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[clunker]

I'm new to X10 and there's one thing I've been dying to do:

We have a dryer in one of our bathrooms and when you run the dryer you need to make sure the fan is on, because the bathroom fan is also the exhaust fan for the dryer.  There is a single switch that controls this fan and also the light.

Now, it is very natural when you leave the bathroom, having completed whatever you went in for, to turn the light off.  If the dryer is on, though, this is a very bad thing.  It's also common to start the dryer and then leave the house, go to sleep, etc., and yet in that case the light/fan stays on unnecessarilly.

So, my intention is to install an X10-compatible switch that will transmit on one unit code (to a macro) and have the power triggered on and off from a different unit code.  Then I'll have something to detect when the dryer is running and have that send yet another signal.  I'll probably add a motion sensor to the mix and write some nice macros to make everything work the way I want.

I found a nice light switch, and I purchased an AC clamp meter (w/ detachable clamp - it's perfect and cheap!) to detect current through the dryer's power cord.  Now I just need the right device to send the signal (and figure out how to interface the clamp with it.)  I'm not really familliar with the products.  Anyone got any ideas?  I'd prefer if it wasn't battery-operated.

[-Bill- (of wgjohns.com)]

Interesting idea...

Check out the Powerflash module, it gets a trigger from a low voltage or a contact closure then sends an X10 powerline signal.

Then you just have to figure out how to get an output from your "clamp meter" to trigger it.

[dave w]

clunker

As Bill said adapting the current clamp meter to provide the desired input to the Powerflash is going to be your challenge.

If you have trouble interfacing the current clamp you might try what I did to sense the operation of a 240V well pump. I found a 240V to 12V transformer and wired it across the pump feed after the pressure switch. The low voltage side of the transformer drove a Powerflash module.

220V transformers are under $5 at www.allelectronics.com or www.meci.com.

You would have to wire the transformer primary across the dryer motor. If your dryer motor is 120V just use a 120V to 12V transformer instead of the 240V. The Powerflash will send out an "ON' code with a low voltage AC or DC input, or a relay closure. So you could substitute a 240V coil relay for the transformer if you wanted.

If I understand your proposed solution, a second problem you might have is: nothing will prevent a person from turning off the fan/light switch as they leave the bathroom. So you might want a non dimming wall switch which will send out a status code whenever it has a change in status. I believe you will have to go to www.smarthome.com for that switch, as X10 does not make a "2-way" wall switch. Your macro would then have to turn the bath fan/light back ON if it received a "status OFF" from the switch with the dryer still running.

Good luck, let us know if you manage to use the current clamp method as I too have a clamp, not being used.

[clunker]

The only problem with your solution is that my wife would kill me.  A non-contact solution is the only option for my first project if I ever want to have a second project.

Yeah, I got the switch at smarthome - an Icon On/Off switch which I believe will do the trick - and had the same idea for the macro.  When I add a motion sensor, I'll add a delay after the dryer stops and if the motion sensor hasn't tripped during that delay period, then it will turn the light off.

I opened the clamp up and it's 4 pins are conveniently labeled +5, -5, GND, and Output.  Since I need low DC voltages anyway, I'm thinking of going with a DS10A door/window sensor.  I wish I had a schematic for it, though - I suspect if I knew where to make the connections I wouldn't need to add a relay.  On the bright side, it does seem to operate OK at 5 volts instead of 3 and I suspect the clamp won't complain too much if it's +5 is +7, so I can probably get by with just +5 and +12 volts.

I'll update this thread with any progress.

[vhoang]

Just an idea, not sure if there will be problem since it's in a NC module and will flop very often:

a rudimentary vibration sensor stuck on the side of the dryer and connect it to a powerflash module?

http://www.sensorsandmore.com/?mod=product&cat_id=1&product_id=62

[Oldtimer]

Just an idea, not sure if there will be problem since it's in a NC module and will flop very often:

a rudimentary vibration sensor stuck on the side of the dryer and connect it to a powerflash module?

Actually I think this is a very good idea.  To eliminate the "flopping" why not use a DC wallwart of appropriate voltage for the powerflash and put a VERY large capacitor, with an appropriate bleeder resistor accross it, so that it has to be off for a few seconds (minutes if you want to allow for dryer load checking) before the powerflash senses an open contact.  You'll have to experiment with various values to get it right but the capacitors are available from electronic surplus houses.  Maybe one of the electron heads on this forum can suggest a value range for the capacitor so you only have to buy one.  You can then cobble together the resistance from parts in your scrap box.

[Puck]

I've haven't used a PowerFlash, so not sure what it's triggers are, but following along vhoang's & Oldtimer's suggestions, (and if you don't already know of course):

Time (seconds) = Resistance (Ohms) X Capacitance (Farads)

This is the time for the Cap to charge to 63% or discharge to 37% of the voltage thru the resistor. Depending on how the PowerFlash works, you might need to build a Comparator Circuit.

[Oldtimer]

Now that Puck's formual is available I was all set to post a circuit diagram that connected the vibration sensor to the Powerflash when I realized we have another problem to overcome.  Since the same switch controls both the light and the fan how will the sensing circuit know that the light switch has been turned off so it can turn it back on?

In a way this is similar to the problem I had in one of our bathrooms with the same set up.  I wanted a timer on the fan independent of the light switch.  I had to install a second electrical box above the original one to install the mechanical timer for the fan.

Let's assume you do the same thing but the second box contains an appropriate appliance module or wall switch instead of a mechanical timer.  The wiring would now be that BOTH the light switch and the appliance module/switch be wired to the fan in parallel (not per code!)  I did this for a different application in our last house and it worked perfectly for years.  You just have to be careful to get the polarities the same.

Now whenever anyone comes into the bathroom and turns on the light the fan goes on.  Whenever the dryer goes on the fan will go on per the yet to be published external circuit.  If either goes off while the other is on the fan will still operate.

If this modification is acceptable I'll publish my time delay diagram.  Actually I may anyway since someone else may be interested.

[HA Dave]

I'm new to X10 and there's one thing I've been dying to do:

We have a dryer in one of our bathrooms and when you run the dryer you need to make sure the fan is on.

... install an X10-compatible switch that will transmit on one unit code (to a macro) and have the power triggered on and off from a different unit code.  Then I'll have something to detect when the dryer is running and have that send yet another signal. 

If your using AHP...why not install the (X10) Levitron 220 dryer plug (6298W  or simular model).

Then the wall switch (X10) for the fan.

Then write your macro to turn the fan on when the dryer is on.

Wouldn't that work?

[Oldtimer]

Now that Puck's formula is available I was all set to post a circuit diagram that connected the vibration sensor to the PowerFlash when I realized we have another problem to overcome.  Since the same switch controls both the light and the fan how will the sensing circuit know that the light switch has been turned off so it can turn it back on?

In a way this is similar to the problem I had in one of our bathrooms with the same set up.  I wanted a timer on the fan independent of the light switch.  I had to install a second electrical box above the original one to install the mechanical timer for the fan.

Let's assume you do the same thing but the second box contains an appropriate appliance module or wall switch instead of a mechanical timer.  The wiring would now be that BOTH the light switch and the appliance module/switch be wired to the fan in parallel (not per code!)  I did this for a different application in our last house and it worked perfectly for years.  You just have to be careful to get the polarities the same.

Now whenever anyone comes into the bathroom and turns on the light the fan goes on.  Whenever the dryer goes on the fan will go on per the yet to be published external circuit.  If either goes off while the other is on the fan will still operate.

If this modification is acceptable I'll publish my time delay diagram.  Actually I may anyway since someone else may be interested.

Time (seconds) = Resistance (Ohms) X Capacitance (Farads)

This is the time for the Cap to charge to 63% or discharge to 37% of the voltage thru the resistor[/b]. Depending on how the PowerFlash works, you might need to build a Comparator Circuit.

Using Puck's formula above and the second box per my other post above, this is the circuit I would try first.  This assumes that the PowerFlash (PSC01/PF284) will be set to Mode 3 (6-18 V DC):

Parts List:

• Wall Wart = Probably 12 volts DC or more.
• S = The switch in the vibration sensor. 
  It'll be interesting to see how long this lasts considering that one dryer load produces more vibration than the sensor would normally see in a lifetime in its intended application.  I don't think you'll have trouble however.
• C = Whatever appropriate "super" capacitor you can get surplus. 
  Its rated voltage will have to be the same as your Wall Wart, or, if it's cheap enough get four and hook them up in series parallel to up the voltage rating.
• R1 = Time delay trimming potentiometer.
• R2 = PowerFlash voltage input trimming potentiometer.

NOTE: The combined resistance of R1 as adjusted and R2 is the resistance value to plug into Puck's formula.

You'll need to do a little Googling to find these parts, particularly the capacitor, without spending an arm and a leg, but they are out there.

With the wiring scheme in my other post, above, you may not need a very big capacitor since you only really have to smooth out the momentary ons and offs of the vibration sensor, although I might shoot for 10 to 15 seconds.  Play around with the capacitance/resistance values you find on line and see what you come up with.

The other thing to keep in mind is that the vibration sensor may have a prefered motion sensing direction.  That would control whether you mounted it on the back or side of the dryer. I suspect you'll end up on the side.


[TTA Edit: Added some formatting. ]

[clunker]

Good ideas - I probably will go with a vibration sensor since they are cheaper and easier to interface with.

[gil shultz]

I would check with your local building inspector, this would not meet code in our area.  You are pumping a tremendous amount of moisture and heat into your home.  I am glad I do not have your AC bill.  The best solution would to vent the dryer to the outside. Using the local laundromat for the drying would be a lot cheaper then the AC especially in the summer.  The moisture cycling in your home must mess up the furniture and hard wood floors if you have them.

Gil Shultz

[rms59]

I would check with your local building inspector, this would not meet code in our area.  You are pumping a tremendous amount of moisture and heat into your home.  I am glad I do not have your AC bill.  The best solution would to vent the dryer to the outside. Using the local laundromat for the drying would be a lot cheaper then the AC especially in the summer.  The moisture cycling in your home must mess up the furniture and hard wood floors if you have them.

Gil Shultz

Exactly right. In my town the dryer must be vented to the outdoors with metal flex pipe minimum.... Good luck.

Dick