Difference between a resistor and voltage divider in these two examples

[Youkai]

I was watching some Youtube videos about DFPlayer Mini modules with Arduino and came across these two examples. The data pin of that module needs less than 5v to operate properly. One uses a resistor to accomplish this and the other uses a voltage divider. Links are timestamped to the appropriate point in the video.

• Resistor example: https://youtu.be/UodfePdNfg8?t=105
• Voltage divider example: https://youtu.be/P42ICrgAtS4?t=41

What if any is the difference in these two approaches? Is one better than the other?

[ataradov]

Series resistor limits the current that  protection diodes inside the module will have to handle.

The divider is just that - a divider.

The divider is generally better. A proper level shifter is even better.

[gbaddeley]

If the load current varies, a divider will provide better regulation. If the load current is constant (within a few %), the series resistor is just as good as a divider, and has fewer parts, with less heat dissipation.

[Youkai]

Is it safe to assume that the current supplied by an Arduino (or clone) pin is constant and the series resistor is fine here?

[ataradov]

It is not about supplied current. It is about consumed current.

And the calculation for the series resistor value is defined by the current handling capability of the protection diodes.

Generally go with the divider, it is much safer way to operate those devices.