Category: Photography & Images

Taking & making images.

Tour Easy: Another SJCAM C100+ Mount
Eight years of progress in the action camera world gets you from a rather expensive Cycliq Fly6:

Tour Easy – Fly6 image

To an SJCAM C100+ camera costing the better part of fifty bucks on closeout:

Tour Easy – C100 image

The camera is mounted on the side of the seat frame on Mary’s Tour Easy:

Tour Easy C100 mount – side rail

The slightly tilted picture comes from the frame rail’s incline. My C100+ camera mounts on the horizontal part of the rail:

Tour Easy C100 mount – rear rail

As expected, the internal battery does not last for our usual hour-long rides, so the cameras now operate in “car mode”: recording starts when we plug in the USB battery pack and stops shortly after unplugging.

I started with the waterproof case on my bike:

Tour Easy – SJCAM C100 mount – installed

Which (obviously) does not allow for an external battery, so they’re now in the “frame” mount. The hatch covering the MicroSD card and USB Micro-B connector (and a Reset button!) is on the bottom of the camera, but (fortunately) the whole affair mounts up-side-down and the settings include an image flip mode.

Putting the camera on the side required changing the mount angle from -20° to +35°:

SJCAM C100 Mount – 35 degree solid model

The ergonomics / user interface of this whole setup is terrible:
- The camera’s flexible hatch is recessed inside the frame far enough that it cannot be opened without using a small & sharp screwdriver
- The USB jack is slightly off-center, so lining the plug up with the camera body doesn’t align it with the jack
- The MicroSD card is in a push-to-release socket, but its raised ridge faces the hatch flap and cannot be reached by a fingernail. I added a small tab that helps, but it’s difficult to grasp.
Extracting the video files from the camera through the app is an exercise in frustration. Having already figured out how to do this for the other cameras in the fleet, it’s easier to fumble with the MicroSD card.

I devoutly hope we never really need any of the videos.
2023-05-23
HW Bucked Lithium AA Cells

The trail camera uses two parallel banks of four series AA cells to get enough oomph for its IR floodlight. I’m not convinced using bucked lithium AA cells in that configuration is a Good Idea, but it’s worth investigating.

These are labeled HW, rather than Fuvaly, because it seems one cannot swim twice in the same river:

HW bucked Li AA cells

In any event, they come close to their claimed 2.8 W·hr capacity:

HW bucked Li AA – 2023-05

The lower pair of traces (red & black) are single cells at 2.7-ish W·hr, the blue trace is a pair at 5.4 W·hr, and the green trace is a quartet at 9.8 W·hr. Surprisingly close, given some previous results in this field.

Recharging the cells after those tests shows they all take 3 hours ± a few minutes to soak up 730 mA·hr ± a few mA·hr, so they’re decently matched.

Measuring the terminal voltage with a 10 mA load after that charge lets me match a pair of quartets to 1 mV, which is obviously absurd:

HW bucked Li cells – initial charge 2023-05-05

The numbers in the upper left corner show the initial charge of four cells at a time required the same time within a minute and the same energy within 4%.

Sticking them in the trail camera must await using up the current set of alkaline AA cells.

Bonus: a lithium fire in a trail camera won’t burn down the house.

After all, pictures like this are definitely worth the hassle:

Young Buck in velvet – 2023-05-03

Looks like a pair of WiFi antennas …

2023-05-11
Trail Camera: Skunk

We’ve never seen a skunk by day, so this was a bit of a surprise:

Skunk by night

We occasionally smell a skunk by night, but this critter seems peaceable enough:

Skunk by night – detail

Skunks usually have a striped back, so this one’s pure white fur will be easy to identify should we meet again, ideally at a mutually respectful distance.

2023-04-24
SJCAM M50 Trail Camera: Dead Remote

The remote control included with the SJCAM M50 trail camera did absolutely nothing. Not only did it not turn on the camera’s WiFi, the two indicator LEDs between the buttons didn’t blink:

SJCAM M50 remote – front view

With not much to lose, I removed those four screws and popped the back cover:

SJCAM M50 remote – interior

Yup, the OEM no-name CR2032 lithium cell was dead flat discharged. A new one perked it right up, with blinky LEDs and all.

Now I can check the camera for interesting pix without hauling it into the house:

The Early Raccoon

Plenty of critters making the rounds out there …

2023-04-11

Tour Easy: SJCAM C100+ Mount

The batteries (which are no longer available) and the control buttons have worn out on the SJCAM M20 camera on the back of my Tour Easy, so a replacement is in order:

It’s an SJCAM C100+ in its waterproof housing, screwed to a block descended from the M20 mount:

SJCAM C100 Mount - solid model — SJCAM C100 Mount – solid model

The C100+ has a non-replaceable lithium pouch battery that may not last for the hour or so we generally ride, but at least this is a starting point for seeing how the thing works.

The PrusaSlicer preview shows the support structure inside the seat rail arches:

SJCAM C100 Mount - slicer — SJCAM C100 Mount – slicer

That appears under the four central facets of each arch, where I “painted” the support enforcers, because the automagic supports fill the entire arch and are basically impossible to pry off.

The hole between the ears on the top holds an aluminum tab intended to diffuse the wobble from that tall camera. A laser-cut chipboard template simplified drilling & cutting the tab from an aluminum sheet:

Tour Easy - SJCAM C100 mount - test fit — Tour Easy – SJCAM C100 mount – test fit

The tab and the brass inserts are held in place with JB Weld Plastic Bonder, my new go-to adhesive for such things.

The camera includes WiFi and the inevitable app lets you download images without opening the case. Because I’ll be charging the camera after each ride, I may as well just haul the whole thing inside, plug it into a USB port, and proceed as before.

For future reference, the manual details the operating modes:

SJCAM C100 Manual - Modes — SJCAM C100 Manual – Modes

Because the camera powers up with WiFi enabled and I have no plans to communicate with it while riding, the startup sequence will be:

Long-press to power on
Double-click to disable WiFi
Single-click to start recording

The OpenSCAD source code as a GitHub Gist:

	// SJCAM C100+ Camera Mount for Tour Easy seat back rail
	// Ed Nisley – KE4ZNU
	// 2023-04

	/* [Layout Options] */

	LookAngle = -20; // camera angle, looking backwards = 0°

	Layout = "Show"; // [Show,Build]


	/* [Hidden] */

	ThreadWidth = 0.40;
	ThreadThick = 0.25;

	HoleWindage = 0.2;

	Protrusion = 0.1;

	ID = 0;
	OD = 1;
	LENGTH = 2;

	//—–
	// Dimensions

	ClampScrew = [5.0,10.0,40.0]; // ID=thread OD=washer LENGTH=total
	ClampInsert = [5.0,7.5,10.5]; // brass insert

	MountScrew = [5.0,10.0,23.0]; // ID=thread OD=washer LENGTH=under nut
	MountInsert = [5.0,7.5,10.5]; // ID=screw OD, OD=knurl dia

	EmbossDepth = 2*ThreadThick + Protrusion; // recess depth + Protrusion beyond surface

	DebossHeight = EmbossDepth; // text height + Protrusion into part

	RailOD = 20.0; // slightly elliptical in bent section
	RailSides = 234;

	ClampOA = [60.0,40.0,ClampScrew[LENGTH]]; // set clamp size to avoid weird screw spacing
	echo(ClampOA = ClampOA);

	ClampScrewOC = IntegerMultiple(ClampOA.x – ClampScrew[OD] – 10*ThreadWidth,1.0);
	echo(ClampScrewOC = ClampScrewOC);

	ClampOffset = 5.0; // in case we need more room on top

	ClampRadius = 3.0;
	ClampSides = 8;

	Kerf = 1.0; // slice through the middle

	// center mount blade, Z = depth into block
	MountBlade = [15.0 + 2*HoleWindage,
	3.0 + 2*HoleWindage,
	(ClampOA.z – RailOD + ClampOffset)/2 – 4*ThreadThick + Protrusion];
	echo(MountBlade = MountBlade);

	MountRadius = MountBlade.x / 2;

	MountGap = 9.5; // camera mount gap around center blade

	MountOffset = [0,0,7.0]; // mount hole offset from block surface

	FadeColor = "Green";
	FadeAlpha = 0.25;

	//—–
	// Useful routines

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

	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=(FixDia + HoleWindage)/2,
	h=Height,
	$fn=Sides);
	}


	//—–
	// Clamp
	// Grips seat frame rail
	// Origin at middle of seat rail, X rearward, Y parallel to seat frame rail
	// Block offset raises whole thing

	module Clamp() {

	difference() {
	translate([0,0,ClampOffset]) {
	difference() {
	union() {
	hull() // the main block
	for (i=[-1,1], j=[-1,1], k=[-1,1])
	translate([i(ClampOA.x – 2ClampRadius)/2,
	j(ClampOA.y – 2ClampRadius)/2,
	k(ClampOA.z – 2ClampRadius)/2])
	sphere(r=ClampRadius/cos(180/ClampSides),$fn=ClampSides);

	hull() // camera mount boss
	for (k=[0,1])
	translate([0,0,k*(MountOffset.z) + ClampOA.z/2])
	rotate([0,90,LookAngle + 90]) rotate(180/12)
	cylinder(r=MountRadius,h=MountScrew[LENGTH],center=true,$fn=12);

	}

	for (i=[-1,1]) // clamp inserts
	translate([i*ClampScrewOC/2,0,-(ClampOA.z/2 + Protrusion)])
	rotate(180/6)
	PolyCyl(ClampInsert[OD],ClampInsert[LENGTH],6);

	for (i=[-1,1]) // clamp screw holes
	translate([i*ClampScrewOC/2,0,-ClampOA.z])
	rotate(180/6)
	PolyCyl(ClampScrew[ID],2*ClampOA.z,6);

	translate([0,0,ClampOA.z/2 – (MountBlade.z/2 – Protrusion/2)]) // camera center blade
	rotate(LookAngle)
	cube(MountBlade,center=true);

	rotate(LookAngle + 90) // camera mount boss slot
	translate([0,0,ClampOA.z/2 + 2*MountRadius])
	cube([MountGap,4MountRadius,4MountRadius],center=true);

	translate([0,0,ClampOA.z/2 + MountOffset.z]) // camera mount boss hole
	rotate([90,0,LookAngle])
	cylinder(d=MountScrew[ID],h=4*MountGap,center=true,$fn=6);

	translate([0.3*ClampOA.x, // recess for LookAngle legend
	-(ClampOA.y/2 – (EmbossDepth – Protrusion)/2),
	ClampOA.z/4])
	cube([15,EmbossDepth,8],center=true);

	translate([0,0,-ClampOA.z/2 + (EmbossDepth – Protrusion)/2]) // recess for ID legend
	cube([35,10,EmbossDepth],center=true);
	}

	translate([0.3*ClampOA.x, // LookAngle legend
	-ClampOA.y/2 + DebossHeight + Protrusion/2,
	ClampOA.z/4])
	rotate([90,0,00])
	linear_extrude(height=DebossHeight,convexity=20)
	text(text=str(LookAngle),size=6,spacing=1.20,
	font="Arial:style:Bold",halign="center",valign="center");

	translate([0,0,-ClampOA.z/2]) // ID legend
	linear_extrude(height=DebossHeight,convexity=20)
	mirror([0,1,0])
	text(text="KE4ZNU",size=5,spacing=1.20,
	font="Arial:style:Bold",halign="center",valign="center");
	}

	cube([2ClampOA.x,2ClampOA.y,Kerf],center=true); // split across rail

	rotate([90,0,0]) // seat rail
	cylinder(d=RailOD,h=2*ClampOA.y,$fn=RailSides,center=true);

	}
	}

	//—–
	// Build things

	// Layouts for design & tweaking

	if (Layout == "Show") {
	Clamp();
	color(FadeColor,FadeAlpha)
	rotate([90,0,0])
	cylinder(d=RailOD,h=2*ClampOA.y,$fn=RailSides,center=true);
	}


	// Build layout

	if (Layout == "Build") {
	translate([0,0.7*ClampOA.y,0])
	difference() {
	translate([0,0,-Kerf/2])
	Clamp();
	translate([0,0,-ClampOA.z])
	cube(2*ClampOA,center=true);
	}
	translate([0,-0.7*ClampOA.y,-0])
	difference() {
	translate([0,0,-Kerf/2])
	rotate([0,180,0])
	Clamp();
	translate([0,0,-ClampOA.z])
	cube(2*ClampOA,center=true);
	}
	}

view raw SJCAM C100 Mount.scad hosted with ❤ by GitHub

2023-04-05

The Early Opossum

Having just deployed a trail camera to see what might be skulking about in the middle of the night, this appeared just before the (not fresh) batteries died:

The Early Opossum

It’s hard to tell with possums, but I’d say that critter is on a mission!

I’m still figuring out proper distances; the possum is about two feet away, which is obviously much too close. Great focus on the water barrels standing by the garage, though.

2023-03-29
Medium Ricotta Lid Box: QR Code vs. Chipboard
Another box from the festi.info box configurator to collect more lids in a kitchen drawer:

Medium Ricotta Lids box

This was really a thinly veiled excuse for a deeper look at the QR code generator encoding the myriad parameters required to create the box and see what happens when you try to burn such a complex thing into chipboard.

Spoiler: chipboard has very low contrast and really does not work well with high-density QR codes.

Although the festi.info box generator can produce QR codes, I used qrencode (available in your Linux distro) on the command line to generate QR code image files with specific settings:
```
qrencode --level=M --size=6 --dpi=254 --output='Ricotta Lids 2 lb - chipboard.png' 'http://festi.info/boxes.py/ABox?FingerJoint_angle=90.0&FingerJoint_style=rectangular&FingerJoint_surroundingspaces=2.0&FingerJoint_bottom_lip=0.0&FingerJoint_edge_width=2.0&FingerJoint_extra_length=0.0&FingerJoint_finger=2.0&FingerJoint_play=0.0&FingerJoint_space=3.0&FingerJoint_width=1.0&x=200.0&y=120.0&h=60.0&outside=0&bottom_edge=h&thickness=1.4&format=lbrn2&tabs=0.0&qr_code=0&debug=0&labels=0&reference=0&inner_corners=corner&burn=0.04&language=en&render=0'
```
The key parameters:
- --level → error correction level
- --size → size of the smallest square (“module”) in pixels
- --dpi → DPI of the output image file
The default file type is PNG. The unusual 254 DPI makes each pixel exactly 0.1 mm wide and a peculiar 169.33 DPI = 0.15 mm came in handy for the first pattern.

The final parameter is the character string to encode, which you should definitely quote to prevent the shell from wrecking things while trying to help you.

A pattern with 4×4 pixel modules didn’t scan at all:

Chipboard QR code – 15pct 0.15mm 4×4 – overview

A closer look shows the modules have ragged edges due to laser timing variations during the engraving scans and gaps between successive scans because the spot size is less than the 0.15 mm scan interval:

Chipboard QR code – 15pct 0.15mm 4×4 – detail

Increasing the module to 6×6 pixels at a 0.1 mm scan interval :

Chipboard QR code – 15pct 0.10mm 6×6 – overview

A closer look shows the larger module reduces the relative size of the timing errors, while the decreased line spacing tidies up the blocks:

Chipboard QR code – 15pct 0.10mm 6×6 – detail

Reducing the power from 15% to 10% reduced the contrast to the point of illegibility:

Chipboard QR code – 10pct 0.10mm 6×6 – overview

A closer look shows the engraving barely punches through the surface and has somewhat more ragged edges due to the tube’s pulsating startu p current at very low power:

Chipboard QR code – 10pct 0.10mm 6×6 – detail

I also tried 5×5 modules with similar results.

The laser spot size sets the engraving scan interval, which then determines the DPI value for the QR code image. With all that matched up, you can send the images directly to the laser in Passthrough mode, without having LightBurn resample the pixels and change the module’s shape.

Looked at from a different angle: given the laser spot size and the module size, the QR code image size is not under your control.

From another angle: given a QR code image size in, say, millimeters, and the engraving scan interval, the module size is not under your control.

All this is moot if you print QR codes on a high-resolution / high-contrast printer. It’s just the gritty nature of laser cuttery that limits what you can accomplish.

And, of course, using a material less awful than chipboard will definitely improve the results.

If you want a similar box of your own, here ya go:

Medium Ricotta Lids – chipboard QR code – default

The URL is too ugly to print, but you can copy it from this link.
2023-03-16