I got a few of the current sensors mentioned in this thread to monitor if certain devices are powered on. The first one I used on the dryer. I opened up the small access panel where the plug is terminated (as mentioned here), disconnected a leg, peeled it apart from the rest of the power cable and inserted it through the current sensor. I turned on the dryer to test it out (it was on the 'air dry' setting), but the sensor didn't activate because the heater wasn't on. If I switched it to a heated cycle, the sensor triggered. So I had to move the current sensor to the other leg, which is active whenever the dryer is on. After putting everything back together, I attached the sensor output to a DS10A so that it can send the dryer's power status wirelessly. Now, whenever the dryer turns on, the laundry room exhaust fan turns on and when the dryer is done, the laundry fan turns off 2 minutes later.