Homebrew PCBs

Thanks, Harvey, for the detailed description - Very interesting 
setup. One of these days I'll work on something similar, though I 
rarely drill a lot of holes. I use almost exclusively smt and usually 
make single sided pcbs using zero ohm resistors as jumpers.

Mark


At 06:50 PM 8/15/2014, you wrote:
>On Fri, 15 Aug 2014 12:52:18 -0400, you wrote:
>
> >Hello Harvey,
> >
> >I'm interested in getting more information on your drilling setup,
> >mostly the optical stuff - camera, software, monitor. What supplies
> >the reticule image for the crosshairs?
>
>OK, in short.  The optical stuff is a 12 volt/24vac camera with almost
>any lens that works well.  You want to move it out away from the CCD
>so that you have the equivalent of a closeup extender.
>
>That goes to a standard color monitor.  This is an LCD monitor that I
>found (runs off 12 volts DC), and has an overlay with a graticule on
>it.  I've been tempted to make it more complicated by adding a
>crosshair generator, but that'd be another PC board and some video
>work.  The graticule is easier.  Just make the pattern on a
>transparency and put it over the monitor itself.  Almost any old TV
>would work.
>
>The software is custom, and is a simple Z axis setup.  There are two
>pushbuttons (green/red) and a rotary encoder with a push switch
>(Electronics goldmine sold them).  There's an end travel (and top
>travel) led sensor.
>
>Boot up, the display says to push green to home.  That homes the drill
>and runs it up to the rest position.  pushing the footswitch (or the
>green pushbutton) starts a drill cycle, three speeds possible, up to
>the drill top position.  At that point the drill retreats back to the
>rest position and turns off the Proxxon tool (solid state relay, works
>better with the 12 volt model and transformer).
>
>Pushing the red button puts the drill at the top position, which is
>where I can change the bit from the top.
>
>Pushing in the rotary switch/encoder put it into an adjust mode, where
>I can set the rest and top positions (stored in the processor's
>eprom).
>
>Basically, the software is not all that complicated, but does rely on
>an infrastructure of display drivers (it's a smart display that I
>built), a modified keyboard driver package, and a few other bits and
>pieces.
>
>Physically, the camera is mounted on a PACE hot air station stand (I
>managed to find two for not so much money), which gives me an
>overarching arm for the camera.  I can move it up and down to focus
>the camera and move it out of the way for drill change.  I suppose
>another enhancement would be to put a stepper drive on that.
>
>You will have to align the camera center point to the tip of the
>drill.  In my case, the adjustment is entirely mechanical, with the
>camera swinging left/right on the mounting screw, but tilted (spring
>used on screw) forwards/backwards as needed.  That's a trifle awkward,
>and the electronic crosshair generator would be better.  That would
>require a small CPLD, a sync separator, a synchronized pixel clock,
>and some counters.  Ideally, the graticule has ticks on both axis
>lines, since that helps align the center of large holes.
>
>The smallest hole I drill is 0.021 for a via, and I estimate that I
>can repeat that hole to within 0.002 inches roughly.  The size of that
>hole on the monitor is the critical part.
>
>You'll want to backlight the board.  Red light may be most useful, but
>I haven't experimented with that yet.
>
>Hope that this helps.
>
>Harvey
>
>
> >
> >Thanks.
> >
> >Mark
>
>
>
>------------------------------------
>Posted by: Harvey White <madyn@...>
>------------------------------------
>
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