It is ok and reliable to use 5v relay with arduino due 3.3v without logic level shifter ?, what do you think ?

 

Have the Duo drive a transistor and run the relay off 5V.
The Duo will not drive the relay directly as it does not have the current capability on its port pins.
And it is always a good practice to have some isolation between the controller and the load.
A 5V relay may work on 3.3V, but for reliability, use what the relay is rated for.

 

It is ok and reliable to use 5v relay with arduino due 3.3v without logic level shifter ?

No.

 

It is ok and reliable to use 5v relay with arduino due 3.3v without logic level shifter ?, what do you think ?

A 5V relay would probably pull in at 3.3V, but I don't know of any relays that will work at the level of current an arduino could supply. Use a transistor to drive the relay as @dendad said.
And don't forget the diode across the coil.

 

A 5V relay would probably pull in at 3.3V, but I don't know of any relays that will work at the level of current an arduino could supply. Use a transistor to drive the relay as @dendad said.
And don't forget the diode across the coil.

Is using logic level shifter is more reliable ?, yes... relay will triggered with 3.3v even 2.8v but it's labeled for 5v use

 

Is using logic level shifter is more reliable ?, yes... relay will triggered with 3.3v even 2.8v but it's labeled for 5v use

If you know the voltage is OK, that’s half of it. The current is the other half. Can the Arduino deal with the current the relay demands?

A level shifter isn’t particularly important but something that can handle the current is. A transistor is a simple and standard solution to this.

 

It is ok and reliable to use 5v relay with arduino due 3.3v without logic level shifter ?, what do you think ?

Use this, it is nearly transparent to relay coil voltage.


If you try like this, your MCU will fry.

 

Agree, normally use a transistor to drive the relay coil would do. I'm not too sure if things like 2N2222 is adequate to drive it.
Otherwise, you may like to use a TIP110
https://www.onsemi.com/products/discrete-power-modules/darlington-transistors/tip110
transistors are 'easier' to drive as unlike mosfets, BJT has very low turn on voltages, but BJT do have rather large saturation voltages.