10Bulls' Christmas Tail

II. The Solution...

OK, the ‘device’ is starting to take shape.

First I cut off a length of the 100mm diameter acrylic ‘bubble’ tube.  Having no hard and fast data to hand on the velocity of a startled mouse, I decided about a foot of tube should suffice.   At least I hope so or this escapade could end rather messily for poor old Noel (rhymes with vole).

The original end cap will do nicely for blocking off the rear retreat which just leaves the ‘clever bits’ to make for the entrance.  This is where the CNC part comes in.  The door, in principle, is rather like Xairflyer's aircraft vents, with a fixed outer plate containing an entrance hole and a rotating inner disc with a matching hole.  The inner disc will be connected to a stepper motor and the entrance holes aligned.

The discs were designed, and in a pleasingly short time I had some gcode to hurl at my machine which had been feeling somewhat neglected over the past couple of months.  The acrylic was cut and drilled to a precision I could only dream of several months previous, at a fraction of the time and immeasurably more enjoyable than doing these sorts of things by hand.  CNC is a wonderful thing indeed.

A bait will be placed inside the trap with a hair trigger originally designed for Humpa the Robot (a story for another day), connected to the inputs of a PIC microcontroller board, which is in turn connected to a stepper motor controller.  Both the pic board and motor controller were conceived a number of years previously.  The intention was for them to be general purpose and modular.  They have controlled a variety of gadgets including robots, LCDs and hydroponics controllers; but this is not their tale.  Other than to mention, it was the frustration and monotony of fabricating these utility boards which set me off on my CNC quest in the first place.

Triggering the PIC will rotate the stepper a set number of steps which should, in theory block Noel’s escape and voila: the kids have a new pet for Christmas; Noel gets a reprieve; Hopefully you all get some cheap entertainment; And I get to escape for indeterminately long spells into the garage over the festive season.  Genius!

But Christmas is now just over one day away and there’s still much to do.  Will you all get to feast your mince pies on Noel before the new year or will his goose get cooked?  Stand by for another nail biting instalment of 10bulls' Christmas tail : Best Laid Plans. Coming Soon....