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Expo70
Nov 15, 2021

Can't talk now, doing
Hot Girl Stuff
Sure, so the goal is to have 4-axis: One linear, three twist like so:

https://i.imgur.com/Ba8uAsb.mp4
There would be two units mirrored, mounted to the arms of a chair: One left side, one right

Length Linear axis

  • Linear requires force feedback to move to a software defined "home position"
  • Linear requires ability to simulate a detent with mechanical resistance
  • Linear requires some ability to know how much force (nothing exact or precise, just proportionate to resistance) is being applied to it, and to "give up" if too much is given

Twist axis
  • Limited Twist axis (x3, 30 degrees)
  • Twist axis requires force feedback which can return to a home position (eg, "middle")
  • This "middle" needs to be varied in some way (intentional drift, feedback, or moving the middle to an endpoint as explained later)
  • There needs to be mechanical resistance involved
  • Twist requires some ability to know how much force (nothing exact or precise, just proportionate to resistance) is being applied to it, and to "give up" if too much is given

What are you looking to solve/What do I want to ask about?
The twisting axis don't need to be particularly compact or match the preliminary above at all -- they just need to be fairly responsive and somewhat accurate.
The linear axis, I'd like to not be too much taller than say, a fist, but I'm fine with it being quite wide, or using clever tricks to conceal the bulk of it.


For now I'd like to focus on the linear axis and work with ShameBoy towards producing a prototype, then do successive versions where features are added later like the twist, and then the grip design toward the end.

While I'm sure Shameboy is really really skilled both in electronics and as a programmer:

I'm mainly someone who writes tolerable code, reverse-engineers old games tolerably, and does some human factors stuff as a hobby so I'm not particularly knowledgeable about electronics.

At the cost of sounding a bit egotistical, I did think Steel Batallion was a bit smalltime when I took it apart: Its all smoke, mirrors and vibes and while very lovely, I want to build something more tangible.

I have consulted /r/hotasdiy and I did get into Arduino programming, but the most advanced things I've done are read axis on thumbsticks and buttons, or flash lights on and off a few times.

Something like servos or an alternative to servos would really be great.

I have never ever built a force-feedback device before, and have been intimidated by the wiring diagrams of arduino keyboard projects due to some color-blindness and problems with visual processing disorders reading text.


Usecase of the linear axis:
I'm simulating a vehicle in Unreal Engine with aerodynamics, gravity, torque, etc, etc and a flight controller.

This is all up and running, though its not in a state where I feel comfortable presenting a demo yet.

1) Flight controller has some simple competing behaviours (collision avoidance, stall caution, pitch-rate limiting, control surface driving etc)

2) Flight Controller likes to run as a self-stabilizing feedback loop -- for example, maintaining a relative position or orientation to a moving object.

Left side (translational controller):

If I say, tag a moving object in my simulation and pull the left linear axis back, the vehicle will attempt to station-keep relative to that object.
If I push forward, the Flight Controller might complain about a collision risk. Pushing the left linear throttle forward gives me more command over the vehicle, and gives less command to the flight controller's decision. As risk increases, it will mechanically resist the action more, giving me a sense of the time to intercept, or the risk present.

Right side (orientation controller):
If I attempt to feed in an orientation command, the system will naturally be limited by what the flight controller thinks is a sensible maximum which won't rip the wings off, or induce stall. As I feed the linear axis forwards, the system is less concerned with stall risk. At lower speeds, I could apply a very heavy torque with a burst of thrust from the simulated vehicle in rate command, then yank the right linear axis back: The system will try to neutralize the rate. If I zero the right linear axis, the system will instead attempt to match a coordinate orientation, akin to how Warthunder works.

If when ground contact is available, I push the right linear axis to 100% forward, I can make the automatic balancing behaviour of the vehicle deliberately fail and go prone -- essentially, re-orienting the pelvis of the vehicle using the twist axis.

In practice, this actually works beautifully but I am limited by what I can "feel out" from the system: Audio warnings are helpful, as is vibration in a controller or joystick, but I need more axis than a standard joystick really offers to maximize the agility of this fictional vehicle.

Example of twist behaviour
In many common excavation vehicles, it is common that if a stick or input device is pushed to the maximum along a given twist axis, the rate locks and the vehicle performs an automatic action. In this case, the desire is a sort of persistent position, where if an axis is twisted to its limit, the system will "pretend latch" with servo-motors or some other feedback system as such that resistance doesn't have to be maintained in this direction. Having experimented with modified controllers for 6dof conditions with other people's systems I quickly realized having to physically hold a twist throttle in a direction results in much faster fatigue, and so a kind of "in software latch" would solve these kinds of common input control behaviours.

Conclusion:
Right now the simulation is limited to what fits on a common twin stick gamepad. Rolling and balance toggling is stick buttons. Right trigger operates the main booster. Left stick tilts the main booster in screenspace. Right stick re-orients a camera or cockpit view. Left trigger balances the pelvis in the last direction left stick was fully pushed in. A fast press of left trigger while left stick is active commands a high pulse of thrust. A fast press of left trigger while left stick is neutral attempts to station-keep and marks an object for lock, akin to z-targetting. The simulated vehicle works well for aerodynamic flight, VTOL manoeuvring, microgravity conditions, climbing, affordance across complex surfaces and in water and is pleasing to use in 6dof conditions with a complex aligner and balancer system which ensures the vehicle remains upright, or is able to compensate for stability and affordance failures during operation in ways which are pleasing and fun.

While this works really really well, I feel the simulation is capable of quite a lot more, and the input devices I'm using can't really get more and I'd like to research these aspects of the simulated vehicle more.

What even is this?
I know this sounds a bit silly but on and off over the last maybe 20 years or so I've been studying declassified vehicle manuals and vehicle design, and for fun a few years ago I decided to write a simulator which takes into account some simulated forces and decided to try designing a responsive control stack, able to select and target and lead objects at high speed and perform complex 3D manoeuvres in all kinds of environment. It included a pelvis simulation with balancing, affordance/grip and complex surface alignment as well as colinear aerodynamics (including wind), a simple water system for the ocean and gravity. I would put the simulation complexity somewhere on the same level as something like https://ysflight.org/, but for the express purpose of figuring out "how the hell a giant robot would work".

The software side is almost entirely solved a this point and it feels pretty good to operate -- whether flying aerodynamically as a lifting body, running, skating or even sky-diving. About the only environment I haven't really solved is orbital, because orbital mechanics make my head spin.

I'm not so absurd as to go to the length of doing huge complex 6th order polynomials.

I'm pretty much 100% convinced that if I can meet this functionality in the inceptor design and then more conventional design solutions on the grips at a later date, I can "solve this problem" and put 20 years of thinking to rest.

I have more writing on the subject which I need to take out of a dumb reddit post I wrote I think a year ago and format for Tumblr if anybody hates themselves/loves giant robots enough to read this stuff which I can put together if anybody is interested.

tl;dr:

robots are cool also sorry for wall of text i'm kinda enthusiastic

Expo70 fucked around with this message at 23:32 on Jan 19, 2024

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ANIME AKBAR
Jan 25, 2007

afu~
Thanks to everyone who made suggestions on the connector. Yeah if any one of those requirements is eliminated then it becomes solvable. Alas.

It's for a panel-mount LED like this one. There are certainly other ways to put a nice looking indicator on a control panel, but most would involve a tiny PCB which is ~*too complex*~. So the leading option now is to use small FASTON terminals for each of the three wires, lol.

babyeatingpsychopath
Oct 28, 2000
Forum Veteran


ANIME AKBAR posted:

Thanks to everyone who made suggestions on the connector. Yeah if any one of those requirements is eliminated then it becomes solvable. Alas.

It's for a panel-mount LED like this one. There are certainly other ways to put a nice looking indicator on a control panel, but most would involve a tiny PCB which is ~*too complex*~. So the leading option now is to use small FASTON terminals for each of the three wires, lol.

Why would a 2x2 dupont connector not work? Or even individual dupont connectors that you plug in individually? What's the driving factor for "retention" on a panel-mount LED?

This now feels very much like a case of "the solution you're looking for isn't the actual problem you're trying to solve."

ryanrs
Jul 12, 2011

RGB LED on the PCB, and a light pipe to the front panel?

Is there a product like a flexible 'light hose'? Seems like a tube of the right kind of plastic would work. Like an optical fiber, but giant so you don't have to care much about coupling and can just tack it to the PCB with UV adhesive or whatever. I feel like this should exist.

e: eh maybe just go with the fastons but hate it

ryanrs fucked around with this message at 19:19 on Jan 20, 2024

PDP-1
Oct 12, 2004

It's a beautiful day in the neighborhood.

ryanrs posted:

Is there a product like a flexible 'light hose'? Seems like a tube of the right kind of plastic would work. Like an optical fiber, but giant so you don't have to care much about coupling and can just tack it to the PCB with UV adhesive or whatever. I feel like this should exist.

Google for 'flexible light pipe'. Bivar is one manufacturer.

I have used them to provide a front panel indicator that is isolated from the high voltage thing doing the indicating. The left side of the image below is the panel side, the right side is a 90 degree reflector with feet that snap into holes in your PCB and it has an interior pocket for a SMT LED to go into.

It works ok, the frosted diffuser on the output end scatters into a wide cone so you have to run the LED a bit brighter than normal to get a good output.

e: The flexible light pipe part friction fits into the periscope so you can insert/remove the PCB without taking apart the front panel.



PDP-1 fucked around with this message at 20:47 on Jan 20, 2024

Bad Munki
Nov 4, 2008

We're all mad here.


Looking for some help in trying to find a through-hole replacement for this SMBJ7.0A zener diode but I'm not sure which specs are actually critical. It'd be replacing the protection diode in the basic application provided by the data sheet for my power supply, see page 3. Second line in the table below that, the one with the 330uF cap.

Yeah, I can do it surface-mount as-is, but for various reasons, I've been changing my design to be through-hole and I figure why have one single remaining surface mount part. Otherwise, if the experts here think I should just leave it alone and squelch this mild desire for absolute consistency, I'm willing to hear that too.

ante
Apr 9, 2005

SUNSHINE AND RAINBOWS
It's this one:

https://www.digikey.ca/en/products/detail/littelfuse-inc/SA7-0A/557135


It's kinda funny that the specs are slightly worse. The difference is the 50A vs 42A peak pulse, but that's not really that important. If you're actually squelching 42A - 50A on the regular, your design is already fuuuuuucked

Bad Munki
Nov 4, 2008

We're all mad here.


Thank you!

kid sinister
Nov 16, 2002

PDP-1 posted:

Google for 'flexible light pipe'.

Interesting. I assume these are just cheap set length fiber optics?

PDP-1
Oct 12, 2004

It's a beautiful day in the neighborhood.

kid sinister posted:

Interesting. I assume these are just cheap set length fiber optics?

Pretty much, yeah. They're plastic fiber, you can buy them in different lengths and trim them to size with a side cutter or above some minimum order the company will cut them to length for you.

e: Datasheet link

PDP-1 fucked around with this message at 20:32 on Jan 20, 2024

ryanrs
Jul 12, 2011

I love it!

Optical hoses to connect your glowing crystals together, just like sci-fi tv shows promised.

kid sinister
Nov 16, 2002

ryanrs posted:

I love it!

Optical hoses to connect your glowing crystals together, just like sci-fi tv shows promised.

In my lifetime, fiber optics have gone from "state of the art" to "oh gently caress I forgot to panel mount my LED".

ANIME AKBAR
Jan 25, 2007

afu~

babyeatingpsychopath posted:

Why would a 2x2 dupont connector not work? Or even individual dupont connectors that you plug in individually? What's the driving factor for "retention" on a panel-mount LED?
A basic connector without a latch would probably work fine, if the connecting wires are secured near the connection so their own weight doesn't pull things apart (it's about 2ft of wire, which is plenty of weight). Unfortunately cable management was completely neglected during design of all the mechanical stuff. Adding an adhesive ziptie anchor would probably work fine, but they still believe that there must be a magic cable configuration which will make it unnecessary.

quote:

This now feels very much like a case of "the solution you're looking for isn't the actual problem you're trying to solve."
That's one way of putting it. Unfortunately the solution is more mechanical than electrical, but the mechanical engineers don't give a poo poo apparently.

Light pipes are another viable option (if they're available in such lengths), but mechanicals are even more critical for that so no reason to bother in this case.

ANIME AKBAR fucked around with this message at 15:27 on Jan 21, 2024

babyeatingpsychopath
Oct 28, 2000
Forum Veteran


ANIME AKBAR posted:

A basic connector without a latch would probably work fine, if the connecting wires are secured near the connection so their own weight doesn't pull things apart (it's about 2ft of wire, which is plenty of weight). Unfortunately cable management was completely neglected during design of all the mechanical stuff. Adding an adhesive ziptie anchor would probably work fine, but they still believe that there must be a magic cable configuration which will make it unnecessary.
That's one way of putting it. Unfortunately the solution is more mechanical than electrical, but the mechanical engineers don't give a poo poo apparently.

Engineers should be forced to repair things in their field for 2 (two) years before being allowed to design a product for production. Find something sufficiently heavy and blunt and retrain your engineers.

Remember: every tool has a hammer side... including monitors, oscilloscopes, and desk chairs.

ANIME AKBAR
Jan 25, 2007

afu~
Our device has like fifty cable assemblies most of them custom-made. Exactly zero are modeled in mCAD, even though we have the whole solidworks electrical routing tool. The most the MEs will do is export a view of the 3D assembly as a 2D image, then mark it up in mspaint or powerpoint with lines and arrows saying "cable X goes from here to here through here", and point to that when I complain that there's no cable management. But since those markups don't appear in solidworks, nobody ever sees it and so it might as well not exist (can't do an interference check on something you drew in loving mspaint).

The MEs are ultimately responsible for creating the drawings which define the cable assemblies, but the EEs must decide what goes in those drawings (connectors, pinout, whatever). That's fine, but if I ask the ME how long the cable should be, they will never actually give a precise number (because that would require modelling the cable), and just say "eh four feet ought to be plenty". Having an extra foot of slack is just not an issue to them, just loop it a few times and slap a zip tie on it! That's ok for the 22awg LED wires, but they also apply that to half inch diameter shielded cables and thin coax cables. They refuse to recognize that minimum bend radius is actually a thing that exists.

This all is positively reaffirmed by our boss during team meetings. I basically hear this every Tuesday:
https://twitter.com/dril/status/473265809079693312

ante
Apr 9, 2005

SUNSHINE AND RAINBOWS
That sounds infuriating, I don't know what to do if there is a work culture of just... Not doing your job.

Splode
Jun 18, 2013

put some clothes on you little freak
Sounds like it's time to find a new job. It's only going to get worse when the prototypes come back, they're poo poo because they were designed badly, and the "can you fix this? We don't want it to take any extra time or cost any extra, good luck thanks" begins.

SnoPuppy
Jun 15, 2005
When I’ve run into this behavior in the past, it’s been because the person/people in question didn’t actually know how to use their tools properly. This is especially true when it’s someone who’s been doing it for a while and the feature is new-ish.
It’s possible you could have better luck trying to talk to them 1:1 and see if you can “help” them to figure it out (or understand their real hold up).

For things like minimum bend radius, that’s something I’ve always dictated to MEs. Same for holding them accountable for managing service loop.

Shame Boy
Mar 2, 2010

Specify an extra 80 feet of cable and then make them find a place to put it

Giganticon
Mar 10, 2010

Pillbug
Does anyone have any rules of thumb for Japanese power? I keep getting tasked with making our machines work on 200VAC 50Hz. Most wide range high voltage stuff only goes down to 208VAC per data sheets.

A specific applications engineer for a polisci lab chiller told me the 220V 50Hz chiller will work fine but at reduced total output which is great. Now I have a bunch of motor controls stuff to sniff out, and a different compressor.

It's frustrating because I'm sure this is an advanced and well understood design challenge, as Japan is not a small market, but I don't know any of this stuff. If I cludge this and even if I test it out and it turns on and doesn't burn out over a weekend that doesn't really prove anything.

Also not sure how I test this stuff. I've got some huge variacs but no way to feed them 50 Hz power, which I assume if there's rectification is critical.

Stack Machine
Mar 6, 2016

I can see through time!
Fun Shoe

Giganticon posted:

Also not sure how I test this stuff. I've got some huge variacs but no way to feed them 50 Hz power, which I assume if there's rectification is critical.

The DIY route is probably mating an inverter with a kilowatt-class PC power supply. Other options are trying to source a generator or rent a fancy voltage/frequency converter. If you go cheap and try to use a PC power supply you'll have to figure out how to get all of the individual 12V wires out of their connectors and attached to some sort of common bus bar or wire securely, which isn't super difficult, but you're talking about space heater watts so you can't half-rear end it. If you decide to search for a generator I bet you could find a model with an easy-to-tune governor so you could set it to 45 Hz, and what's testing without a little margin to account for manufacturing and lifetime variation in component values? Meanwhile a decent inverter is probably crystal controlled so you're stuck with 50Hz to within 50ppm.

The expensive/easy route is renting something like this thing that doesn't even list the price on the website:

https://50hz.com/solid-state-frequency-converter/01kss6050/

It lets you select any frequency down to 45Hz. You should probably inquire about something like that. Either they'll offer you a good price and save you some risk or they'll give you a high price and you can later brag to your boss about how much money you saved (or to admit how much money you lost by taking a calculated risk and losing).

Shame Boy
Mar 2, 2010

Stack Machine posted:

The DIY route is probably mating an inverter with a kilowatt-class PC power supply. Other options are trying to source a generator or rent a fancy voltage/frequency converter. If you go cheap and try to use a PC power supply you'll have to figure out how to get all of the individual 12V wires out of their connectors and attached to some sort of common bus bar or wire securely, which isn't super difficult, but you're talking about space heater watts so you can't half-rear end it. If you decide to search for a generator I bet you could find a model with an easy-to-tune governor so you could set it to 45 Hz, and what's testing without a little margin to account for manufacturing and lifetime variation in component values? Meanwhile a decent inverter is probably crystal controlled so you're stuck with 50Hz to within 50ppm.

The expensive/easy route is renting something like this thing that doesn't even list the price on the website:

https://50hz.com/solid-state-frequency-converter/01kss6050/

It lets you select any frequency down to 45Hz. You should probably inquire about something like that. Either they'll offer you a good price and save you some risk or they'll give you a high price and you can later brag to your boss about how much money you saved (or to admit how much money you lost by taking a calculated risk and losing).

That company also sells a dynamotor version so obviously you should get that instead of the solid state one because it's cooler and also probably much louder.

Shame Boy
Mar 2, 2010

Why wouldn't you want your test bench to sound like a goddamn factory floor if given the option, I mean come on

e: I love this argument from their site

quote:

Rotary Design is easier to repair in the field and has far fewer components that are subject to failure and subsequent search for replacements that are no longer made.

... so does that mean your solid state machines use a bunch of parts that are no longer made??

LimaBiker
Dec 9, 2020




They really think for the long term. Motors and generators are still available in the same form factor as they were in the 1960s, but it's reasonable to expect that the current microcontrollers won't be around anymore in 20 years time while the industry standard motors/generators will keep being industrial lego parts.
They might keep boards in stock for a while, but i wouldn't be suprised if they wouldn't be able to supply boards for very old solid state converters.

babyeatingpsychopath
Oct 28, 2000
Forum Veteran


LimaBiker posted:

They really think for the long term. Motors and generators are still available in the same form factor as they were in the 1960s, but it's reasonable to expect that the current microcontrollers won't be around anymore in 20 years time while the industry standard motors/generators will keep being industrial lego parts.
They might keep boards in stock for a while, but i wouldn't be suprised if they wouldn't be able to supply boards for very old solid state converters.

The IGBTs also stop being made. I found a static phase converter that took up to 100A 480V 3-phase 60Hz and would output up to 75A 400V 400Hz. Some testing found one bad IGBT of 24. The IGBT wasn't made anymore, and all the warnings on all of the manuals said very loudly to not mix part numbers. The recommendation was to match LOT NUMBERS of the IGBTs and replace them 6 at a time (positive and negative on each of three phases) for best results.

Since these IGBTs were the size of coffee cans and 1980s-era parts books listed them at thousands of dollars each, we resigned ourselves to scrapping the thing.

The motor-genset this replaced had been returned to service after being plonked in a back room for most of a decade and still ran great. The motor part of it was a commercial unit from Westinghouse from no later than mid-70s.

derk
Sep 24, 2004
looking for some help.

So about 7 years ago i botched a soldering job on my OG xbox. i fixed the LPC pin header and got the chip installed, BUT

how hosed am i for the D0 wire i need to solder here (3rd hole down) and i can not get any solder to stay in the hole, i dont remember what i did years ago when i gave up and was frustrated.





https://imgur.com/RZ6ke7I
https://imgur.com/ie7nhVM
https://imgur.com/YDdPgnU

Shame Boy
Mar 2, 2010

derk posted:

looking for some help.

So about 7 years ago i botched a soldering job on my OG xbox. i fixed the LPC pin header and got the chip installed, BUT

how hosed am i for the D0 wire i need to solder here (3rd hole down) and i can not get any solder to stay in the hole, i dont remember what i did years ago when i gave up and was frustrated.





https://imgur.com/RZ6ke7I
https://imgur.com/ie7nhVM
https://imgur.com/YDdPgnU

Yeah looks like you lifted the pads (as in, you overheated a solder pad so much that it detached itself from the fiberglass backing and is completely gone now) so there's physically no metal left to actually solder to. Your options are:

1. Very gently scrape off the solder mask (the green stuff) from the trace going to the pad, and try to solder directly to the teeny tiny trace. I find this incredibly hard to do and I've been soldering teeny tiny things for over a decade.

2. Very gently scrape off the solder mask from the via that trace is going to, and solder to that. It's still teeny tiny, but slightly less so.

3. Try to figure out where that trace eventually winds up, hope and pray it's physically large enough to solder to when you find it, and solder to that instead. Using a multimeter in the continuity test mode (the mode where it beeps when you touch the probes together) can help you figure out what's connected to what, but I'm guessing this is a pretty complicated-rear end circuit board with several different layers so that's gonna be... hard... Though whatever chip you're trying to install probably has documentation somewhere about what it's connecting to that might be able to help narrow down where to look.

I annotated your picture to try and show what I mean with 1 and 2 since I realized I'm throwing out a lot of circuit board words that may or may not be clear to someone who's not a complete and total turbo-dork like me:



Personally I'd go with 2 unless you can easily figure out where that trace winds up and do 3 instead.

e: For scraping off solder mask you can use some sandpaper (like 400 or 800 grit would be best I'd imagine), though in a pinch I've done it by scraping a utility knife across it, like not cutting but scraping the blade almost perpendicular across if that makes sense. It's just a thin layer of what's basically enamel paint so it should come off pretty easy.

Shame Boy fucked around with this message at 20:47 on Jan 24, 2024

derk
Sep 24, 2004

Shame Boy posted:

Yeah looks like you lifted the pads (as in, you overheated a solder pad so much that it detached itself from the fiberglass backing and is completely gone now) so there's physically no metal left to actually solder to. Your options are:

1. Very gently scrape off the solder mask (the green stuff) from the trace going to the pad, and try to solder directly to the teeny tiny trace. I find this incredibly hard to do and I've been soldering teeny tiny things for over a decade.

2. Very gently scrape off the solder mask from the via that trace is going to, and solder to that. It's still teeny tiny, but slightly less so.

3. Try to figure out where that trace eventually winds up, hope and pray it's physically large enough to solder to when you find it, and solder to that instead. Using a multimeter in the continuity test mode (the mode where it beeps when you touch the probes together) can help you figure out what's connected to what, but I'm guessing this is a pretty complicated-rear end circuit board with several different layers so that's gonna be... hard... Though whatever chip you're trying to install probably has documentation somewhere about what it's connecting to that might be able to help narrow down where to look.

I annotated your picture to try and show what I mean with 1 and 2 since I realized I'm throwing out a lot of circuit board words that may or may not be clear to someone who's not a complete and total turbo-dork like me:



Personally I'd go with 2 unless you can easily figure out where that trace winds up and do 3 instead.

e: For scraping off solder mask you can use some sandpaper (like 400 or 800 grit would be best I'd imagine), though in a pinch I've done it by scraping a utility knife across it, like not cutting but scraping the blade almost perpendicular across if that makes sense. It's just a thin layer of what's basically enamel paint so it should come off pretty easy.

thank you for the insight. it is actually 1 more to the left but i get the gist of what you are saying. so do i solder to the via (the circle)? the trace goes to a chip on the other side of the board, i am assuming just 1 pin of the chip. gently caress this might be out of my league, it is so tiny and my hands do not hold very steady, flux saves my rear end, but these are super tiny.

Shame Boy
Mar 2, 2010

derk posted:

thank you for the insight. it is actually 1 more to the left but i get the gist of what you are saying. so do i solder to the via (the circle)? the trace goes to a chip on the other side of the board, i am assuming just 1 pin of the chip. gently caress this might be out of my league, it is so tiny and my hands do not hold very steady, flux saves my rear end, but these are super tiny.

Yeah you'd carefully sand/scrape off the solder mask from the via (which yeah, it's the circle thing, it's basically a conductive stud that goes through the board so you can get a signal from one side of the board to the other), then solder directly to the via. If you do in fact know what chip it's going to you can also try to figure out which pin on the chip you need to connect, but thinking about it unless it's a pretty simple chip I'm guessing the pins are going to be teeny tiny too so that might not be much better...

kid sinister
Nov 16, 2002

derk posted:

looking for some help.

So about 7 years ago i botched a soldering job on my OG xbox. i fixed the LPC pin header and got the chip installed, BUT

how hosed am i for the D0 wire i need to solder here (3rd hole down) and i can not get any solder to stay in the hole, i dont remember what i did years ago when i gave up and was frustrated.





https://imgur.com/RZ6ke7I
https://imgur.com/ie7nhVM
https://imgur.com/YDdPgnU

This is very salvageable. I've seen much worse.

FYI, those holes are called vias. Their job is to connect traces on different levels of the board.

derk
Sep 24, 2004

Shame Boy posted:

Yeah you'd carefully sand/scrape off the solder mask from the via (which yeah, it's the circle thing, it's basically a conductive stud that goes through the board so you can get a signal from one side of the board to the other), then solder directly to the via. If you do in fact know what chip it's going to you can also try to figure out which pin on the chip you need to connect, but thinking about it unless it's a pretty simple chip I'm guessing the pins are going to be teeny tiny too so that might not be much better...

thank you so much, i thought i was totally hosed here. i am going to give this a whirl during the week or over the weekend. I shall report back with progress, hopefully no problems.

derk
Sep 24, 2004

kid sinister posted:

This is very salvageable. I've seen much worse.

FYI, those holes are called vias. Their job is to connect traces on different levels of the board.

well, that is good to know! i didn't screw it up beyond repair

kid sinister
Nov 16, 2002

derk posted:

well, that is good to know! i didn't screw it up beyond repair

Now the hard part: you'll need to work with the itsiest-bitsiest wire you've ever seen: 30 gauge kynar wire.

One Legged Ninja
Sep 19, 2007
Feared by shoe salesmen. Defeated by chest-high walls.
Fun Shoe
Expo70 and

Shame Boy posted:

a question about steppers and servos

I just got this short video about testing open and closed loop steppers and servos in my feed. He does a side-by-side thermal video of four different devices at idle current, and tests maximum acceleration and speed. Not the most exhaustive testing, and doesn't really answer your previous question, but interesting nonetheless. And he mentioned you can get closed-loop steppers premade on the usual Chinese sites.

Edit: oops, I was phone posting and put the wrong link in.

One Legged Ninja fucked around with this message at 18:39 on Jan 25, 2024

Shame Boy
Mar 2, 2010

One Legged Ninja posted:

Expo70 and

I just got this short video about testing open and closed loop steppers and servos in my feed. He does a side-by-side thermal video of four different devices at idle current, and tests maximum acceleration and speed. Not the most exhaustive testing, and doesn't really answer your previous question, but interesting nonetheless. And he mentioned you can get closed-loop steppers premade on the usual Chinese sites.

Oh neat, thanks :shobon:

I think you messed up the link though, since the URL is just linking to your own posts in this thread and not a video :v:

e: Unless you were linking to that post where you just sorta describe a video you saw once about stepper motors? Maybe??

e2: And I've used closed-loop steppers before plenty but the loop they close tends to be more "did it or did it not step" which is useful if all you're trying to do is ensure your thing is actually moving but not that helpful when you want the thing to be able to be resisted. In my experience if you resist a closed-loop stepper for more than a few seconds the controller just decides it must be jammed, shuts off the output to avoid burning out and raises an error signal.

Shame Boy fucked around with this message at 16:28 on Jan 25, 2024

Shame Boy
Mar 2, 2010

Unrelated but I'm looking at PoE accessories for raspberry pi's and saw this thing, and was like "the gently caress, are those pogo pins"



And sure enough, yes they totally are:



Not sure I trust those pins to be able to move the 2A they say this thing can source but I love the audacity of trying anyway.

Acid Reflux
Oct 18, 2004

Once the arc welds them to the contact pads, they'll be able to carry the full 2A. :v:

Fanged Lawn Wormy
Jan 4, 2008

SQUEAK! SQUEAK! SQUEAK!
I have a question related to motor control and power.
I'm looking at using this Roboclaw Motor Controlle to control a large 12VDC fan. (think like a radiator fan for a car).
I was looking at the hardware precautions, and noticed this bit about a Bypass Diode: https://resources.basicmicro.com/motor-controller-hardware-precautions/

Should I worry about this if I'm using a big ol' switching 12V PSU? Are there any other precautions in terms of long term electrical wear/protection I should take?

One Legged Ninja
Sep 19, 2007
Feared by shoe salesmen. Defeated by chest-high walls.
Fun Shoe

Shame Boy posted:

Oh neat, thanks :shobon:

I think you messed up the link though, since the URL is just linking to your own posts in this thread and not a video :v:

e: Unless you were linking to that post where you just sorta describe a video you saw once about stepper motors? Maybe??


Oops, no, I was phone posting with a baby on the other arm and pasted the wrong link.

Here's the right link.

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ryanrs
Jul 12, 2011

Fanged Lawn Wormy posted:

Should I worry about this if I'm using a big ol' switching 12V PSU? Are there any other precautions in terms of long term electrical wear/protection I should take?

Yeah, the braking current will throw the PSU into fault mode and shut down. You need a voltage clamp or similar to eat the regen voltage spike so it doesn't trip the PSU's overvoltage protection.

When I built a system using Roboclaw controllers, I designed my own braking circuit specifically because of this issue. But I see they now sell their own: RoboClaw VClamp accessory $20.

You will need this VClamp, or something similar, if you are going to have braking on your large fan. Maybe you can configure the RoboClaw to never use braking, but that is not the default.

e: Don't use a bypass diode. That is for battery use only (so regen braking still works if the fuse pops).

ryanrs fucked around with this message at 19:09 on Jan 25, 2024

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