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

  • IWISS SN-2549 Crimping Tool Instructions

    IWISS SN-2549 Crimping Tool Instructions

    Because I needed to know which of the four dies in the jaw of my IWISS SN-2549 crimper was the right one for 24 AWG ribbon cable:

    IWISS SN-2549 JST Crimper Manual
    IWISS SN-2549 JST Crimper Manual

    It turns out either of the two middle slots should work, but the crimps look better in the smaller one.

    Admittedly, the instructions are thin on technique, but I only wrecked four pins while retraining my crimping hand. The key trick is indexing the insulation fingers on the step inside the jaw, thus putting the socket box or the male pin outside where it won’t get smashed flat. Squishing those fingers from their normal splayed condition into a rectangular shape helps fit them into the jaw against the step.

    Living in the future where the right crimping tool doesn’t cost five Benjamins is great …

  • Baofeng UV-5 Wiring Plate Globbery

    Baofeng UV-5 Wiring Plate Globbery

    The weekly battery swap revealed the dismal state of the headset wires on Mary’s radio:

    Baofeng wiring plate - loose wires
    Baofeng wiring plate – loose wires

    That’s after sorting & disentangling loose ends, ramming cables under their ties, and generally tidying things up.

    Which suggested an improvement I should have done long ago:

    Baofeng wiring plate - globbed
    Baofeng wiring plate – globbed

    Verily, it is written: the bigger the blob, the better the job.

    Gotta glob my bike the next time around.

    Update: It’s hot melt glue!

  • Magnifying Desk Light: LED-ifying & Base Refooting

    Magnifying Desk Light: LED-ifying & Base Refooting

    My ancient fluorescent magnifying desk lamp emerged from a box and cried out to be used, but the equally ancient 22 W fluorescent ring light was long past its prime and cried out to be replaced with something from the current millennium.

    So I removed the fluorescent ballast / choke from the junction box at the lamp base:

    Magnifying Ring Light - ballast removed
    Magnifying Ring Light – ballast removed

    That’s a grounded outlet in the cover plate serving as a wire termination block. The red crimp connector joins a white wire that formerly went to the ballast with the black wire going to the lamp head; you’ll note the black wire from the line cord going into the same heatstink tubing at the outlet.

    The lamp head had a push-to-start switch, presumably with an internal starting capacitor or some such, but also sporting a pair of terminals behaving like a single-pole push-on / push-off switch. A bit of rewiring, of which there are no pictures, made it work perfectly with the new 13 W LED ring light:

    Magnifying Ring Light - LED ring installed
    Magnifying Ring Light – LED ring installed

    It now sits on a bit of laboratory ironmongery weighing about as much as a small child:

    Magnifying Ring Light - on base
    Magnifying Ring Light – on base

    Although the base has four feet, it sits perfectly flat on my (admittedly battered) surface plate because all four feet have been ground to make that happen:

    Magnifying Ring Light - foot plan view
    Magnifying Ring Light – foot plan view

    Those feet will be hostile to any table / bench top outside their intended laboratory environment. Fortunately, the geometry is simple enough to build directly in LightBurn and cut from a cork disk with PSA backing suited to become a coaster:

    Magnifying Ring Light - cork foot cutting
    Magnifying Ring Light – cork foot cutting

    Which fit well enough, although all four feet are just slightly different:

    Magnifying Ring Light - cork foot
    Magnifying Ring Light – cork foot

    The new Basement Shop™ is coming together and this stuff is getting easier …

    The WordPress AI came up with a plausible steampunk build:

    Magnifying Ring Light - WP AI image 1
    Magnifying Ring Light – WP AI image 1

    Love those flowy feet, although the vertical rod in the back seems misplaced.

    Adding “one-piece base” to the prompt produces contemporary style:

    Magnifying Ring Light - WP AI image 2
    Magnifying Ring Light – WP AI image 2

    Dunno what the dingus on the lower arm might be (perhaps a spring?), but it’s got the right general idea.

  • Samsung Microwave Gas Sensor Teardown

    Samsung Microwave Gas Sensor Teardown

    With the microwave back in operation, I thought I might learn something about the failed gas sensor:

    Figaro TGS880 - base
    Figaro TGS880 – base

    Given that much information, finding the datasheet for a Figaro TGS880 sensor didn’t require much effort. In case you were wondering, the replacement sensor has no trace of branding or identification.

    The sensor element has a resistance varying with gas concentration, for a variety of test gases I hope our kitchen never contains in such abundance:

    Figaro TGS-880 Gas Sensor - response plot
    Figaro TGS-880 Gas Sensor – response plot

    The measurement circuit:

    Figaro TGS-880 Gas Sensor - measurement circuit
    Figaro TGS-880 Gas Sensor – measurement circuit

    I betcha the microwave waits for an order-of-magnitude resistance drop from whatever the starting value might be, then calls it done.

    The belly band holding the steel mesh to the plastic base is no match for a Dremel slitting wheel:

    Figaro TGS880 - opening
    Figaro TGS880 – opening

    As the saying goes, Sensoria est omnis divisa in partes tres:

    Figaro TGS880 - teardown
    Figaro TGS880 – teardown

    A closer look at the sensor element:

    Figaro TGS880 - interior
    Figaro TGS880 – interior

    The granular surface does not get along well with the 5× digital zoom required to fill the phone’s sensor, but you get the general idea:

    Figaro TGS880 - element detail
    Figaro TGS880 – element detail

    The heater measured 30 Ω on the dot and the sensor was an open circuit on the 100 MΩ range. Connecting the heater to a 5 V supply dropped the sensor resistance to 800 kΩ @ 50 %RH and a warm breath punched it to about 2 MΩ. That’s with an ohmmeter because I haven’t yet unpacked the Electronics Bench, but seems far above the spec of 20-70 kΩ in air.

    So it’s still a sensor, even if it’s not within spec.

    The WordPress AI-generated image for this post is … SFnal:

    Figaro TGS-880 Gas Sensor - AI generated image
    Figaro TGS-880 Gas Sensor – AI generated image

    My pictures apparently aren’t up to contemporary blog standards …

  • Solar Yard Light Debris

    Solar Yard Light Debris

    A solar yard / walkway light appeared in the far back reaches of the yard while mowing:

    Solar yard light - bubble
    Solar yard light – bubble

    Yes, that’s an air bubble in the middle, so you know the light hasn’t been staying in its Happy Place™.

    As the djinn in the bottle put it, “Pop the top and let’s get started”:

    Solar yard light - cover off
    Solar yard light – cover off

    Those light emitting diodes around the photovoltaic cell in the middle can’t light up any more.

    A little more effort with the Designated Prydriver reveals the guts:

    Solar yard light - components
    Solar yard light – components

    That’s an NiMH cell, so the light has been abandoned out there for quite a few years.

    The photovoltaic element still worked, but the LEDs were defunct. The corpse will be a guest of honor at the next electronics recycling event down the road from here.

    Someday, our great-to-the-nth grandchildren will curse our ways …

  • Garage Opener Antenna Director

    Garage Opener Antenna Director

    By a quirk of fate, the Chamberlain garage door opener in our new house has the same “purple learn button” as the Sears opener in our old house, so I introduced it to our remotes and they work just fine.

    I then replaced the four-button remote in my bike pack with a new single-button remote to reduce the dexterity required to hit the button:

    Garage Opener - one button
    Garage Opener – one button

    Alas, the opener only responded when the remote was immediately outside the aluminum garage door. Checking the battery (because sometimes “new” does not mean what you think it means) reminded me we live in an age when hardware is free compared with bookkeeping:

    Garage Opener - interior
    Garage Opener – interior

    Maybe the second button doesn’t work and this is how they monetize their QC reject pile?

    I want the door to start moving when I’m at the end of the driveway, giving it enough time to get all the way up so I can bike right in. You can actually buy remote / extension antennas, although for fancier openers with SMA antenna connectors, but sometimes a little RF black magic will suffice:

    Garage Opener - crude antenna director
    Garage Opener – crude antenna director

    The wavy wire hanging down from the opener’s rear panel is the original antenna, which might be kinda-sorta omnidirectional. The opener operates around 433 MHz= 69 cm, so a quarter-wave antenna will be 17 cm = 7 inch long; the (unbent) wire is maybe 10 inches long from the hole in the panel.

    So I taped 11 inches of wire to the opener to form a very very crude Yagi-Uda antenna. It’s too long to be a director element, it’s about right (albeit in the wrong place) to be a reflector element, it might be neither.

    What it does do is warp the antenna’s pattern just enough to let the remote reliably trigger the opener as I approach the end of the driveway.

    Do not even begin to think about polarization mismatch from what looks like the tiny loop antenna on the remote’s PCB.

  • LED Light Switch: FAIL

    LED Light Switch: FAIL

    As a temporary expedient while awaiting more outlets in the basement, I screwed several hundred watts of LED strip lighting to the floor joists so I could see where I was going:

    First pass at basement lighting
    First pass at basement lighting

    The switch seemed to run warm, which I attributed to being snuggled up against one of the LED strips, eventually became intermittent, and finally failed with the lights out.

    Prying apart the snapped-together case destroyed it, but that didn’t really matter when I saw the innards:

    T8 LED power switch
    T8 LED power switch

    The “intermittent” action came from the melted post on the switch actuator at the top of the photo. The “warm” came from the barely crimped black wire on the right side of the switch, which *might* have had half a dozen strands caught in the flattened crimp triangles.

    I replaced it with an identical switch from the assortment that came with the lamps. That one seems to run cooler, although I doubt the crimps are really up to any reasonable quality standards.

    In addition to adding basement outlets & lighting circuits, the rest of the house has some electrical wiring peculiarities; the kitchen microwave really shouldn’t share a circuit with the dining room lights.