Category: Photography & Images

The SX230HS camera lives in my pants pocket, where it gets pressed between my leg and anything I lean against. Turns out that the lens turret end cap isn’t quite thick enough to not bend inward against the leaves that cover the lens, which causes them to hang up. The solution boils down to a hideous external lens cap:

It’s built from forget-me-not yellow filament for an obvious reason…

The sheet-metal plate bears against the non-moving rim around the turret. I marked the plate’s diameter with a compass, extracted it from the sheet with left-cutting tin snips, filed off the slivers, rounded the edge, and it snapped right into the recess where a touch of acrylic caulk holds it firmly in place.

A thin plastic cover would be too flexible and a thicker plastic cover would be too thick; this must fit into an already-snug cloth pouch where a few additional millimeters of girth actually matter. My previous camera taught me that pocket fuzz gets into everything, so a pouch isn’t optional.

The interior isn’t too inspiring, but you can see what two layers of plastic look like across the bottom:

The front has the shallow recess that captures the metal plate. Because the front builds against the aluminum build platform, I added a support structure inside the recess:

The solid model gives a better view:

It’s basically a ring with tabs under the recess. The ring OD matches the lens caps’s ID, with a height equal to the recess depth, so only the tabs contact the cap. I removed them by twisting each tab with a needle-nose pliers until the whole thing popped loose:

A bit of scraper and scalpel cleanup and it’s all good. The detail pix show the first trial of the lens cap, which lacks the nice bevel around the front rim.

The camera is smart enough to notice when something blocks the lens: it immediately shuts down and displays a lens failure error message. That’s probably not a Good Thing on a regular basis, but it doesn’t seem to do any harm.

FWIW, my previous pocket camera, a Casio EX-Z850 , sported a recessed and somewhat thicker turret end cap that didn’t have this problem. Mary says she’ll make a case for this camera, too, but until then I’m using a pouch from a dinky VOIP phone that just barely holds the camera.

The OpenSCAD source code:

// Lens cap for Canon SX230HS
// Ed Nisley KE4ZNU - Nov 2011

//-------
//- Extrusion parameters must match reality!
//  Print with +1 shells, 3 solid layers, 0.2 infill

ThreadThick = 0.33;
ThreadWidth = 2.0 * ThreadThick;

HoleFinagle = 0.20;
HoleFudge = 1.00;

function HoleAdjust(Diameter) = HoleFudge*Diameter + HoleFinagle;

Protrusion = 0.1;			// make holes end cleanly

function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);

//-------
// Dimensions

LensDia = 53.0;
LensRad = LensDia/2;
LensLength = 8.0;

PlateThick = IntegerMultiple(0.75,ThreadThick);
PlateDia = 48.0;

Shell = 2*ThreadWidth;
Spacer = 2*ThreadThick;

CapOD = LensDia + 2*Shell;
CapLength = LensLength + Spacer + PlateThick;
CapSides = 48;

CenterHoleDia = 44.0;

BevelWidth = PlateThick;

NumStruts = 16;
SupportStrutLen = (PlateDia - ThreadWidth)/2;		// small gap to cap

//-------

module PolyCyl(Dia,Height,ForceSides=0) {			// based on nophead's polyholes

  Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);

  FixDia = Dia / cos(180/Sides);

  cylinder(r=HoleAdjust(FixDia)/2,h=Height,$fn=Sides);
}

module ShowPegGrid(Space = 10.0,Size = 1.0) {

  Range = floor(50 / Space);

	for (x=[-Range:Range])
	  for (y=[-Range:Range])
		translate([x*Space,y*Space,Size/2])
		  %cube(Size,center=true);

}

//-------

ShowPegGrid();

difference() {
  PolyCyl(CapOD,CapLength,CapSides);

  translate([0,0,(Spacer + PlateThick)])					// lens shell
	PolyCyl(LensDia,(LensLength + Protrusion),CapSides);

  translate([0,0,-Protrusion])								// center hole
	PolyCyl(CenterHoleDia,(CapLength + Protrusion));

  translate([0,0,-Protrusion])								// bevel
	difference() {
	  cylinder(r=(CapOD/2 + 2*(BevelWidth + Protrusion)),
			   h=(2*BevelWidth + Protrusion),
			   $fn=CapSides);
	  cylinder(r1=(CapOD/2 - BevelWidth - Protrusion),
			   r2=(CapOD/2 + BevelWidth),
			   h=(2*BevelWidth + Protrusion),
			   $fn=CapSides);
	}

  difference() {
	translate([0,0,-Protrusion])							// cover plate recess
	  PolyCyl(PlateDia,(PlateThick + Protrusion));
	for (Index=[0:(NumStruts - 1)])							// support struts
	  rotate(Index*360/NumStruts)
		translate([-ThreadWidth,-SupportStrutLen,0])
		  cube([2*ThreadWidth,SupportStrutLen,PlateThick]);
  }
}

difference() {									// support ring
  PolyCyl(CenterHoleDia,PlateThick);
  translate([0,0,-Protrusion])
	PolyCyl((CenterHoleDia - 4*ThreadWidth),(PlateThick + 2*Protrusion));
}

The Logitech notebook webcam that peers into the Thing-O-Matic has terrible dynamic range compensation; turning on the LED ring light washes out the image something awful. An old Logitech ball camera seems better, but it sits atop a rubbery dingus adapted to grip huge old laptops. So I built an adapter with a standard 1/4-20 tripod screw thread in the bottom that ought to make it more useful.

The old & new mounts compared:

The color change comes from switching to yellow filament for an upcoming larger object.

The solid model shows those tiny little notches will require a bit of riffler file work:

The bottom has a blind 1/4-20 tapped hole. Lacking a bottoming tap, not having any broken 1/4-20 taps, and being unwilling to grind the end off a perfectly good taper tap, I filed three notches along a bolt. Ran the taper tap in until it hit bottom, ran the bolt in likewise, and defined the result to be Good Enough:

On the other end, the most probable failure will leave that delicate little post jammed firmly inside the camera’s socket. There’s not enough post to allow printing a small guide hole, but there’s no real need for one; I drilled a #50 hole right down the middle, ran a 2-56 screw into it without tapping the hole, and filed the screw head flat:

After cleaning up those notches, it snapped solidly into place:

And then the camera sits neatly atop a cheap Gorillapod knockoff:

That tiny reddish dot in the middle of the imposing set of rings marks the actual lens, so it’s more of a pinhole camera than anything else. The fixed focus kicks in beyond a meter, but a bit of rummaging in the Box o’ Lenses produced a random meniscus lens that pulled the focus in to maybe 100 mm. Alas, that means the camera must float in mid-air about 15 mm inside the Thing-O-Matic’s box. If I can conjure up a mount that holds the ball inside the box, above-and-forward of the stage, that’d work great. VLC can allegedly rotate the image upside-down, so maybe I can mount it bottom-up.

Here’s everything I know about those two cameras, with the ball camera on top and the webcam on the bottom:

Apparently it’s easier to put that information on a tag than provide a good old data plate on the camera body.

The OpenSCAD source code:

// Tripod mount for Logitech ball camera
// Ed Nisley KE4ZNU - Oct 2011

include </home/ed/Thing-O-Matic/lib/MCAD/units.scad>
include </home/ed/Thing-O-Matic/Useful Sizes.scad>
include </home/ed/Thing-O-Matic/lib/visibone_colors.scad>

//-------
//- Extrusion parameters must match reality!
//  Print with +0 shells and 3 solid layers

ThreadThick = 0.33;
ThreadWidth = 2.0 * ThreadThick;

HoleFinagle = 0.2;
HoleFudge = 1.02;

function HoleAdjust(Diameter) = HoleFudge*Diameter + HoleFinagle;

function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);

Protrusion = 0.1;			// make holes end cleanly

//-------
// Dimensions

BallDia = 60.0;				// camera ball
BallRad = BallDia/2;

BaseDia = 16.0;				// interface at tripod surface
BaseRad = BaseDia/2;

BaseLength = 10.0;			// to base of ball

BoltDia = Tap025_20;		// standard 1/4-20 thread
BoltLength = 7.0;

StemLength = 8.5;
StemDia = 4.7;
StemRad = StemDia/2;

FlangeWidth = 6.6;
FlangeThick = 2.6;

NotchSectionDia = 1.4;		// toroid cross-section diameter
NotchSectionRad = NotchSectionDia/2;
NotchOffset = 2.3;			// from top of stem

//-------

module PolyCyl(Dia,Height,ForceSides=0) {			// based on nophead's polyholes

  Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);

  FixDia = Dia / cos(180/Sides);

  cylinder(r=HoleAdjust(FixDia)/2,h=Height,$fn=Sides);
}

module ShowPegGrid(Space = 10.0,Size = 1.0) {

  Range = floor(50 / Space);

	for (x=[-Range:Range])
	  for (y=[-Range:Range])
		translate([x*Space,y*Space,Size/2])
		  %cube(Size,center=true);

}

//-------
//

ShowPegGrid();

translate([0,0,BaseLength])
  union() {
	difference() {
	  translate([0,0,-BaseLength])
		cylinder(r=BaseRad,h=2*BaseLength);
	  translate([0,0,BallRad])
		sphere(r=BallRad);
	  translate([0,0,-(BaseLength + Protrusion)])
		PolyCyl(BoltDia,(BoltLength + Protrusion));
	}
	rotate(180/16)
	  cylinder(r=StemRad,h=StemLength,$fn=16);
	difference() {
	  translate([0,0,StemLength/2])
		cube([FlangeWidth,FlangeThick,StemLength],center=true);
	  translate([0,0,(StemLength - NotchOffset)])
		rotate_extrude(convexity=3,$fn=64)
		  translate([FlangeWidth/2,0,0])
			circle(r=NotchSectionRad,$fn=16);
	  translate([0,-FlangeWidth/2,StemLength + sqrt(FlangeWidth)])
		rotate([0,45,0])
		  cube(FlangeWidth + 2*Protrusion);
	  translate([0,FlangeWidth/2,StemLength + sqrt(FlangeWidth)])
		rotate([0,45,180])
		  cube(FlangeWidth + 2*Protrusion);
	}
  }