I was just thinking about this the other day. It's not feasible on a V2 out of the box without getting an E3 V3 with the hotend fan port. Another option is to hook up a relay and utilize the pi's gpio pins to trigger the relay. However, a Raspberry Pi, Octoprint, and some form of gpio plugin are required. You can configure it to fire when the printer begins to heat up or when a specific gcode command is issued. I updated my hotend fan with a 4010 noctua, so it's already perfectly silent. It makes no difference to me.