The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Category: Electronics Workbench

Electrical & Electronic gadgets

  • SJCam M50 Trail Camera: Battery Wire FAIL

    SJCam M50 Trail Camera: Battery Wire FAIL

    My SJCam M50 Trail Camera has had its share of problems, including water making it past the seals to corrode some connections:

    M50 Trail Cam - contact corrosion
    M50 Trail Cam – contact corrosion

    I thought cleaning that mess up would solve an intermittent power problem, but the camera continued to fail immediately after being deployed and finally refused to work at all.

    The camera case has eight (!) AA cells in one half connected to the electronics in the other half by a pair of wires that pass through the hinge between the halves:

    M50 Trail Cam - pivot wire route
    M50 Trail Cam – pivot wire route

    The steel rod is the hinge pivot, with the battery half wearing brown and the electronics half in lighter plastic. As you’ll see in a bit, the rod is fixed in the electronics half and the battery half pivots around it.

    The two short case sections on the right contain the two wires carrying the 6 V battery power. Some gentle manipulation suggested the fault lay inside those hinge sections, which meant I had to figure out how to get them apart.

    The other end of the steel rod has a knurled section jammed firmly into the electronics half, but I managed to carve away just enough plastic to expose just enough of the knurl to get just enough of a grip (yes, with a pair of genuine Vise-Grip 10WR Locking Pliers, accept no substitutes) to yoink the rod out:

    M50 Trail Cam - extracted pivot
    M50 Trail Cam – extracted pivot

    With the hinge released, the problem became immediately obvious:

    M50 Trail Cam - failed hinge wires
    M50 Trail Cam – failed hinge wires

    Yes, those are wire strands poking out of the hole in the left hinge section.

    A tedious needle-nose tweezer session extracted the remains of the wires from the hinge and cleaned out the adhesive:

    M50 Trail Cam - extracted OEM PVC wires
    M50 Trail Cam – extracted OEM PVC wires

    Although those two hinge sections are hollow with plenty of room for the wire, it seems the assembler squirted adhesive into both sections to glue the wires in place. As a result, every time I opened the case to charge the batteries, maybe two millimeters of wire twisted 180° degrees. The wonder is that it lasted as long as it did.

    I snaked a pair of 20 AWG silicone-insulated wires through the hinge sections:

    M50 Trail Cam - silicone rewiring
    M50 Trail Cam – silicone rewiring

    The OEM wires had PVC insulation, which is a terrible choice for wires that will undergo lots of flexing, but that’s what SJCam used.

    Two untidy blobs of acrylic caulk do at least as good a job of sealing the case openings as the black gunk visible in the earlier pictures:

    M50 Trail Cam - new caulk
    M50 Trail Cam – new caulk

    I left all of the wire in the hinge un-stuck, hoping the twist will distribute itself over maybe 5 mm of wire and last longer.

    In anticipation of future repairs, however, I left enough of the knurled end of the hinge rod exposed to get an easy grip:

    M50 Trail Cam - restaked pivot
    M50 Trail Cam – restaked pivot

    Solder the new wires to the old pads, assemble in reverse order, and it works as well as it ever did:

    The alert reader will note I did not reset the camera clock after charging the batteries, a process requiring the janky SJCam app.

    The two finches on the right have been constructing a nest in the wreath hanging at our front door. They tolerate our presence, although they’d be happier if delivery folks dropped packages elsewhere.

  • Skil Cordless Driver Re-batterying

    Skil Cordless Driver Re-batterying

    In anticipation of upcoming disassembly & reassembly tasks, I finally replaced the long-dead NiCd battery in an old Skil cordless driver with an 18650 lithium cell from the Basement Warehouse Wing:

    Skil Cordless Driver - 18650 cell overview
    Skil Cordless Driver – 18650 cell overview

    A USB charge controller sits in a slot carved into the plastic formerly supporting the NiCd battery’s charging jack:

    Skil Cordless Driver - USB charger detail
    Skil Cordless Driver – USB charger detail

    Hot-melt glue holds everything in place.

    The motor draws about 2 A under full load, which is a bit more than the charge controller wants to supply. I simply wired the motor (through its reversing switch) directly to the 18650 cell terminals, which is certainly not good practice, but seems reasonable given the intended use case.

    A red LED shows the charger stuffing energy into the cell:

    Skil Cordless Driver - charge indicator
    Skil Cordless Driver – charge indicator

    You can see the blob of glue holding one of the acrylic cylinders left over from the gelatin capsule filler; only 99 more to go! I had to turn it down by about a millimeter, an operation best left to your imagination.

    After an hour, a green glow shows the cell is fully charged:

    Skil Cordless Driver - full charge
    Skil Cordless Driver – full charge

    The original label proudly touted the NiCd battery’s 2.4 V, so I figured truth in packaging required a new label:

    Skil Cordless Driver - new label cutting
    Skil Cordless Driver – new label cutting

    The process:

    • Scan the original labels
    • Blow out the contrast to make binary masks
    • Trace into vectors with LightBurn, simplify & clean up
    • Add targets for Print-and-Cut
    • Save as SVG, import into GIMP, lay out text, print
    • Cut the outlines

    The labels have laminating film on the top and craft adhesive on the bottom, both of which cut neatly and look pretty good:

    Skil Cordless Driver - lithium in action
    Skil Cordless Driver – lithium in action

    The alert reader will note the 4+ V from a fully charged lithium cell exceeds the 2.4+ V from fully charged NiCd cells, which accounts for the very bright incandescent headlamps. I figure 4 is roughly equal to 2.4, for large values of 2.4: the driver ticks along at 170 RPM instead 140 RPM.

    I measured the torque using a double-ended hex bit in a torque screwdriver, with the torque setting cranked up until the driver just barely clicked it over.

    I took the liberty of filing the raised “2.4 V” off the hinge covers and adding tidy retroreflective disks:

    Skil Cordless Driver - hinge cover
    Skil Cordless Driver – hinge cover

    I briefly considered adding “3.7 V” (because “4.2 V MAX” wouldn’t fit) in laser-cut PSA vinyl, but it was getting late.

    Now I can screw things up in style …

  • Hiatus

    Hiatus

    The sellers have accepted our offer on their house, so over the course of the next couple of months we’ll be moving, then selling this place. Having begun dismantling and packing the contents of the Basement Shop, Laboratory, and Warehouse, my blog-worthy activities will grind to a temporary halt.

    Should you or anyone you know be interested in moving to the trendy Hudson Valley region, we have a conveniently located property with a shop-ready basement:

    2108-2110 New Hackensack Rd - Streetview 2023-08
    2108-2110 New Hackensack Rd – Streetview 2023-08

    Maybe we can make a deal …

  • Laser Cutter Camera: USB Mystery

    Laser Cutter Camera: USB Mystery

    The USB camera stuck inside the lid of the laser worked fine:

    OMTech Laser - camera mount
    OMTech Laser – camera mount

    Until a month or two ago, when it began disconnecting randomly.

    The camera cable has a standard USB A connector on one end and what looks like a 1.5 mm JST ZH connector on the other:

    Laser cutter camera cable
    Laser cutter camera cable

    Of course, it’s not quite long enough, so it plugs into a good-quality 1 meter USB 3.0 extender to the PC sitting atop the laser cabinet.

    Some low-effort tweaks were unavailing:

    • Different USB ports
    • Different USB extension cable to the ports
    • Hub vs. direct

    Eventually, some rummaging in the Box o’ USB Cables produced a cable from a different camera and, as you might expect, swapping the two identical cables solved the problem.

    I have no idea what’s going on, but I’d lay significant money that when this cable gets flaky, swapping the original cable back in will solve the problem once again.

  • Magazine Dump: Insuperable Opportunity

    Magazine Dump: Insuperable Opportunity

    For reasons that will become relevant later on, I must clear the magazines from about ten feet of shelf space (and a stack of boxes), including this assortment:

    Magazine Dump
    Magazine Dump

    What you see:

    To the best of my knowledge and belief, each collection is complete within those dates, although I’m equally sure an issue or two went walkabout over the course of four decades.

    Having written columns for Digital Machinist, DDJ, and Circuit Cellar, I (still!) have multiple “author’s copies” of those, although I haven’t dug through the boxes for the specifics.

    Here’s the deal:

    • You must take all of any set
    • Any offer ≥ $0.00 is acceptable
    • Shipping from ZIP 12603 is your problem
    • N.B.: Shipping Is Not My Problem (*)

    Best offer on or before 30 November 2023 takes any or all.

    Whatever remains becomes mulch in December 2023.

    (*) A USPS Medium Flat Rate box (11×8.5×5.5 inch) costs $17 within the continental US and holds two or three dozen issues. Obviously, that’s the wrong way to ship an entire shelf of magazines, but gives you an idea of the scale.

    If you want to pick ’em up in person, I’ll help heave ’em into your trunk.

  • Nuheara IQbuds² MAX Battery Replacement

    Nuheara IQbuds² MAX Battery Replacement

    Nuheara predicts two to three years of battery lifetime for their IQbuds² MAX not-really-hearing-aids and, indeed, after 2-½ years of more-or-less steady use, the right bud developed a bad case of not charging fully and discharging quickly. The batteries are not, of course, customer-replaceable, so one can:

    • Buy a single bud
    • Buy a complete new pair + case + accessories
    • Ask about their repair service

    Unsurprisingly, a single bud costs more than half the cost of the full set and the repair service is a complete mystery. Given that the left bud’s battery will likely fail in short order, let’s find out what’s inside.

    Your ear sees this side:

    Nuheara IQbud - bottom view
    Nuheara IQbud – bottom view

    The dark oval is a (probably IR) sensor telling the bud when it’s jammed in your ear.

    Everybody else sees this side:

    Nuheara IQbud - top view
    Nuheara IQbud – top view

    The small slit over on the right and the two holes around the top seem to be for various microphones.

    Jamming a plastic razor blade into the junction between the two parts of the case, just under the mic slit, and gently prying around the perimeter eventually forces the adhesive apart:

    Nuheara IQbud - case splitting
    Nuheara IQbud – case splitting

    Do not attempt to yank the two pieces apart, because a ribbon cable joins the lower and upper PCBs:

    Nuheara IQbud - ribbon cable
    Nuheara IQbud – ribbon cable

    The metallic disk in the lower part is the lithium battery.

    Ease the upper part away, being very careful about not tugging on the ribbon cable:

    Nuheara IQbud - raising battery
    Nuheara IQbud – raising battery

    The battery has moved upward, revealing the lower PCB.

    Rolling the upper part toward the ribbon cable eventually produces enough space to extract the battery:

    Nuheara IQbud - battery freed
    Nuheara IQbud – battery freed

    Note the orientation:

    • The rebated end is the negative terminal and faces outward
    • The wider end is the positive terminal and faces inward

    With the battery out, you can admire the PCBs and ribbon cable:

    Nuheara IQbud - interior view
    Nuheara IQbud – interior view

    What is not obvious from the picture: two pairs of spring-loaded pogo pins contacting the battery. There is no actual battery holder, as it’s just tucked into the structure of the bud, with the perimeter adhesive providing the restraining force for the pogo pins.

    The battery seems a variant of a standard 1654-size lithium cell:

    Nuheara IQbud - OEM ZJ1654A lithium cell
    Nuheara IQbud – OEM ZJ1654A lithium cell

    The 1654 cells I got came with wire leads welded to the cell and a complete Kapton enclosure; apparently other devices use soldered connections rather than pins. They proudly proclaim their “Varta” heritage, but I have no way to prove they actually came from Germany.

    I snipped off the wires, carved a pair of holes through their Kapton for the contact pins, tucked the cell in the bud, pressed the halves together, applied a clamp, then wrapped a strip of Kapton tape around the perimeter:

    Nuheara IQbud - reassembled
    Nuheara IQbud – reassembled

    It seems remarkably easy to wrap the tape over the front microphone, but don’t do that. Conversely, sealing the entire perimeter is the only way to prevent acoustic feedback, so I added a snippet of tape just under the front mic opening.

    Do that for the other bud and declare victory.

    That is, fer shure, not the most stylin’ repair you’ve ever seen, but I was (for what should be obvious reasons) reluctant to glue the halves together. I expect the tape to peel off / lose traction after a while, but I have plenty of tape at the ready. Worst case, I can glop some adhesive in there and hope for the best.

    Because the buds lost power during their adventure, they required a trip through their charging case to wake them up again. After that, they work as well as they did before, with consistently longer run time from both buds.

    Whew!

  • Moonlander Keyboard vs. Board Chow

    Moonlander Keyboard vs. Board Chow

    The Moonlander keyboard has per-key LEDs that I’ve denatured enough that most show a pale gray, with a few others highlighted in orange. A few weeks ago the LEDs on the right-hand thumb cluster and the N key went nuts, cycling through a surprising assortment before settling on bright red; the obvious resets / firmware reflashing / tapping were all unavailing.

    ZSA’s tech support recommended taking the thumb cluster apart to check the ribbon cable connecting it to the main keyboard half:

    Moonlander thumb cluster - PCB bottom
    Moonlander thumb cluster – PCB bottom

    Come to find out my unclean personal habits lodged a particularly corrosive nugget of board chow on the cable:

    Moonlander - corroded ribbon cable
    Moonlander – corroded ribbon cable

    It’s a more-or-less standard 0.5 mm pitch cable, but only 20-ish mm long, much shorter than the cables carried by the usual sources. ZSA sells them for $2 each, plus $25 courier shipping, so I bought three; they arrived in two days from halfway around the planet.

    Because I don’t foresee my personal habits changing any time soon, I tucked a Kapton tape snippet in the gap to serve as a gutter:

    Moonlander thumb cluster - tape shield installation
    Moonlander thumb cluster – tape shield installation

    That’s with the two hinge screws out and the cluster eased down-and-away from the keyboard enough to get the tape pressed against the keyboard.

    With the screws installed and the cluster at its normal most-downward angle, the gutter closes up:

    Moonlander thumb cluster - tape shield folded
    Moonlander thumb cluster – tape shield folded

    With the cluster in its normal operating position (for me, anyway), the gutter is nearly invisible:

    Moonlander thumb cluster - normal position
    Moonlander thumb cluster – normal position

    For the record, I tucked the remaining ribbon cables inside the left-hand thumb cluster against future need.