When I got back from flying today, I've finally finished off the units for Shaun and Ron. Sorry for the delay guys, they'll be posted out on Monday.
I made a small change to the mount so that a bent pin can be pushed through a hole and there is a 'hook' or 'latch' to clip the pin behind to stop it falling out. I updated the image of that mount, plus the stl files and openScad files in the post on the first page where I originally put them.
click picture for bigger view
You can see the new little pin in the photo. This is the one that I'm sending to Ron, and Shaun's is pretty much identical. The blue wire is the rudder input from your receiver, the violet wire the elevator input, and the grey wire the auxiliary input that allows you to switch the pulsing off from your transmitter and allows you to control the percentage of time that the motor is powered.
I've been thinking of modifying the sketch so that if the 'aux' wire isn't connected to the receiver then the unit will automatically default to some sensible preset power level. This will allow the unit to be used with simpler transmitters (maybe vintage ones) that don't have an 'aux' channel that can be operated by a switch.
The red and black wires are for connection to the battery - red is the positive, of course. The unit seems to work fine from 5V and doesn't draw much current so you could perhaps connect these to the receiver and use the normal 5V receiver supply from the ESC BEC - but I connected mine to the same two cell battery that powers the plane. It might be okay on three cells but the Arduino input is only officially specified up to 12V and fully charged three cell is 12.6V.
As there are only three input 'signal' wires from the receiver to the Arduino, you must ensure that the Arduino ground (black wire mentioned above) is connected to the same ground level as your receiver. If it's an electric plane with the receiver powered by the ESC BEC in the usual way then this will automatically be the case.
Near the top of the photo you can see the clamp screw that attaches the coupler to the drive wire that goes to the rudder (and maybe elevator) on your plane. You just slide a piece of thin (16 or 20 swg gauge or similar) straight piano wire into the hole and tighten up the screw to secure it. It's useful if you have access to the screw somehow on your assembled plane as this allows you to adjust the centre position of the 'waggling' without having to bend the wire. It's also a good idea to put one or two short lengths of plastic tube supports for the drive wire part way along its length (mounting all the supports with light fixings to the fuselage so they're in a straight line) - that stops the drive wire from whipping around inside the fuselage when it's oscillating.
Private message your address and I'll send you a free one, ready to go. I'm making a batch of three right now as Shaun wants one for his museum / collection, and I'm going to give the last one to Mike (Ralkbirdy) to force him to build something for it. 
