Satco PAR30 LED Floodlight vs. Halogen

I replaced a dead 75 W halogen PAR30 bulb over the kitchen sink with a Satco S9415 LED bulb that was, at the time, advertised as “75 W equivalent”:

Satco S9415 PAR30 LED Bulb - specs

Satco S9415 PAR30 LED Bulb – specs

It’s noticeably less bright than the surviving halogen bulb, which is what you’d expect when 950 lm goes head-to-head with 1100+ lm (based on casual searching), but with a similar color temperature and beam pattern, so it’s Good Enough. I should have bought two and converted the halogens into glass sculptures.

The difference between the 22.8 year Life and the 3 Year Warranty always seems amusing. The warranty requires returning the bulb, so that’s about useless …


Kinesis Freestyle2 Keyboard vs. Linux

My old Microsoft Comfort Curve keyboard having gotten on in years, I picked up a Kinesis Freestyle2 (KB800B for PC) split keyboard:

Kinesis Freestyle2 - desk layout

Kinesis Freestyle2 – desk layout

The little hinged dingus (“Pivot Tether”) between the halves (“Keying Modules”) has two posts that pop into into sockets on the back of the halves and are retained by the two sliding latches. The cord connecting the halves allows 9 inches of separation; I don’t need that much, but more than zero seemed about right.

Kinesis also sells various staggeringly expensive (IMO) doodads that attach to the back of the keyboard to “tent” the middle upward with varying degrees of refinement. None of the doodads offer to raise the back of the keyboard, which I vastly prefer to the current flat or reverse-tilted recommendations.

The keyboard & trackballs rest on a homebrew shelf that slides out from where the desk used to have a center drawer, which puts the keyboard slightly above elbow height (heck, slightly above thigh height), whereupon tilting the keyboard puts the keys exactly where they should be. I bandsawed some wood into vaguely triangular sticks, topped them with foam sheets, and tinkered for best tilt. Works for me, anyhow.

The Compatibility section of the Freestyle2 User Manual describes the “special driverless hot keys”: Most will also work with Linux. Four of them do not work, to the extent that they don’t even send key codes to exv. Some searching suggests this is an intractable problem, for reasons that make no sense to me. Their HID Usage Codes, whatever that might mean:

Kinesis Freestyle2 - inert key codes

Kinesis Freestyle2 – inert key codes

That’s only a minor inconvenience; I prefer a physical calculator and don’t spend much of my life listening to anything through the headphones.

For whatever it’s worth, the scroll ring on the most recent warranty replacement Kensington Expert “Mouse” (I think it’s the third) has worked flawlessly for years; they seem to have fixed the sudden death syndrome.

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Sakura Micron Pen Widths

A bag of the Sakura Micron pens I was adapting for the HP 7475A plotter, before the generous donation of New Old Stock plotter pens arrived, come in a variety of useful widths:

Sakura Pens

Sakura Pens

This relentlessly organized doodle happened while reading some tech docs on the Comfy Couch:

Sakura Pen Width Examples

Sakura Pen Width Examples

The first two lines obviously belong in their own group, but, hey, it’s a doodle.

The two Uni-Ball Kuru Toga pencils, in 0.5 and 0.7 mm, have diamond-impregnated lead that’s supposed to be much more break-resistant than usual. I fear that they’ll land point-downward and wreck the rotating sleeve surrounding the lead, so I’ve managed zero drops so far. Even I hesitated at the 0.3 mm version.

They had me at “0.20 mm”



Sony HDR-AS30V vs. Lithium Ion 18650 Cells

These items came near enough to produce an irresistible force:

Sony HDR-AS30V vs 18650 cells - side view

Sony HDR-AS30V vs 18650 cells – side view

How can you look at that layout and not jump to the obvious conclusion?

The front view suggests enough room for a stylin’ case:

Sony HDR-AS30V vs 18650 cells - end view

Sony HDR-AS30V vs 18650 cells – end view

You’d need only one cell for the camera; I happened to have two in my hand when the attractive force hit.

The camera is 24.5 ⌀ x 47 tall x 71.5 overall length (67.8 front-to-door-seating-plane).

The ATK 18650 cells are 19 ⌀ x 69 long, with the overlong length due to the protection PCB stuck on the + end of the cylinder. You can get shorter unprotected cells for a bit less, which makes sense if you’re, say, Telsa Motors and building them into massive batteries; we mere mortals need all the help we can get to prevent what’s euphemistically called “venting with flame“.

Although I like the idea of sliding the cell into a tubular housing with a removable end cap, it might make more sense to park the cell over the camera in a trough with leaf-spring contacts on each end and a lid that snaps over the top. That avoids threaded fittings, figuring out how to get an amp or so out of the removable end cap contact, and similar imponderables.

think it’s possible to drill a hole through the bottom of the camera at the rear of the battery compartment to pass a cable from a fake internal cell to the external cell. Some delicate probing will be in order.

In round numbers, those 18650 cells allegedly have three times the actual capacity of the camera’s flat battery and cost about as much as the not-so-cheap knockoff camera cells I’ve been using.


J5 V2 Flashlight: Current Draw

Just for fun, I measured the J5 V2 flashlight’s current, by the simple expedient of unscrewing the cap and bridging the battery-to-case-threads gap with a multimeter:

J5 V2 Flashlight - negative cell terminal

J5 V2 Flashlight – negative cell terminal

The results:

  • High: 3 A
  • Medium: 1.5 A
  • Low: 0.7 A

As nearly as I can tell, they’re connecting the 18650 cell directly across the LED for High and PWM-ing it down to 50% and 25%. The PWM frequency is low enough to be visible during eye saccades and flashlight motions.

The flashlight knows how to do all five modes without its tail cap, so the controller + FET must live behind the LED. I can’t tell if the switch in the tail cap is just a dumb pushbutton (with, it seems, a surprising & ill-controlled resistance) or doing something clever with resistive levels (because the resistance varies with each push); at some point this thing will fail in an amusing manner and I’ll take it apart to find out.

The High setting dissipates 11 W (!) that pushes the flashlight well beyond uncomfortably warm within five minutes, so that’s not a useful long-term setting. The little alien egg beside the LED melted into a puddle during those five minutes; at least it won’t be moving anywhere else.

Setting it to Low = 25% PWM duty cycle = 0.7 A (average, sorta-kinda), a freshly charged 18650 cell lasts for about five hours down to 3.6 V, which is pretty close to the cell’s 3.4 A·h rating (kinda-sorta, ignoring the decreasing cell voltage, etc). That suggests Medium would last maybe two hours, tops, and there’s not enough heatsinking to discover how long High would last.

After 8.5 hours the cell was down to 3.2 V and the LED was, as you’d expect, rather dim. You could click to High for more light, of course, trading off runtime for brightness.

The square LED emitter array produces a square light pattern that’s not aligned with the flats on the body, so if you happened to be thinking of clamping a holder onto those flats, be prepared for some custom rotation to align the pattern with the outside world. That obviously doesn’t matter in a hand-held flashlight, but a bike headlight might look weird.

The zoom slider goes from a focused square (at full extension) to a well-filled round disk (at minimum length) with a diameter about five times the square’s side. I think the smooth zoom motion comes from grease-on-O-ring viscosity rather than precision machining.

The original back of the envelope data:

J5 V2 Flashlight - current and runtime

J5 V2 Flashlight – current and runtime


Mica Compression Capacitor: Unsolderable Pins

The mica compression capacitors have a finish on the pins that turned out to be completely un-solderable:

Mica compression capacitor - solder vs pin

Mica compression capacitor – solder vs pin

Some casual searching suggests this is a problem with sulfur contamination of the tin-lead solder layer. I can’t vouch for any of that, as the flat areas forming the capacitor seem to be silver-plated, but …

After some flailing around, I completely disassembled the capacitor, applied 800 grit sandpaper to remove all of the solder / flux / corrosion / tarnish / surface plating from the pins, dabbed on some RMA flux, then applied a thin layer of solder to both sides. Fortunately, the capacitor could be disassembled; they don’t make ’em like that any more.

The solder layers must be thin, because the slots in the ceramic base must pass two or three pins apiece: four or six solder layers add too much thickness. Solder-wick is my friend!

For reference, the 700 pF side looks like this:

Mica compression capacitor - 700 pF disassembled

Mica compression capacitor – 700 pF disassembled

The steel washer does not have a mica washer underneath (as does the washer on the 400 pF right side). The two grayish steel plates go on the top.

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Insouciant Squirrel

Squirrels spend most of their time on all fours and, when they do pop up for a look around, generally seem hunched forward, ready to drop-and-run.

Not this critter:

Squirrel leaning back

Squirrel leaning back

Definitely brandishing a big leaning ‘tude