5V switch relay

Hello, I am currently working on an project where I would like to switch on a relay when this LED on another device usually turns on. I removed the LED from the device and attached some leads. The only problem is that my relays require around 12v and the LED only receives 5v. So I was just wondering how I can use the 5v that is meant to power the LED to switch on a 12v relay. Assuming that there is at least a separate 12 v source at your disposal. Thanks!

If the relay is 12V DC, you could just use a transistor to control the relay from the 5V. What coil current does the relay require?