I want my Raspberry Pi B+ to periodically check if my Raspberry Pi 3 is still running (not frozen). If it is frozen, I wan't my B+ to hard reset my Pi3 by pulling the power, then giving it power again after a few seconds.
I have bought a 3.3V relay of ebay (view it here) and plan to use it as a switch for the power line of a USB cable.
I have tested the relay directly connected to GPIO pin 18, and GPIO ground. The relay works correctly like this.
My question is: Should I (or do I need) to use a current limiting resistor? Is there any chance of bad stuff happening if I continue to directly connect it to GPIO 18 and ground?