Robotic Arms

So I bought this arm from Hiwonder called the xArm. The arm itself is pretty good. Hardware is fine.

Robotic arms come in three general price points. The lowest is ~$40 and below, and they’re cool but garbage. Most of them have some interface and at least two joints + the gripper, but the servos are worthless and the metal is flimsy. Next up there’s a ~$100 to $200 batch of tolerable arms. The xArm is in this group; I think I paid about $200 for it. In this regime, most aspects are fine. There will generally be a few good points and a few drawbacks, but most things will be fine. Then there’s a deep trough of nothing until the $700+ arms. From there things go as expensive as you want.

The Hiwonder xArm is pretty typical for the middle group. The metal is well stamped, the pieces fit without filing or sanding, and the wires plug-in well. Some of the connectors are a little shoddy, and a few minor pieces fell apart. Still, it’s pretty good. I’m going over it with Loctite, and my machine shop made a new stand. That’s probably not something most people have access to, but this is a work piece. Physically, it’s fine or good.

The downside is the software. Everything is locked behind this odd digital mask. I can’t send PWMs to the servos or get position info out without doing this weird, proprietary dance in encoded hex. Hiwonder really wants me to use their software, but their software isn’t that good. I can’t get kHz+ position information at all, they don’t have good scripting or export tools, I can’t use other software or hardware for control, and the entire process is kludgy. They don’t have any useful tools.

If I have to use your protocol, why don’t you make an opensource translator? If you want me to use your software, why can’t I export position data as quickly as it gets written? Why are you limiting things?

One of the senior engineers keep telling me to ditch this thing, but short of jumping up to the >$700 regime, there isn’t much.

What’s weird is that the arm would be much better if it wasn’t hobbled. Hiwonder, you have a good arm. Stop making it worse.

Twilight in Heaven: Chapter 36

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Chapter 36

Amber Melis was the only tower with a star on top of it.

When I had worked here, the argument over moving the stars of the Mask from the mountain tops around to the spires of the seven towers had more or less ended. I remember first hearing about the issue and obviously supporting moving the stars to the towers. It seemed a brilliant idea, full of verve and light. This was before I’d spent a few months in a moldly, dark cubicle farm that smelled of feet. I then understood the issue, and the issue was that whatever Fate did, it did poorly, ineffectually, and in the dumbest possible way.

I’d none the less been drawn to the star of Amber Melis by the compulsion of a bonfire of unused destinies atop a seven-sided tower on the firmaments of the sky. It was bonkers neat. I’d spent a lot of time wandering around the maintenance corridors, back rooms, and unused stairways, and since I hadn’t gotten in anyone’s way, no one had objected. I headed there now.

The tower itself had a lovely foyer. Made of sandstone with quartz veins, the foyer had vaulted ceilings and internal windows from the atrium to second, third, and fourth floor offices. Those quartz veins ran throughout the building, carrying light from the star above to every room. The floor glittered underfoot. Speckles of sand caught in the quartz caught light from all sides, and they twinkled as one walked over.

Head down, eyes on the floor, posture slouched, I walked, glanced around, and made for the stairway. I wanted to stop and look around, but some helpful docent might try to give me directions. My badge name, Hroth Urmain, was probably the best fit of the stack, but I didn’t look like a nord. It was better than Sslass Sssa. Then someone might ask where my other arms were.

In the stairwell a couple of young women passed me doing laps for exercise, so I gave them an office smile and kept going. They looked annoyed they had to go around, and I made sure to walk extra slowly so they put some distance between us. By the time I came to the top floor, I hadn’t seen anyone in minutes and the echoes of clicky-heels had faded.

The top floor door required a hand-pass. The doorknob was true amber polished to shine, and the silhouette of a hand was carved into the stone. Someone authorized to be here was supposed to open it by holding it just right, and the spells on the knob would recognize the hand. I was no so authorized.

Up a floor a door was locked and barred with mundane bolts and locks. Someone had painted ‘Roof Access’ on the door with a stencil. I glanced around again, still saw no one, and went to work on the bolts and locks. They were doable.

The door lead to a pathway beneath an inferno.

Overhead the star burned. A mesh ceiling separated me from the flames, but fires roared. Hearing was impossible. Light-pipes for the entire building made up the floor, each one feeding a vein of quartz that would illuminate the halls. Huge rolls of fate’s threads as big as shipping hawsers stood in piles. Their upper ends fed the flames, and as the tips burned, they stretched. The coils slowly unwrapped, feeding themselves into the blaze above.

The wind was a hurricane. Channels ran through the floor, channels bigger than the Hemlin cousins’s house, that brought air from outside the tower to the roots of the fire atop it. The wind pulled my clothing and hair, made my cuffs and collar rise, and my shirt flap. I had to tuck everything in tightly to avoid inflating like a blimp. Everything up here tried to go higher, from the slithering cables that moved like snakes feeding themselves to the burning star to the rushing air. Some sparks ran in loops after being shot wide out the top, caught in the air intakes, and lifted into the blaze again.

I shut the stairway door behind me but did not lock it.

I hopped off the catwalk to the ground and climbed onto a cable pile. If I got stuck in this thing, I could get carried with it as heat pulled it into the blaze, so I was flat out paranoid. Yet for all the risk of imminent death, and the roar of starfire overhead and the beating heat reminded me that death didn’t so much lurk nearby as scream its presence, this part of the entrance excited me. I climbed through the ropes until I found a long, cast-iron pipe that lead down through the roof below. The lips of the pipe had been worn smooth by millenia of cables, and the opening was wide enough that the cable never got kinked. I climbed down like a ladder.

And then I was through, into the hidden world of Amber Melis’s secret pathways and out of the normal world of Fate’s routine operations.

A vertical shaft rose from darkness below to a number of openings above. Through each of them ran one of Fate’s cables, a thousand unmade choices and events that never happened, wrapped together into a thick cord as big around as a tree trunk. Climbing those cords gave me hints of visions, illusions of movement in the corners of my eyes, and scraps of music underneath the hum in my ears. I almost heard words never said. I almost saw things that didn’t exist. People who work in the Loom itself learn to read the threads by fingertip-pressure, but those are well constructed fates feeding Destiny. Those things happened. These threads didn’t, and I didn’t have the practice to read them anyway.

I’d always wondered what would have happened if I had. Could I figure out who wouldn’t win the Great Games next year and bet against them? I don’t think that was possible because these threads had already not happened. But could I figure out who hadn’t won their games by cheating and bet against them? I could drop an anonymous tip to the Triumph Commission. I think that would work.

But I could listen for clockwork spiders, so I did. They crawled around down here. Not often, but a few times I’d met them. The spiders weren’t that scary if they didn’t surprise you. They’re weird, mechanical beasts of gears and springs, their footsteps click, and they seem to pay no attention to up or down. Most of them are about the size of large mice. The Loom spiders are the size of houses, and they’re the ones that scare people. The ones around here aren’t that bad.

They’re not bad if you know they’re there. If I got startled by a moderately big one, maybe the size of a house cat, I’d probably just die on the spot. I’d do it deliberately, maybe via exploding, just to be sure.

But I saw none, neither big nor small. I bowed my head and said, “Pattern Spiders, I, Kog, come among the back passages of Amber Melis. Please do not startle me. I will do no harm and intend only to pass by. Thank you.”

They didn’t reply, but they didn’t pop out of hidden spaces either. They’ll generally leave you alone if you leave them alone.

I climbed off the cable onto a steel girder that ringed the shaft. It had a little door on one side that lead to a long, narrow hallway with speckled stardust in the ceiling. I tapped a few times to let anything inside know I was coming before hurrying through.

With all the unused fate moving through Amber Mellis, things had a tendency to get lost. Things like rooms and stairs and doors. No one goes through them, and the fate of a door to let someone through might get burned up in the star above. Yet the original purpose of Destiny had been to tie all things together, and Fate handled Destiny. Little fate was the stuff of Destiny. (Little destiny is the way everything in your life is going to get tied together eventually, but there’s no guarantee, assurance, or intent to make it comprehensible to you. Even if you did get an explanation, it would be written by an intern, so it would be badly mispelled, incomplete, and possibly illegible with coffee stains.) So at Fate things got lost in the way no one knew where they were, but they didn’t get lost in that they went away. They were still right there.

I moseyed down a forgotten hallway with old carpets, slightly yellowed white walls, and drop ceilings full of missing tiles where cables of unused destiny wound slowly across the floor. Piles of clutter lay here and there, eventually getting caught in the cables to be taken up to the star and incinerated. I checked old stationery and business cards. Judicial Director Priam’s office had to be around here somewhere, and eveyone loses a sheet of paper with their name on it eventually.

Priam had.

His office was on the second-highest floor in the middle of a side. He didn’t have a corner office, but he did have a great window. His forgotten door was a dumbwaiter from the often lamented before-time when Fate served drinks in-office. A weathered slip of paper that looked like a laundry tag was stuck in the dumbwaiter hatch.

I checked the door. It looked clean. I put my ear to it and heard voices.

Hoarfast was speaking softly to someone on just the other side. He said, “Just stand in the doorway and watch. If anyone comes in, just act dumb. I’m almost done.”

“But what if-” said a voice I couldn’t place.

“No what-ifs. Just wait outside with those papers like you’re ready to deliver something. Go.”

“But what if-”

“Go! Go now,” he said, quietly and authoritatively.

The other voice whispered something but retreated. Another door opened and closed.

I craned my head around the dumbwaiter hatch, looking through the little cracks.

A desk have been moved directly in front of this area, and a figure was leaned over it, reading something. The figure was a big man who cast a long shadow. He was close enough that if I reached through the doorway, I could touch him.

I did. I braced one hand on the doorframe, set my hips, and threw a huge, wide swing like I was showing off on a heavybag. My fist shattered forgotten wood, knocked papers sideways, and caught Hoarfast dead in the sternum with my whole weight in the swing.

I shattered the little door the rest of the way as I dove through, caught Hoarfast as he crumpled, and pinned his head against the floor with my left hand as I dropped overhead punches with my right. Each hit rattled his brain in his skull.

Osret of Hemlin shoved the door open, a folder in his arms, and demanded, “What are you doing–” before he and I saw each other.

Osret whispered, “Death on you.”

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