Here is a way to monitor your appliances to tell if they are on or off via an X-10 housecode signal. Uses include washer/dryer monitor to tell when they turned off.
The sensor is a CR Magnetics current transformer part number "Model 19" which can be found here
The Power Flash module is made by X-10 and is available here
Heavy duty extension cord (capable of supplying 20 amp loads) or material to make your own extension cord using male and female 120 VAC adapters and 12 awg wire.
Short piece of 12 awg wire.
This current sensor is made to monitor AC Current and light an LED if the current exceeds two amps. It senses the current going through the appliance's hot wire which is run through its center hole (note to leave the insulation on the wire as the current will still be sensed).
Instead of using this sensor's output to light an LED, you can instead hook the wire outputs of the sensor directly to an X-10 Power Flash unit (with input set to "A" and mode set to "3").
First modify a heavy duty extension cord so the "hot" wire is exposed. If you don't want to use an extension cord, then make your own short extension cord using male and female plug receptacles and 12 AWG wire. Be sure to wire the hot, neutral, and ground wires in the correct order.
You will then run a short 12 awg wire thru this current sensor and connected it in series with the exposed hot wire from the extension cord (see photo below). You could use wire nuts or splices to attach the wire. Be sure cover any exposed wires with electrical tape.
For this test I then connected the extension cord and power flash into 120V AC outlets and attached a heat gun to the female end of the heavy duty extension cord (to act as a test appliance).
I monitored an X-10 log via Homeseer. Whenever I powered the heat gun on the power flash would send out its house code plus ON. Whenever the heat gun was turned off the power flash would send out its house code plus OFF. Note that the heat gun drew seven amps so it was well above the threshold of this sensor's two amp trip point.
If you needed a lower trip point you could "loop" the wire through the sensor (so it passes through the center two times). This would lower the trip point to one amp.
I initially wanted this sensor to trip a relay to give contact closures so a "game port" or my SECU16I/Ocelot could detect it, but haven't had time to test this yet. The voltage supplied by the sensor is AC though and small and I doubt it has much current drive capabillity so selection of a "high resistance, low voltage" relay coil is essential.
One other nice thing about the heavy duty extension cord modification shown is that it makes current measurement via a multimeter really easy (of course tape the open wires during operation to avoid shock and shorts). This measurement would be needed if you were not sure that the appliance you wanted to monitor drew over the two amp trip point.
Here is a little update on monitoring currents for a washer and dryer.
I have a mid-size Maytag washer and gas dryer and I measured some currents while they were running. Both units are 120 VAC powered.
I used a Fluke Multimeter and a "split" hot wire connection from a heavy duty extension cord. (See photo for setup).
The dryer pulled a little over three amps while in the drying mode (well more than the trippoint for the current sensor).
The washer on the other hand would pull only 0.1 amps while filling with water (because only a solenoid valve is on during this time), but would then pull around six amps during the other cycles.
So if this method of current monitoring would be used for monitoring this washer, a timer or sequence script would have to be incorporated, since the trip point of the current sensor is two amps (plus you would have to do to many multiple wraps with the hot lead to get down to this trip point).
Because of this problem I posted another "How-To" for monitoring the washer cycle.
Edited by BraveSirRobbin, 08 June 2006 - 06:55 PM.