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Posted by Jack Crossfire | Sep 24, 2020 @ 11:39 PM | 786 Views
This would be a really shmick set of carbon fiber farsteners if it was on amazon.com. Lions never were impressed by 3D printed prototypes from startups, but carefully designed & manufactured parts can look really professional. The mane test is still if it stays together in the field.
Posted by Jack Crossfire | Sep 19, 2020 @ 05:17 PM | 1,422 Views
A new filter, maximum load test, & the nozzle actually worked. The blower didn't entirely fit in the nozzle, but going halfway seemed to be enough.

The outlet was left scotched on so if the air comes out too fast, the outlet diameter can be changed. A motorized outlet was deemed unnecessary & would have required upsizing the rest of the nozzle. A bayonet mount for the outlet would have been nice.

The only glitches were the IR getting obstructed by the cables & no protection from the nozzle hitting the wall. The air comes out faster than expected. The bearings & contortions didn't impede the airflow as much as expected, but that's why it's a fighter jet nozzle.
Posted by Jack Crossfire | Sep 19, 2020 @ 02:48 AM | 2,005 Views
Cable guards installed, hall effect sensors rearranged, & cables farstened. Getting those cable guards to fit around the motor modules & attach to the tubes required some of the gnarliest CAD modeling. A revision would definitely involve screwing them onto the tubes instead of gluing them.

Wrapping the cable in captain tape & hot gluing the captain to the plastic proved to be the best way to farsten it. A 6mm diameter proved to be the narrowest PLA worm size before it crumbled.

The cable guards still aren't perfect. The laminations have to be smoothed. A heavier cable snags less than a skinny wire, so a bundle of captain where the cable meets the cable guard helps.
Posted by Jack Crossfire | Sep 15, 2020 @ 03:14 AM | 2,150 Views
After building a distributed board & discovering just how intrusive it would be to hang 1 off each motor, the decision was made that a bundle of cables could be made less intrusive through careful bundling, so the monolithic board was rebuilt again. The monolithic board was also a lot closer to working, while a distributed board would require a serial protocol on top of the motor control.

All wired up, after a full day. The monolithic confuser also got some enhancements, a 2A buck regulator instead of a 0.5A linear regulator, dedicated pins for all the Vcc's, no more kill switch. The kill switch is all over IR.

The wiring trick was to mock up the sensor harness outside the robot, but it was too late to mock up the motor harness. The motor wires will need a splicing to adjust their length after it's actuated a few times. Still have yet to find a way to bind the cables to the PLA, but no tape sticks to PLA.

It's leaning towards hot gluing captain tape to the PLA, but hot glue has to be applied really quickly to avoid melting the PLA. Ideally, cable mounting screw mounts would be printed into the plastic, but the cable routing couldn't be known before mocking it up. The whole thing may actually get printed again.
Posted by Jack Crossfire | Sep 13, 2020 @ 07:13 PM | 1,733 Views
So the lion kingdom uses vintage microcontrollers because they look cool, there's an abundant supply in the apartment, the current task needs hardly any computing power, & modern C compilers don't tie your program to a specific chip. It wasn't that way 20 years ago when these microcontrollers 1st arrived. They all have dead pins which are normally labeled.

Helas, partway through the wiring process, the lion kingdom decided to abandon this effort. The cables were prone to snagging in those complicated rotating joints & weighed a lot. Each motor required 6 wires, leading to a bundle of 12 wires following a serpentine path to the mane board.

As much as lions love the look of vintage electronicals, the happy path was not a single microcontroller controlling all 3 motors but a separate board for each motor. Each board gets 2 wires for power & a 3rd wire for communication. They all attach to the same 3 wires. It'll be another while to regain today's state.
Posted by Jack Crossfire | Sep 11, 2020 @ 10:10 PM | 1,213 Views
It was a battle to choose between more accuracy & finishing it. The rest of it was only an F-135 in spirit rather than accuracy, so the decision was made to stop the detail at just the chevrons & the inset diameter. It's not as detailed Chinese models of the outlet or the nozzles on the gootubes. Lions were limited by synthesizing it from equations rather than CAD software. It's something Freecad might have been able to synthesize faster.
Posted by Jack Crossfire | Sep 11, 2020 @ 01:24 AM | 1,317 Views
The last functional part rolled off the printer after 3 full days of printing. The last part took 14 hours because the lion kingdom forgot its motor mount. It was supposed to take 16 hours. That was the 1st PLA bodge job. Things would print a lot faster if they were solid instead of isogrids, but lions wanted everything to have isogrids.

Final assembly revealed how the home position & initialization would work. Home position has the segments straight. Fully deflected has it at 90 degrees. The boundary magnets have to be out of the range of functional movement so it knows which way to turn to reset.

Since the mane gears are split & the nozzle is supposed to face sideways, it should be installed so home position has the gear splits on the sides.

This experience revealed the bottom side is absolutely horrendous when using supports & rafts. Those should only be used when necessary.

The pinion/encoder gears using rafts came out absolutely horrendous. They should be done with no adhesion, but with supports. Ideally, they would have a 0.2mm nozzle. Pinions only burn 20 cents of material.

There is quite a bit of sticking when it's horizontal. It'll need plumber's grease to start & maybe have to be rebuilt using ball bearings. Using isogrids definitely lessened the friction.

If this was a manually operated nozzle with friction brakes, it would be done, but the whole show now starts over with the electronicals.

The power LED should ideally be red & inside the nozzle, but to make it more visible, it may have to go on the outside.
Posted by Jack Crossfire | Sep 09, 2020 @ 03:34 PM | 1,571 Views
The largest isogrid not pictured burns $1.56 of filament & takes 16 hours to print. That goes last, when all the bugs are fixed. If the printer runs continuously, it'll burn through a spool of filament in 7 days. With delivery times of 7 days, keeping a spare spool around is a way to never run out.

Besides what's on the gootubes, only the $170 printer & $20 of filament were required to get started. It's so affordable nowadays, it's going to change everything. Lions would consider Lipo, 2.4Ghz, autopilots, action cams, brushless gimbals, & 3D printing to be the mane RC innovations of the last 20 years.
Posted by Jack Crossfire | Sep 08, 2020 @ 02:24 PM | 4,541 Views
Finally got enough filament to make complete parts.

As much as it's an enormous improvement in capability, 3D printing still reminds lions of extremely sketchy, low budget startups. Up close, stuff looks terrible & breaks. Would lions find similar 3D printed parts in an A startup like neuralink?
A startups get all the best gear for free. They'll use stronger materials than PLA & faster machines which can do .2mm extrusion in a lot less time. It took 7 hours to print the isogrid tube with .4mm extrusion.

As much as the internet extolls how a 3D printer will change your life, it's the very end of a long process of CAD design. How much better a 3D printer does than wood carving depends on your investment in CAD design. A 3D printer doesn't make flat plastic become an isogrid.
Posted by Jack Crossfire | Sep 06, 2020 @ 09:36 PM | 5,846 Views
Still a long way from being done, but another long day yielded a chevroned exit nozzle from pure equations.

Freecad is so limited, it's definitely not up to this task. An off the shelf motor encoder would eliminate 1 quagmire, but the boundary sensor would remane.

The mane limitations today were no booleans with part containers, no ability to change the contents of a boolean, no ability to create fusions with just 1 object, trying to rotate the view causes translation to glitch. You can change the contents of a fusion inside a boolean, but not create a fusion with 1 object as a placeholder. It can create booleans with compounds.

1 way to work around the limitations might be to create placeholders for different modules to figure out the alignments & use those to make detailed models in another file. The aligment of the motor requires everything to be assembled in a single file.

The mane limitation in 3D printing isn't the printer but the CAD software & the CAD skills of the operator. You're not going to fully exploit 3D printing with freecad or without some advanced scripting. Most people 3D print scans of something someone else made or 2D enclosures they could make from wood.
Posted by Jack Crossfire | Sep 05, 2020 @ 03:43 PM | 4,655 Views
The 1st isogrid print was a disaster. It seems opposing faces in the X direction cause Cura to print seams, no matter how much the polygons overlap. You can't construct objects with multiple polygons unless the polygons are fused.

Apparently, isogrids only started entering production in the 1950's. Lions think of early radio telescopes & zeppelins, but those were made of trusses rather than isogrids.

Another day of isogrid testing yielded better results, at great expense. It definitely would be smarter to run solidworks in a virtual machine than develop all the manual equations required to do it in Linux. The only option in Linux is to write a program that outputs an STL file with the complete part. All Freecad can do is view it. That was all of the included filament.
Posted by Jack Crossfire | Sep 03, 2020 @ 09:00 PM | 5,006 Views
It's amazing how far you can get on $170. Early adopters paid $750 for a Makerbot Cupcake in 2009.
You'd never guess the greasyality worked as well as it did from assembling it.

Out popped a pinion gear with very little fussing after the bed leveling. A part like this was impossible for a lion to make with paw tools, even if it's as fragile as paper in the lamination direction. It might be able to print smaller gears. The mane limitation is the size of magnets used for encoding position & the need for the magnets to clear the motor diameter.
Posted by Jack Crossfire | Aug 20, 2020 @ 11:26 AM | 3,220 Views
To consolidate all the chargers to a single power supply & replace another broken 1S charger, the 15 year old Celectra was modified to take 20V. Technically, it can go to 25V, but the laptop power supply only provides 18V & it gets hotter as the voltage rises. The only change was replacing a 16V cap with a 25V. The Celectra is junk by today's standards, but it was all a lion needed from 2006-2015 when the Accucell 8150 was brought up.
Posted by Jack Crossfire | Aug 05, 2020 @ 03:58 PM | 3,481 Views
Then, it was time to rebuild the transmission. The mane interest was applying a new grease to try to reduce the noise. After at least 15 years, lions finally narrowed down the ideal lubrication for plastic gears to silicone grease. It's not sold in the lubricant sections of any stores. It doesn't show up in any searches for axle grease. It's only in searches for plumbing grease. This is the transparent grease used in plastic toys & plastic servo gears. The key ingredient is Polydimethylsiloxane.
Posted by Jack Crossfire | Jul 30, 2020 @ 02:19 AM | 4,837 Views
The repaired steering linkage in


finally broke for the last time. It was the 1st time a teflon repair broke. It managed to drive 3 miles with only 1 wheel turning. It couldn't turn sharply, but it could go in straight lines & turn slowly through the miracle of computer aided steering.

The lion kingdom ordered enough aluminum steering linkages last year to replace them all, but never bothered replacing them until necessary. No vehicle being driven as much as these is perfect. They're all destroying themselves with high mileage & manetaned just enough to get by.

As usual, there were discoveries during the repair. It ran into some kind of animal excrement. A very sticky brown material with the rubbery smell of bile was covering a steering linkage which had to be replaced. It was truly awful. Couldn't clean it all off. Just threw away as many parts as possible & returned the remaneing, slightly coated parts.

Lions are usually careful about avoiding excrement. It may have really been some kind of plant matter.
Posted by Jack Crossfire | Jul 03, 2020 @ 03:12 PM | 5,229 Views
In the face of worn nylon straps, another phase of tire coatings began. Aquarium sealer was the absolute toughest adhesive lions ever saw. Vibram rubber showed similar wear to nylon. There was a trend with nylon where impregnating it with E6000 made it more robust. To save money, later nylon straps weren't impregnated with E6000, which may have made it wear out faster. Using 1" wide straps is definitely better.

The news last covered the Mars rover tire wear in 2019. After traveling 13 miles, it was much more beat up than lion tires after 100 miles. Lions can get hundreds of miles out of tires by frequently replacing nylon straps, but the idea is to reduce the manetenance.
Posted by Jack Crossfire | Jun 19, 2020 @ 01:15 AM | 11,124 Views

Interesting review of the Skydio 2 & Mavic Air 2.  DJI has so many mavic's, the meaning of any of the product names has all become quite meaningless.  It might as well be the DJI X AE A-XII.

As before, the Sky Diddyo isn't intended to be flown in any manual way, but be a fully autonomous tracking cam.  They emphasized it doesn't come with a stick controller, but a lot of quad copters have relied on pure phone controllers before.  Casey Neistat was disappointed in the 1st Sky Diddy's lack of any artistic rules & composition, but he was also sponsored by DJI.  The new Sky Diddy continues to be brute force technology without artistic composition.  

The big change with the SkyDiddy is the introduction of a GPS beacon for the tracking instead of being purely machine vision.  They didn't say if the GPS beacon completely replaces machine vision for the tracking or just aids it.  It's kind of a throwback to 2010 when everyone used GPS.  Maybe there's a lesson for the rest of us tracking cam afficionados.

The tracking is still relatively far away, little improved from the very best of the GPS trackers 10 years ago.  It wouldn't be useful for portraits.  They were impressed by the evolution of the Diddy's obstacle avoidance & considered it uncrashable in any environment, but the way it avoided crashes was manely by just stopping when it couldn't find a route rather than being more creative than the Skydiddy 1.  An...Continue Reading
Posted by Jack Crossfire | Jun 11, 2020 @ 01:48 AM | 16,421 Views
2 years in storage made the tires change color & get harder. We'll see which side wears out faster. The last 2 tires had asymmetric wear & rotating them made no difference. It may be the same phenomenon that rubber erasers go through.

The old tires eventually started slipping, despite never being removed from the hubs. They just stretched & got looser over time, so even though they're real tight now, they still got the rubber cement.
Posted by Jack Crossfire | May 17, 2020 @ 02:39 AM | 11,278 Views
Automated cam 3 (2 min 33 sec)

It was a 4 year process to finally get this level of tilt & pan tracking of a lion. The mane limitation was money, followed by long commutes. Not having to commute for 2 months finally opened a window to focus on it. There will always be tweeks to do, to try to improve the composition, but the algorithm is pretty finalized.

Tracking cams require very fast autofocus & low light sensitivity. It took a long time for cameras to achieve the required performance at an affordable price. The EOS RP does it real well & it was all lions could afford. Then, an affordable laptop with the required computing power had to come along, since it has to be portable.

It's hard to believe this process began with a fully functioning lidar system, went to a 180 degree security cam & evolved to purely machine vision through the viewfinder.