only an issue when supplying 5V to the Vin pin.

Cutting a USB cable is never a good idea.

Thank you for your fast replies. So it is actually possible to supply the mega by connecting the supply to the 5v pin on the board? Correct me if i didnt understand that properly but i thought that this pin is a 5v out pin.

By powering the arduino on the 5V pin, your bypassing the electronics that make the 5V normally on the board, but thats not a real issue.

The only thing is that your 5V needs to be exactly 5V, without ripple or surges or you might damage your board.

Do i bypass the electronics even if i use the usb port on the arduino? If not i will just connect the two supply wires to my ac/dc converter and plug the usb in my arduino. I got one here with output 5v max. 2500mA.

Only difference by USB feed vs 5V direct is that the USB has a 500mA fuse.

falu:
i thought that this pin is a 5v out pin.

It is simply connected to the power supply rail, there is no concept of input and output. I power my Arduinos off a 5V regulated supply through the power supply pin all the time.

knut_ny:
Only difference by USB feed vs 5V direct is that the USB has a 500mA fuse.

That fuse is very slow and offers little short term protection, its main function is to protect the USB supply of your computer.