5v Pro Mini + 3.3v ENC28J60 Ethernet Shield - OR - 3.3v Pro Mini + 5v Relay

Hello, firstly, although my account has just been created, I have actually been roaming around the forums for some time now.
I am currently making a circuit that involves these three products:

  • Arduino Pro Mini
  • ENC28J60 Ethernet Shield
  • 5v Relay Shield

Although I do have a fair understanding and experience with electronics, I am not confident when it comes to creating a conclusion for a method used in a project. I am currently in a predicament that involves the two, 3.3v and 5v, outputs and would appreciate some advice.

As I was trying to create a quick price/materials list I listed a 5v Pro Mini, an ENC28J60 and the relay shield. What I forgot to look into was the operating voltage of the Ethernet shield. After making the list I then proceeded to look into each item properly and found that the Ethernet shield requires a 3.3v input; the Pro Mini does not provide this.

After this I decided to look for the 3.3v 8mhz Pro Mini which, in theory should connect to the Ethernet shield. This then lead to the issue of not being able to drive the 5 volt relay on the relay shield found here:

After following the PCB I had the idea of providing an external 5 volts to the "VCC" and one of the "GND" connections, and providing the 3.3 volts from an output pin of the Pro Mini. Would this solution work or would there still be issues? Please check the link and see if this seems as though the external output would not interfere with the Pro Mini.

Also, if anyone has any other ideas as to how I could connect all three products together without paying much extra, that would also be appreciated.

Thank you for anyone who reads this and thank you in advance to anyone who replies.

I will leave the other matters to someone else as I am not familiar with the Ethernet shield.

The relay module requires 5V as supply, but it does not require 5v to trip it, 3.3 volts should do just fine; there will be no need to convert logic levels.

Awesome! Just as I thought. Thanks for clearing this up, at least if it comes to it, it wont be an issue of powering the relay.