Control a Fog Machine - Electronics

I am having some trouble trying to figure out how to control a fog machine with an arduino and need some advice. I have a fogger with a mains cable and a remote that attaches via a female three pin kettle lead.

The remote uses two off the wires in the kettle lead (presumably + and -) and attaches them to a small PCB with a switch and two LED's.

When the fogger is plugged in one LED lights, when the fogger has heated up the other led's lights. Pressing the button dispenses smoke.

Unfortunately I cannot (well don't want to) remove the PCB and look at the front as the switch (attached to the case) is soldered and glued onto it, but from looking at the back and guessing the components I have drawn up the (poor) diagram below.

I would like to be able to do three things with the arduino, detect when the power is on, detect when the fogger is ready to fog and be able to trigger the fog. Preferably I would like to avoid using the current remote at all.

My research so far has involved relays as I assume the remote runs at 240v and other ways of controlling equipment, though I have no idea how to "read" when the fog is ready or to save teh remote (best way I have found so far is to connect a relay across the switch so you can trip it with an arduino so to speak!

So in summary:

What do you think?
How would I go about doing this?
What do I need?
What further info could I provide?
Where would you go next?

If you can buy a second remote you could "hack" the buttons of the remote.

Do you have a type number?
Link to specifications?

The fogger is a Prosound 800 - Only info I can find is the manual http://www.maplin.co.uk/media/pdfs/N89GB%20Manual.PDF

The remote is a LC-2X also found in - http://www.maplin.co.uk/media/pdfs/N89GB%20Manual.PDF

Appreciate those aren't very useful as it's just an instruction manual, I can't find any spec on the remote online

Poor photo of the PCB

Poor photo of the remote

Just looked inside the fogger to see where the two pins (that go into the remote) come from.

One of them goes from the remote via a fuse to the wall.

The other goes straight to the pump and to what appears to be another small PCB with three connections, two of these are to (what I guess is) a thermister in the heating chamber.

So somehow the PCB changes the connection to the remote so that the ready light glows when the system is heated up.

I guess (because the ready led has a resister between it and the circuit) that it increases the current to allow it to flow through the resister? Again my knowledge in this area becomes very limited.

Thought about a solid state relay?

With the remote disconnected from the fogger, use a multimeter to measure the value of the components you think are resistors. Measure them both ways round in case they are actually diodes. Also, with the multimeter on the diode setting, measure the LEDs to determine which connectios is the cathode and which the anode.

It would be helpful to know what the voltage across the remote switch is when the unit is live (with and without the fog ready) and whether it is AC or DC, however as it sounds as though one side it at 240v I can't recommend measuring that unless you have a good quality multimeter with well-insulated probes and you really know what you are doing.

As far as I can tell from my very simular, yet in the US and running off 120v unit. the remote itself needs to be plugged into the PCB to complete the whole circuit. as in, no remote, the thing wont turn on at all.. so don't loose it :wink:
at the very least get a second remote, one you can play with, and the other as a back up in case all that fun you had playing with the other one "lets out the magic smoke"

in any case, yes, the unit is using some sort of a thermal resister to determine when the unit is up to the proper temperature to operate/ it could simply be some kind of bi-metal switch that does the work, but in case, this is just a on/off, Binary if you will signal. That closes the circuit that allows the pump switch on the remote to operate.

so... just looking at the remotes PCB I would say that is the control voltage, and that would go live when the unit is ready to go. use that voltage to operate a Relay to give you your input signal to the Arduino that the unit is ready to be used.

the two blobs in the center? that appears to be the switch that controls the fog juice pump. use an out put from the Arduino to operate a relay in place of that switch.

I hope that helps and makes sense. what are you trying to do with the board and fog machine? May I presume a motion sensor or the like to trigger the fog, and the interrupt to determine when its ready to go?