In a comfortably cobwebby place there hangs a cork-board. And pinned to it, amidst a camp of construction-paper bats, Count Chocula’s signed mini-poster, and a drawing of the Mach 5, is a crumpled piece of notebook paper. Smudged pencil scribblings cover both sides in an apparently continuous scrawl, but look closer and you’ll see it’s a list; a catalog of sorts.

It’s late August, Labor Day is coming, and I’m staring at a project list that has burst out the garage door and plowed through the overgrown hedge at the end of the driveway. As I stand here watching, it’s roughing up a rabbit in the neighbor’s yard.

Still, if I’ve learned anything from Kristy McNichol and a herd of ABC After School Specials, it’s that you have to stand up to a bully. Don’t let him spoil your fun because the only real power he has over you is what you give him. Oh, and never ever let the ranger dart the baby deer you’re nursing back to health.

In other words, sometimes you’ve just gotta chuck the plan and follow your nose. To illustrate the point, I present a note we received this morning.

Our friend Wlbrid writes, “I was looking at your SpookyFire flashing LED project and I was wondering, wouldn’t all the LEDs flash simultaneously (instead of being out of synch / semi-random) because they will all be turned on at the same time?”

What follows is an excellent example of dropping everything, tearing across the room, yelling “squirrel!”, and jumping out the window.

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Dear Wlbrid,

Excellent question! A flashing LED contains a very tiny integrated circuit called a multivibrator. A multivibrator circuit is used in a variety of applications that require switching between two states, and there are three distinct types: astable, monostable, and bistable.

The astable multivibrator is stable in neither state (states are “on” and “off”) so it oscillates back and forth continuously. The period of oscillation (frequency of change) is determined by a built-in capacitor/resistor network. A monostable multivibrator, or “one-shot”, is only stable in one state for a period of time. After it is triggered, it will eventually return to its stable state, which makes it really handy as a programmable timing circuit. A bistable multivibrator, or “flip-flop” is equally stable in both states. When it’s triggered, it will flip states and stay there.

All of this can be accomplished in the astable circuit with a pair of transistors, two capacitors, and four resistors -discrete components that only the very very nerdy, old-style Radio Shack types (cough) have squirreled away in their garages and shops in neat rows of little plastic bins.

The first vacuum tube multivibrator circuit was completed in 1919 by radio and electronics pioneer William H. Eccles and his trusty side-kick Frank Jordan.¹ Jordan had a side-business in thermogalvanometers², but… well, he got really into the 20s, and no one ever saw him again.

But a flip-flop isn’t what’s inside a flashing LED, so once again Mr. Jordan is relegated to the mists of obscurity. Your garden variety Spookyfire Blob flashing LED has built into it a tiny little astable multivibrator circuit. The thing about these guys is that whether they’re constructed out of massive discrete components or microscopic little doo-hickeys, they’re not very accurate. I mentioned earlier that the duty cycle can be changed by varying the resistance and/or capacitance values in the circuit. If these components vary in the least bit from one circuit to another (or one LED to another), their frequency relative to one another will be slightly different.

Since these components (both big and little) often have 5%, 10%, and even 20% tolerances (the % difference between the stated and actual value of a component), you now have your answer.

Why don’t all the LEDs in a Spookyfire Blob just blink on and off together? Blame F.W. Jordan.

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1 wikipedia – multivibrators
2 wikipedia – F.W. Jordan

Category: Stuff   Tags: flashing leds, leds, spookyfire blob, squirrel

It’s your old pal Spook here (Yep, I’m still around). I figured we’d take a short break to give the two readers that I still have some relief from the dull ache that has become the Blue Aliens saga.

Lightning struck a utility pole last night and plunged Snug Harbor into the 1700’s. It was right before sunset and the weather was still unsettled after a nice little thunderstorm.

Fingers of purple lightning chased each other across the sky, playing hide and seek among the low scudding clouds. Dark windows all up and down the street looked startled, black but for the occasional bobbing flicker of a flashlight or candle within.

Clumps of saturated leaves, tugged by a mischievous breeze at just the right moment, dumped buckets of cold rainwater on unsuspecting passersby. Laughter echoed across the hollow as neighbors stepped out onto front porches to smell the fresh, wet, wonderful air and greet one another like relatives at a family reunion.

Hurricane lamps were brought down from attics, hastily dusted off, and fitted with beeswax candles. The sharp acrid smell of burning hair lasted for just a moment while the cobwebs burned off.

The gathering gloom of night strode confidently into the open to fill every space inky black, but it was frustrated by these small glowing pockets of orange warmth. Elated shadows danced up walls, frolicked on ceilings, and played peek-a-boo from the window curtains. Long ignored, these creatures of imagination were suddenly, gloriously, hilariously brought back to life again.

Sitting at my desk, I breathed in the clean night air through the open window. The dogs were safely tucked in and the cat sat staring at me in her magisterial fashion, perched at the very edge of the desk like cats do. I opened a spiral notebook of crisp paper, slid one of the many candles a little closer, and picked up my Ticonderoga pencil.

It was time to write a ghost story.

Category: Halloween, Stuff   Tags: candles, darkness, ghost story, hurricane lamp, power outage, storm

It’s the first really hot day of summer, but still early enough in the season that you haven’t smelled anyone light up a smoke bomb yet unless they’ve been saving it all this time, and that almost never happens. The Fourth of July is weeks away, sidewalks still tickle tender feet just starting to put on their seasonal skin, and summer is fresh like a brand new basketball.

In one backyard, sunlight filters through a huge green umbrella of a tree to cascade down and play over the ground in hundreds of gyrating spotlights. Two small figures huddle over something, sitting like a couple of frogs with knees up past their ears and backsides not quite touching their pile of sand. Dusty and growing warmer at the terminator line between green shadow and full sunlight, toy trucks and construction equipment fill the sandbox, but everything is motionless as if some big project has just ground to a halt. The two boys look as if they have unearthed a treasure.

White sunlight slowly creeps across the sandbox, pushing back the dazzling lights and turning the little dunes into a vast desert wasteland. A wavering chant rides the wind up over the garage.

“Mum-my curse is locked in-side,
If you’re smart you’ll run-and-hide,
If you o-pen up-the-door,
Mum-my curse is free-once-more!”

The boys jump back, startled, then flop down into the sand roaring with laughter. At the top of the sand pile is a plastic model crypt, its door flung open by a little plastic mummy. A ratcheting sound makes the mummy vibrate, its arms poking through the opening.

Soon the noise slows down and stops. The boys poke the little mummy back into its tomb and close the door. As they slowly wind up the toy, grinning madly, they begin their chant again, “Mum-my curse is locked in-side–”

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I don’t remember exactly where that little mummy crypt came from; we might have swiped it from some board game. Saddest of all, I can’t recall my friend’s name. But the game we played was hilarious for a pair of 10 year old boys. And I jumped every time that door popped open.

Category: Halloween, Stuff   Tags: childhood games, mummy, mummy's curse

Memorial Day in Snug Harbor.

Smoky aromas drift across backyards mingling barbecued chicken and citronella in a fragrance that is uniquely American. Families gather to remember. Some groups are solemn, quiet, and tearful. Others are loud, raucous affairs with music and storytelling that brings a special cauterizing laughter that stings.

This holiday weekend, normally reserved to honor our military dead, feels more solemn for us since we lost Ransom, our Golden Retriever nephew, last month.

Hug your dog, throw the tennis ball, run, laugh, make the time count. And let him have a hot dog. That’s like the Fourth of July and Christmas all thrown together for a dog.

Remembering Ransom – Gallery of a great Golden

Category: Stuff   Tags: rainbow bridge, remembering ransom