Electronic control for bath fan + light

[miamicanes]

Does anybody make a bathroom fan + light controller that

1) Supports two switch locations (ie, 3-way)

2) Lets you use one switch/button to toggle the on/off state of the bathroom light, and intelligently changes the state of the exhaust fan to follow. For example:

light and fan off: turns on both light and fan

light and fan on: turns off light, begins timed countdown before turning off fan

light on, fan off: turns off light, fan stays off.

light off, fan on or in countdown: turns on light, fan remains on

3) has/supports a second switch that specifically toggles the state of the fan. Thus, if you want to change the state of the fan without affecting the light, you'd flip this switch.


I'm *this close* to building my own using an Atmel microcontroller, a relay board, and wall switches connected to the AVR's I/O pins instead of 110v... but before I burn a week or two when I should *really* be working on making my bathroom usable again, spend around $150, and do something that would probably raise a building inspector's eyebrows or worse, I want to ask whether anyone makes anything remotely resembling a product like this. It seems like something that's painfully obvious, but manufacturers just can't get right (if they even try at all), and as a result everyone ends up either putting the fan and timer on separate switches (which causes the fan to be under-utilized since people are lazy and forget to turn it on), or put them on the same switch and end up leaving the light burning for hours at a time because they didn't want to prematurely turn off the fan, then ended up going to work with both still on.

The closest thing I've found to what I want is the Air King AKDT60, but THAT switch has one fatal flaw: it doesn't work in 3-way configurations... and the bathroom in question has two doors -- one leading to the bedroom, one leading to the hall.

Argh. Does anyone make anything remotely comparable, but 3-way usable? Or is it a case of make it myself, or do without it?

 

[signal15]

Can't you just use some Insteon dimmers, and create different scenes with them?

Check out this thing:

http://www.smarthome.com/2412N/SmartLinc-I...ntroller/p.aspx

It allows you to control your Insteon stuff through an iPhone or iPod, but I believe it also allows one to create different rules which dictate the operation of different devices. Grab this thing and a couple of dimmers. Plus, you can expand the system as needed to the rest of the house.

 

[Rupp]

Sounds like a perfect fit for a UPB, Z-Wave, Insteon and software control package. I use humidity sensors to control my bathroom fans and this has worked out well. The Oregon humidity sensors with the ACRF plugin and HomeSeer all combine to monitor the humidity level and automatically control the fan status.

 

[miamicanes]

> Can't you just use some Insteon dimmers, and create different scenes with them?

Two problems, both dimmer-related:

1. The lights are all compact fluorescents. Dimmers are taboo with 99% of CF lights, and expensive & dysfunctional with the remaining 1%.

2. A/C fans don't like dimmers, either. It makes them hum and burn out sooner. I know, because I had a ceiling fan wired through an X-10 dimmer switch. I never actually ran it at anything less than 100%, and only had it on the X-10 switch so that on those rare nights when it got cold after going to bed I could kill the fan without getting out of bed. The hum drove me nuts, and the fan burned out in 5 or 6 years.

> Sounds like a perfect fit for a UPB, Z-Wave, Insteon and software control package.

Actually, that reminds me... I have an Elk M1G. Is there any straightforward way to use IT as the controller for UPB/Z-Wave/Insteon/X-10 switches & inline relays? I know it can directly control X-10 (and probably Insteon, and poosibly others) with an additional module, but I'm not sure whether it has a sufficiently rich programming language to implement something involving context and state (no 'else' construct and severely limited booleans, from what I remember from the last time I tried being adventurous with it). Alternatively, an Elk i/o board (I think it has 4 inputs and 4 relays) would be a pain to install, but not necessarily out of the question if it would make it more straightforward or significantly cheaper to implement...

 

[signal15]

> Can't you just use some Insteon dimmers, and create different scenes with them?

Two problems, both dimmer-related:

1. The lights are all compact fluorescents. Dimmers are taboo with 99% of CF lights, and expensive & dysfunctional with the remaining 1%.

2. A/C fans don't like dimmers, either. It makes them hum and burn out sooner. I know, because I had a ceiling fan wired through an X-10 dimmer switch. I never actually ran it at anything less than 100%, and only had it on the X-10 switch so that on those rare nights when it got cold after going to bed I could kill the fan without getting out of bed. The hum drove me nuts, and the fan burned out in 5 or 6 years.

> Sounds like a perfect fit for a UPB, Z-Wave, Insteon and software control package.

Actually, that reminds me... I have an Elk M1G. Is there any straightforward way to use IT as the controller for UPB/Z-Wave/Insteon/X-10 switches & inline relays? I know it can directly control X-10 (and probably Insteon, and poosibly others) with an additional module, but I'm not sure whether it has a sufficiently rich programming language to implement something involving context and state (no 'else' construct and severely limited booleans, from what I remember from the last time I tried being adventurous with it). Alternatively, an Elk i/o board (I think it has 4 inputs and 4 relays) would be a pain to install, but not necessarily out of the question if it would make it more straightforward or significantly cheaper to implement...

You could certainly use the M1 relay board. I think that board can switch up to 15 amps per relay or something like that. Better look at the specs but it should be fine for a few lights and a fan. The question is, how do you plan on doing the switches if you go this route? I would probably just get a couple of on/off (not dimmer) insteon switches and the insteon controller for the M1 and then write my automation rules. You wouldn't have to run extra wire that way either.

It's not a ton of money, but it's not cheap either for what you are trying to do. But if you look at is as something that you can use to expand to the rest of your house at some point, you should be able to justify it.

 

[miamicanes]

OK, here's my wiring topology:

M1G in kitchen, RS-485 bus connected to what was originally the house's 6-wire phone cable.

Elk input expander connected to what used to be the living room's phone jack, with all downstairs sensors connected to it. There's a M1KP2 connected to the RS-485 bus here, too. Two of the 6 wires are liberated at this point... I'm using them to carry audio from the M1G to the speaker mounted nearby.

M1KP upstairs in the master bedroom, once again connected to the former phone cable. Those two wires, in conjunction with the +12v furnished by the RS485 bus, are used to connect a window sensor and undercarpet pressure pad to the input expander downstairs. The input furnished by the M1KP in the master bedroom is used to connect that bedroom's window sensors.

The proposed i/o expander would connect to the RS-485 bus about 25-40 feet downstream from the master bedroom's M1KP.

The main thing that worries me a little is cable length. I could double up the wires used for power between downstairs and upstairs by moving the two sensors currently using two wires to the new upstairs i/o board, but there's still the initial 25 feet or so where the whole power supply between the box and first input expander+keypad is carried by a single pair of wires in the old phone cable. It works OK now, but I'm a little worried about pushing my luck and adding another expansion board further downstream.