Mastodawn

Sp4rkler 3rickson

@sp4rkler3rickson

63 Followers

63 Following

388 Posts

United Methodist; Asexual; INFP; Complex neurodivergent 
Digital artist; aspiring YouTuber

 Primary Characters: Spark E. - anthro border collie, adopted little brother of Lam E. (representing my ego) 
Lam E. - anthro sheep, adopted older sister of Spark E. (representing my superego) 
Tom E. - feral demon cat (representing my intrusive thoughts, inner doubt, and self-deprecation)

I sometimes block prompters. #SayNoToAIArt

My Other Socials:

https://linktr.ee/sp4rkler3rickson

Sp4rkler 3rickson 2h ago

It occurs to me that D*n*ld Tr*mp might just be three kobolds in a trenchcoat.

It also occurs to me that I'm most likely not the first person to make that joke.

#3koboldsinatrenchcoat #threekoboldsinatrenchcoat #theAbominableOrange

Sp4rkler 3rickson 2h ago

Discord really lays on the insults when you try to upload an image file that's too large...

Sp4rkler 3rickson 3h ago

I woke Critter up to take a picture of her to send to my mother, who is currently out of town.

#kitty #cat #kittycat #cutekitty #cutecat #feline #cute

Sp4rkler 3rickson 1d ago

@WriterOfMinds I've already tipped over a trashcan.... sorry.🥺🐾

Sp4rkler 3rickson 1d ago

Dear YouTube,

You have a very bad track record for recommending videos I want to see.

And when you ask me if I would like any of the videos you queue up to improve my recommended page, I have no way of knowing for sure whether I will like a video until I click it...

...And in doing so, I know you will take that as an endorsement for my recommended page.

Screw your algorithm! Give us filters we can program ourselves! Put the power of recommendation back in our hands!

Very mad,
Sp4rk 3.

Sp4rkler 3rickson 1d ago

Critter the cat, Wednesday, June 18, 2025.

#cat #kitty #meow #cute #cute at #cutekitty

Sp4rkler 3rickson 2d ago

Storyboard excerpt from a skit I'm planning out, even though I haven't made the "I'm a Dogwood Now" skit into a proper video.

Proud to say I freehanded three layers of linework, placed the fill colors, cel-shaded the foreground elements, and airbrushed the outlines in about an hour.

#furryart #furry #anthroanimalart #anthrosheep #driving #storyboard

Sp4rkler 3rickson 3d ago

Followup question: does anyone think I should add Mollie the cat to that prominently empty space above Lam E.'s right shoulder?

Mollie is pictured here:

Sp4rkler 3rickson 3d ago

"Surrounded by Jealous Dogs"

I considered having Mollie, my gray and black tabby, climbing on the chair behind Lam E.'s right shoulder, but decided it would be funnier if it was all dogs showing jealousy for the chihuahua in her lap.

#furry #furryart #anthrodog #anthrowolf #anthrosheep #humor

Sp4rkler 3rickson 4d ago

No art today. Posting the #kitty

I should have some art to post by tomorrow.

#cat #kittycat #cute #cutekitty #cutecat #cutekittycat #meow #adorable

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Ken Shirriff 5d ago

When landing on the Moon, the astronauts watched an instrument called the FDAI that showed the spacecraft's orientation. The ball inside the Flight Director/Attitude Indicator rotated in three axes as the Lunar Module rotated. Let's look inside and see how it works. 1/N

Ken Shirriff 5d ago

How does the FDAI's ball rotate on three axes without coming loose? The trick is that the ball mechanism rotates on two axes, but is covered by a hollow shell that rotates on the third (yaw) axis. The motors for pitch and yaw axes are inside the ball, while the roll motor is outside. 2/N

Ken Shirriff 5d ago

Hopefully this orange will clarify how the FDAI's mechanism works :-). Rotating my hand would rotate the ball around the roll axis (red). The ball can pivot forward or back for the pitch axis (yellow). If you imagine a hollow hemisphere sitting on top, spinning the hemisphere is the yaw axis (green). 3/N

Ken Shirriff 5d ago

Removing the hollow hemispheres from the ball shows the complicated mechanism inside the ball, including the pitch and yaw motors. The pitch motor causes the entire mechanism to rotate, while the yaw motor spins the hemispheres.

Ken Shirriff 5d ago

Here's a video of the FDAI in motion. I removed the hemispheres so you can see what happens inside the ball.

Ken Shirriff 5d ago

Why don't the wires get tangled when the ball spins? There are two slip rings that provide electrical contact as the ball rotates around the roll and pitch axes. This closeup shows how stationary brushes contact metal rings on the rotating shaft, allowing 23 connections.

Ken Shirriff 5d ago

The FDAI instrument that we examined was built in 1968, before the Moon landing, and was then repurposed for a Space Shuttle simulator. The red arrow in this photo shows an FDAI in a Shuttle simulator. When the Shuttle (and simulators) moved to digital screens, the old instruments were scrapped.

Ken Shirriff 5d ago

For more details on the FDAI, including the servo loops and electronic amplifiers (powered by germanium transistors), see my blog post: https://www.righto.com/2025/06/inside-apollo-fdai.html

Inside the Apollo "8-Ball" FDAI (Flight Director / Attitude Indicator)

During the Apollo flights to the Moon, the astronauts observed the spacecraft's orientation on a special instrument called the FDAI (Flight ...

Ken Shirriff 5d ago

Credits: thanks to Richard for providing the FDAI. I worked on this with @CuriousMarc, @tubetime, and Mike Stewart.
Simulator photo from "Introduction to Shuttle Mission Simulation": https://ia804505.us.archive.org/8/items/intro-to-sms/intro%20to%20sms.pdf#page=22

rogerggbr 5d ago

@kenshirriff @CuriousMarc @tubetime brilliant images and great explanation, thanks.

@kenshirriff I want someone to design one I could build that doesn't gimble lock. That would be so cool.

F4GRX SÃ©bastien 5d ago

@kenshirriff this slip ring is insane.

Andrew Zonenberg 5d ago

@f4grx @kenshirriff 23 channel slip ring, wow...

@f4grx @kenshirriff *Picture of a seraphic host, but instead of eyes it is covered in ears. It is wearing headphones specifically made for its p̶h̶y̶s̶i̶o̶l̶o̶g̶y̶ mythology(?), and plugging this exact headphone plug into its mp3 player.*

Marsh Ray 5d ago

@kenshirriff The brushes seem to disappear into the rings?
Is there another angle?

@marshray @kenshirriff
Looks like the insulating material protrudes out beyond the diameter of the rings and obscures the view of the wires. Presumably to stop any axial load or vibration causing the wires to contact the wrong ring.

Ken Shirriff 5d ago

@geoffl @marshray Yes, I think you're right that the insulators protrude, forcing the wires into channels. Here's a view from the other side.

Marsh Ray 5d ago

@kenshirriff @geoffl It looks like there’s a V-channel in the rings, thanks!

Philip Crawley 5d ago

@kenshirriff Similar arrangement to the slip-rings in the rotating head-drums of broadcast VTRs - although the signals from the heads left the drum via rotating transformers control signals and power (esp. the high voltage variable signals used to deflect the dynamic tracking heads) entered via slip-rings.

@kenshirriff damn, it's got a whole hellraiser cube hiding in there.

Ben Brockert 4d ago

@kenshirriff I imagine that if you see it do that while operational, you will not be landing on the moon that day.

What a cool mechanism! I wonder if somewhere there was an engineer arguing for a fourth axis to avoid gimbal lock.

Ari [APz] Sovijärvi 5d ago

@kenshirriff Incredible by today's standards to see a hand drawn PCB in space stuff.

Tushar Chauhan 5d ago

@kenshirriff This is beyond cool. Looking forward to this thread !

Vassil Nikolov 4d ago

Thank you.
An impressive presentation of an impressive device.

Would you happen to know what was the effort to develop it (design and implement)?
How many people for how long?

Ken Shirriff 4d ago

@vnikolov I don't know how much effort went into the design. It was incremental improvements dating back to the 1950s. A detailed history is here: https://www.glenswanson.space/uploads/1/2/5/7/125738648/on_course_to_tomorrow.pdf#page=3