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.

Author: Ed

Splinting an Umbrella Strut
One of the ribs in the six-passenger umbrella we keep in the van snagged on something and snapped its fitting on the spreader strut:

Umbrella strut – broken connector

This being wonderful engineering plastic that cannot be solvent-bonded, epoxy is the only adhesive that will work. However, those joints undergo tremendous stress in a deployed umbrella, so a bare epoxy joint won’t have enough strength for the job. What to do?

Wonder of wonders, when I got the umbrella into the Basement Laboratory Repair Wing, I discovered:
- The not-quite-round strut fitting stub slipped right into a short brass tube from the heap and
- Just enough of the fitting remained on the rib to anchor the tubing
A silicone tape wrap kept most of the epoxy inside while it cured:

Umbrella strut – epoxy curing

Clearing off a few blobs made it all good:

Umbrella strut – brass tubing splint

We don’t play golf, but such a big umbrella keeps most of the rain off two people; it’s a tchotchke from back when Mary worked at IBM (hence the color scheme). We call it our “six-passenger” umbrella because it looks about that big when we deploy it…
2012-10-16
Monthly Picture: Laboratory Study of the Grasshopper

My father drew this in his Sophomore Biology Laboratory Notebook:

Laboratory Study of the Grasshopper

Can you imagine the attention span required to draw that with no obvious errors? The next four pages contain a hand-written discussion of the grasshopper, with two corrections; he filled the entire notebook using a pen and four colors of fluid ink.

Here’s a closer look at the grasshopper (clicky for more dots):

The Grasshopper

I cannot imagine assigning that task to present-day students…

Things were different in 1927, when he was 17 years old. They were about to get really different; 15 years later he was in the South Pacific.

2012-10-15
Grace Under Pressure

We toured the USS Albacore (AGSS 569) in Portland NH and found this placard in the forward Escape Trunk (which doubled as the normal hatch during the sub’s nautical lifetime):

Escape Trunk Operating Procedure

One of my relatives is a submariner who seems calm & collected enough to remember that entire checklist in an emergency.

The heads bore similar placards, along the lines of the classic scene in 2001: A Space Odyssey.

The camera lens they used for their virtual tour pictures would lead you to believe there was actually enough space inside the sub to inhale. That was not the case and I was very glad to have only half a dozen other people touring the sub with us.

Our hotel room (on the top floor of Wentworth by the Sea, egad) had a good view of the Portsmouth Naval Shipard (also see Wikipedia) across the Piscataqua River, where the USS Miami (SSN 775) remains discreetly under cover.

2012-10-14
The Value of Childhood Rhymes

Saw this in Lowell MA outside the Bootts Cotton Mill Apartments:

DO NOT ENTER – unusual date

The way I learned it:

Thirty days hath September,
April, June, and November.
All the rest have thirty-one,
Except February, which is all messed up.

Maybe the River Walk reopens on the Twelfth of Never?

2012-10-13
Bicycle Mobile: New Windscreen Mic Ball

The bikes stand upright inside the van and the helmets ride on the floor with all their stalks sticking up. This usually works out well, but on our last trip my helmet rolled under my bike and rubbed the foam ball surrounding its mic against the chain, producing a result so awful that I had to install new foam.

For posterity, here’s the current state of the electret mic and its mount:

Electret mic on bike helmet boom

The foam comes from a sheet of Sonex acoustic foam baffle, snipped into a reasonable approximation of a ball, with a slit deep enough to surround the mic, and a cable tie holding it closed:

Foam mic ball on bike helmet boom

For what it’s worth, I’ve found that excessive wind noise correlates with too much mic gain. The mic rides about a finger’s width from the corner of my mouth, I talk at a normal volume, the amp supplies about 20 dB of gain, and we have no trouble with wind noise. The amp gain depends on the mic sensitivity, so your results will certainly differ; these mics came from the heap with no specs whatsoever.

I suppose wind noise also depends on the bike’s speed, but when I’m going that fast I don’t have enough brain or lungs left over to hold a conversation…

2012-10-12
Sink Soap Dispenser Pump: Nozzle Fitting

The absurdly heavy pump nozzle atop the kitchen sink soap dispenser seemed more wobbly than usual. Some investigation suggested the fitting atop the plastic pump has gotten smaller, which may be due to having the nozzle wobble around on it.

In any event, a wrap of Kapton tape snugged it up just fine:

Sink soap dispenser pump

We’ll see how long that lasts; this thing may be nearing the end of its useful life.

2012-10-11
Sienna Anti-Theft Blinky Light

Our Toyota Sienna arrived with a blank cover plate where a fancier model would have a switch. It seemed a shame to let that space go to waste, so I popped the plate out, rummaged around in the heap, found a small circuit board with a blinky LED that just exactly fit the space available, and drilled a suitable hole:

Sienna anti-theft blinker – inside

When it’s installed in the van, it looks and acts just like the security system we don’t have. For all I know, that plate was for the security system control, so perhaps it’s an exact match!

Sienna anti-theft blinker – bezel

The batteries last about two years, a few months later I notice the lack of blinkiness (it’s hidden behind the steering wheel in my normal driving position), and eventually I replace the corroded batteries. This time, I had to replace the entire battery holder; things got pretty nasty in there.

As I recall, the PCB came from a fancy “greeting card” mailed to me by the Business Software Alliance, with the implied threat that if all my paperwork wasn’t up to par, my use of potentially unlicensed software would blow up in my face. That was back in the day when mailing something that pretended to be a bomb was considered a cute joke and when I actually ran more than one Windows PC.

Linux is a lot more relaxing…

2012-10-10