Further to Dave letting the cat out of the bag, for those of you who are curious here are a few more details of the new gun controller. The picture shows a prototype unit such as Dave is currently evaluating. The production board will only differ in that it will have a 3.5mm stero jack socket for use with an external amplifier for those wanting an attention grabbing 'bang' when their gun fires! Otherwise the unit features the very same 3W sound module as reviewed by 'unbuiltnautilus' at the start of this thread and whose output volume was judged to be 'excellent'.
In contrast to my servo based gun controller
http://www.forge-electronics.co.uk/index.php/boats/servo-controllerthis unit uses a stepper motor to rotate the gun so that rotation in excess of 180 degrees can be achieved - 270 degress is typically required for battleships. With no rotation constraints the stepper motor can achieve any angular rotation including continuous. Also with 4096 steps per rev the rotation is extremely smooth.
Again in constrast to my earlier servo based unit the speed of rotation is now proportional to joystick displacement. A potentiometer also allows users to set the maximum speed of rotation to suit their particular installation.
A further RX channel is available so the gun may be fired at will and the aforementioned sound unit is used to create the 'bang' (users can substitute their own gun sounds on the microSD card). In the absence of a 'fire' channel the unit can be configured to automatically fire at the limits of rotation or (once) when the gun comes to a halt after movement. Provision has been made to drive a white LED to give a muzzle flash (most probably a below deck LED will be used to feed an optical fibre threaded up the gun barrel). If a further RX channel is available there is provision to drive a servo to elevate the gun and another servo output automatically provides a recoil action for those clever enough to engineer this.
In the absence of an elevation channel the gun will automatically elevate and depress as it rotates, the minimum and maximum elevations being user configurable.
The sound module also gives verbal guidance during the setup procedures.
For use at exhibitions it is possible to put the unit into a demonstration mode where it sweeps from side to side automatically elevating and depressing as it does so. For user convenience this mode is triggered from the transmitter by holding the gun at its extreme limit of rotation (with the joystick still pressed) for ten seconds. Further jogs of the joystick select three different angular rotations at three different speeds. A press the other way cancels demo mode. During this mode the gun may be fired at will and though 'auto end stop' firing is possible I think it would quickly get very irritating!
Multiple guns can be daisy chained from the stepper motor drive output to turn in synchronism and an expansion board is available to feed 4 guns maximum. The expansion board has provision to reverse the direction of rotation of any of the guns so those at the stern can turn to face in the same direction at those at the bows.
The unit takes a 7 to 12v supply to operate - no power is taken from the boat's 5v receiver supply. Why? well traversing, elevating, firing and recoiling all at the same time would overwhelm the BEC in most ESCs so a separate 3A UBEC is fitted. Correction, the relay coil *IS* fed from the 5v RX supply and its relay contacts connect the 7-12v to the unit - I've fitted this as many ESCs have a dinky on/off switch that shuts down the BEC but DOESN'T turn off the main 7-12v battery supply. I liken this to leaving a loaded, cocked revolver in your desk drawer -there's no reason for it to go off but you wouldn't do it! Thus the relay is fitted to prevent the gun controller remaining powered with the ESC switched off for those who fail to disconnect their battery after use.
Only available following satisfactory conclusion of several user evaluations, price not yet determined but you can probably manage with one kidney anyway!