Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

@bd139 and Cerebus If your both thinking about getting a dashcam, you could do a lot of worse than getting a NextBase 512GW, there are plenty of videos about it on YT and it also has the ability to add a rear camera and record both at the same time. I myself have one and only have the front unit which as a single unit will also record at 1440 HD+, has Wi-Fi built in which will pair up with a mobile phone for file transfer. I like it a lot.

This was prompted by the number of attempted suicide victims I met on the roads today who seemed to want to make me the means of their exit from the world.

I did have one last year but had to RTM/RMA it because half the video it recorded was scrambled. That was a NextBase, forget which model, so I'm not going there again. I just picked on BD139 for a recommendation becuase of him mentioning one he was using a while back and I trust his judgement. Turns out that one fried itself in the summer. He got a recommendation from one of his colleagues that looks hopeful.

Well that one you had was just bad luck I'd guess, why do I say this? Because I'm on my 2nd NextBase one and so there is no misunderstanding here, I still have the first one which is a NextBase 402G which I have had for 8 years and its been RTM once for a new battery under warranty. This year I decided to purchase an upgraded one from the 1080p to 1440p resolution with Wi-Fi for easier file transfer.  In that time I have been involved in 2 accidents and the camera was worth its weight in gold as it clearly proved that both times I was the innocent party. Before I discovered NextBase I had tried a slightly cheaper one and was far from impressed with the quality of its video, though I still also have that one and it's also working OK. Both of my models from NextBase are towards the top of the model range but not that expensive. The software supplied with them also works with Google Maps so during playback of the video on a computer, you can see the video along with  the cars actual position shown on the map which is really useful as it records the time, date, position and speed of your car and the map provides street names or road numbers if in a strange location.

[Cerebus]

@bd139 and Cerebus If your both thinking about getting a dashcam, you could do a lot of worse than getting a NextBase 512GW, there are plenty of videos about it on YT and it also has the ability to add a rear camera and record both at the same time. I myself have one and only have the front unit which as a single unit will also record at 1440 HD+, has Wi-Fi built in which will pair up with a mobile phone for file transfer. I like it a lot.

This was prompted by the number of attempted suicide victims I met on the roads today who seemed to want to make me the means of their exit from the world.

I did have one last year but had to RTM/RMA it because half the video it recorded was scrambled. That was a NextBase, forget which model, so I'm not going there again. I just picked on BD139 for a recommendation becuase of him mentioning one he was using a while back and I trust his judgement. Turns out that one fried itself in the summer. He got a recommendation from one of his colleagues that looks hopeful.

Well that one you had was just bad luck I'd guess, why do I say this? Because I'm on my 2nd NextBase one and so there is no misunderstanding here, I still have the first one which is a NextBase 402G which I have had for 8 years and its been RTM once for a new battery under warranty. This year I decided to purchase an upgraded one from the 1080p to 1440p resolution with Wi-Fi for easier file transfer.  In that time I have been involved in 2 accidents and the camera was worth its weight in gold as it clearly proved that both times I was the innocent party. Before I discovered NextBase I had tried a slightly cheaper one and was far from impressed with the quality of its video, though I still also have that one and it's also working OK. Both of my models from NextBase are towards the top of the model range but not that expensive. The software supplied with them also works with Google Maps so during playback of the video on a computer, you can see the video along with  the cars actual position shown on the map which is really useful as it records the time, date, position and speed of your car and the map provides street names or road numbers if in a strange location.

Eh, maybe I'll take a second look. You know how it is if you get a duff one, it tends to sour you to the whole manufacturer. Unfair perhaps, but it's what we all do.

[mnementh]

There is no sine wave generation here;

Yeah, there is. Well, more often a dirty trapezoidal approximation. I just don't think you've realised it's there. Just as the PWM burried inside an old ARB from the days before fast DACs can produce a sine wave when filtered, so does the PWM from motor controller when filtered through the resistance and inductance of the motor windings. (Some motors have windings distributed in such a way that at trapezoid is the right way to drive them, some want a pukka sinewave.)

These show phase to ground voltages on the output of an RC model's ESC. Remember this is a three phase Y motor so to get phase-to-phase voltages or phase-to-Y you have to do some arithmetic on the waveforms shown to get there.

Look at the envelope -  a messy trapezoid.

   Similar sort of thing:   

Oh, good lord, here we go again; same old argument as trying to explain to a plank pilot why quadcopter ESCs need to be so different from plank ESCs... 

That's a waveform from an old eFlite plank ESC; literally more than a decade old in terms of design technology. They operate at about 1/100 the RPMs of a modern quadcopter ESC, and they were DELIBERATELY trying to do MSW the same way as some AC inverters do to get "smoother power" because low-KV motors will shake a wooden craft to bits if they start "cogging" at low RPM. They were able to do this because the demands were so low on the processor. Many of these ESCs actually have a governor feature in them that can be turned on to provide a fixed RPM for helicopter use.

That is literally not even the same species as a multirotor ESC. Yeah, sure, you can see something sortof like that waveform with a multirotor motor & ESC... only far fewer steps in the waveform and a lot more noise because it is literally commutation going on (the ESC people's term, not mine), not any attempt at sine wave generation.

I spent a lot of time at the beginning of my multirotor journey trying to reconcile my conventional knowledge of conventional industrial speed control with how these ESCs work. In the end, I came to realize this was not a case of "derivative" as much as "divergent evolution" from a really old fork in the way back when. The needs of an aircraft that uses varying speeds of motors to fly, steer and keep itself level are completely different from anything that has gone before. As long as you keep trying to fit MR ESCs into any existing boxes, the less sense they'll make.

mnem

The exact model of ESC doesn't matter - I just did an image search and picked the first couple of waveforms that looked right. What matters is that it controlling a BLDC motor.

Mnem, this is about how BLDC/PMSM motors work, no more no less. It has nothing to do with the application. BLDC motors do not blow themselves up if they have no load, etc. etc. It doesn't matter is the BLDC motor is a lift motor on a quadcopter or a servo on a CNC axis, it's still a BLDC motor. I've got two of the quadcopter type external rotor motors here, I've also got two small circa 50W "just a motor" BLDC motors. They are all the same electrically. Three phases, Y wired, a bunch of stator poles, a bunch of permanent magnet poles, that's it all for the 'motor' part. They take the same electrical signals to make them go around in the same way, the physics of magnetism dictate how they work, they all work the same. The torque/speed curves of all of them are the same fundamental shape and so on.

By pure coincidence I've spent some not inconsiderable amount of my time for the last few months reading real text books on the subject, watching loads of videos on the subject, including the whole of a two day TI seminar on the topic. I don't claim to be an expert, but I can claim to know enough to say "Hold on, that doesn't sound right" or "Yeah, that sounds right". Robert clearly knows what he's talking about. A lot of what you've said doesn't make sense. I pitched in to try to give you a face saving way of coming around and you're refusing to take it. So be it, it's your loss.

I don't need to save face. I've tried to explain a very complex and specialized niche technology as best I can; you insist these ESCs must work in a way that is simply beyond their capacity. Whatever works for you.  I really am beyond caring at this point. I'm wrong. I can live with that. I'll keep being wrong. Thanks for the opportunity!

Like I said, there's a reason multirotor ESCs have literally been evolving at an exponential rate over the last decade... these changes in the technology are why I've gotten rid of drawers full of obsolete ESCs that aren't good for anything except a plank.

But hey... it doesn't matter. I'll let you learn all the lessons I did the hard way if you ever get into acro & race quads. That's the only way you'll really understand.

mnem

[Specmaster]

@bd139 and Cerebus If your both thinking about getting a dashcam, you could do a lot of worse than getting a NextBase 512GW, there are plenty of videos about it on YT and it also has the ability to add a rear camera and record both at the same time. I myself have one and only have the front unit which as a single unit will also record at 1440 HD+, has Wi-Fi built in which will pair up with a mobile phone for file transfer. I like it a lot.

This was prompted by the number of attempted suicide victims I met on the roads today who seemed to want to make me the means of their exit from the world.

I did have one last year but had to RTM/RMA it because half the video it recorded was scrambled. That was a NextBase, forget which model, so I'm not going there again. I just picked on BD139 for a recommendation becuase of him mentioning one he was using a while back and I trust his judgement. Turns out that one fried itself in the summer. He got a recommendation from one of his colleagues that looks hopeful.

Well that one you had was just bad luck I'd guess, why do I say this? Because I'm on my 2nd NextBase one and so there is no misunderstanding here, I still have the first one which is a NextBase 402G which I have had for 8 years and its been RTM once for a new battery under warranty. This year I decided to purchase an upgraded one from the 1080p to 1440p resolution with Wi-Fi for easier file transfer.  In that time I have been involved in 2 accidents and the camera was worth its weight in gold as it clearly proved that both times I was the innocent party. Before I discovered NextBase I had tried a slightly cheaper one and was far from impressed with the quality of its video, though I still also have that one and it's also working OK. Both of my models from NextBase are towards the top of the model range but not that expensive. The software supplied with them also works with Google Maps so during playback of the video on a computer, you can see the video along with  the cars actual position shown on the map which is really useful as it records the time, date, position and speed of your car and the map provides street names or road numbers if in a strange location.

Eh, maybe I'll take a second look. You know how it is if you get a duff one, it tends to sour you to the whole manufacturer. Unfair perhaps, but it's what we all do.

Yep, its like Samsung TV's, many people have had bad experiences with them and won’t touch em with a barge pole, me, I have had many over the years and they have all been perfect TV's, only got rid of them each time as upgrading to a bigger and better model after a number of years. I have had problems in the past with both Phillips and also Toshiba though.

With the dash cam, take a look on Amazon, I got my 512GW there a few months ago for less than half price, supposed to be a refurb but seemed to be a factory sealed box to me and came with a full makers warranty/

[Cerebus]

Mnem, fine. Your magic BLDCs are different to everybody else's BLDCs and operate with physics that can only be known to the cognoscenti.

Why do you keep doing this to yourself. Why do you refuse to admit that there are people, like Robert, who know what they're talking about, and when they say "No, sorry that's wrong" you go off on one and shout and shout and shout until you think you've beaten the 'opposition' into submission. Has it passed your notice that people are openly commenting on that behaviour, that you now have a reputation for it. Doesn't that give you pause for thought. I bet at school you were the smartest kid in the room and always got the answers right, but you're not at school now, and you're on a board where you can't know everything better than everybody else.

All that you're doing is teaching people that you are unteachable. More and more people are just going to quietly ignore it when you get things wrong, because they know what's coming - the storm of shouting. You've certainly taught me that to dare to correct you in any form, no matter how gently or circumspectly, is just going to result in shit. I thought I'd have one last try, it failed. ENDS

[Cerebus]

With the dash cam, take a look on Amazon, I got my 512GW there a few months ago for less than half price, supposed to be a refurb but seemed to be a factory sealed box to me and came with a full makers warranty/

As I've said before, I boycott Amazon. I refuse to put money into that shitshow of appalling labour practices etc. etc. I can't do much to personally improve the world, but at least I can withhold my custom from those who seem to be determined to lead the race to the bottom. Thanks for the heads up anyway.

[battlecoder]

I've been going over MANY posts during the past week trying to decide between a Rigol DG822 and a Uni-T UTG962E signal generator, and I just can't make the call.
Getting the cheaper DG811 (which is a pretty good value for money given the..uh..."modding" capabilities) is not an option since the lowest I can get here from a reliable source is the 822. This means that I can't really increase the bang-for-buck ratio on that one. I'll need to go straight for the "mid-range" unit in that family of devices.

So far this is what I've collected:
Rigol
Pros: Wide range of modulation and signal options to simulate bursts, serial data, sequences of different signals, etc. Can be connected to an external 10Mhz reference. Can be modded up to 50Mhz without(?) issues ? (higher freq is possible but in entirely uncalibrated territory). Can purchase locally; That means warranty and tech support, and the option to pretty much have it here within 2 days time.
Cons: Higher price. Weird physical shape / size. Apparently suffers from software bugs and jitter (still better than what I currently have though).

Uni-T:
Pros: Considerably cheaper. Smaller form factor (pretty good for a tiny workbench like mine). Good phase stability and signal quality apparently. Goes up to 60Mhz without hacks.
Cons: Awfully basic modulation options (limited types, most of them only accept internal modulation. Only FSK accepts external signal), and limited "complex" waveforms. User-provided arbitrary waves are not persistent, and do not survive power off. Will need to buy it online, so might get stuck on customs, meaning there's a chance I won't be having my hands on it before next year.

I don't think I'll need the advanced features of the Rigol anytime soon, but the rather lacking modulation / waveform options of the Uni-T make me thing I'll outgrow its features real quick.

Maybe I should spend a year designing and building my own frequency generator, or save for one so expensive that the only "issue" it could possibly have is that it doesn't transform into a car 

[cyclin_al]

I would just like to apologise to everyone for posting such a contentious explosion 

I’d like to share the following as a less contentious one to refresh people:

https://youtu.be/pXI1PDTp5gk

Naaaah!  What's up Doc?

What's up is there is no need to apologize.  This discussion is educating me well beyond my grossly simplified understanding (which seems to be roughly correct).  Keep up these discussions; you all are inspiring me to think 

[mnementh]

Mnem, fine. Your magic BLDCs are different to everybody else's BLDCs and operate with physics that can only be known to the cognoscenti.

Why do you keep doing this to yourself. Why do you refuse to admit that there are people, like Robert, who know what they're talking about, and when they say "No, sorry that's wrong" you go off on one and shout and shout and shout until you think you've beaten the 'opposition' into submission. Has it passed your notice that people are openly commenting on that behaviour, that you now have a reputation for it. Doesn't that give you pause for thought. I bet at school you were the smartest kid in the room and always got the answers right, but you're not at school now, and you're on a board where you can't know everything better than everybody else.

All that you're doing is teaching people that you are unteachable. More and more people are just going to quietly ignore it when you get things wrong, because they know what's coming - the storm of shouting. You've certainly taught me that to dare to correct you in any form, no matter how gently or circumspectly, is just going to result in shit. I thought I'd have one last try, it failed. ENDS

All the things I've tried to explain are literally common knowledge in quadcopter building/racing circles. Ryan is one of my oldest friends in the community; this PSU was built for him and his test bench because he asked if I could come up with a AC power supply that could handle the crazy current surge of modern 6S setups without sagging halway through a run like a 6S LiPo would.




Ryan has been my motor & ESC sherpa for years and we've had a great many conversations like the one above; I've also had a few similar ones with Steffen Skaug, the creator of BLHeli. I'll admit most of those conversations went way over my head, but Steffen was a really decent guy too. I've spoken a few times with JB too, but only briefly regarding the SmokeStopper.

I was working on may of the assumptions you are making based on prior experience with industrial motor control; it was Ryan who was able to explain the differences. These ESCs work very differently from anything that has come before, because they have to change motor speed very quickly. There literally is not enough time to generate a complete pseudo-sinewave every commutation cycle the way you're talking about. There are times when the demand for speed changes before a single motor rotation completes. They simply cannot work the way you demand that they must.

And yes, as is mentioned here, you can have exactly what I describe as desync, for exactly the reason I explain: Because the ESC cannot correctly sense the reverse-EMF it needs to start the next commutation cycle. When a motor is loaded this just causes missed timing events and sometimes it goes into shutdown. With no load, desync can definitely happen fast and hard enough to cause a shorted FET even on 3S & 4S voltages, the same way as is discussed here. It has happened to me on my own test bench. I have also seen it happen in the air on a quad that was badly tuned and another that grenaded a prop.

So no, this time it's not me buddy.

Cheers,

mnem
*toddling off to ded*

[med6753]

Is it safe to poke my head in and look around? 

All appears to be quiet. Looks like the combatants are sleeping. 

I suspect there's gonna be some hangovers today.     

[tautech]

Is it safe to poke my head in and look around? 

All appears to be quiet. Looks like the combatants are sleeping. 

I suspect there's gonna be some hangovers today.     

Just working on one now.
Mate that uses our shooting range dropped off a 40oz of his home brew bourbon and it's pretty good. What the morning will look like is anybodys guess ! 
Discord might be missed........

[med6753]

At least you'll sleep well. 

[tggzzz]

Mate that uses our shooting range dropped off a 40oz of his home brew bourbon and it's pretty good. What the morning will look like is anybodys guess ! 

Homebrew spirits? Hope the morning will look like anything!

Is fractional crystallisation a realistic way of making spirits?

[med6753]

Sounds like an NZ version of moonshine. 

[Saskia]

they made that completely illegal over here. Previously (2 years or so ago) you were allowed a minimalistic home brew/distill approach. Now they consider possession of a small distill thingy a crime worthy of raiding your home with a swat team.

[Specmaster]

I would just like to apologise to everyone for posting such a contentious explosion 

I’d like to share the following as a less contentious one to refresh people:

https://youtu.be/pXI1PDTp5gk

Naaaah!  What's up Doc?

What's up is there is no need to apologize.  This discussion is educating me well beyond my grossly simplified understanding (which seems to be roughly correct).  Keep up these discussions; you all are inspiring me to think 

Exactly that, it is educating the rest of us as well as being mildly entertaining and sometimes it is good to have these discussions and debates and you can picture in your mind, Mnementh stoking his boiler to ensure his flames don't go out and Cerebus getting out his ceremonial cutlery out and polishing it ready to do battle together. Its part and parcel as far as I'm concerned of a very healthy and buoyant board and explains why this board is the number 1 thread on the forum and long may it continue to be so 

[Specmaster]

Is it safe to poke my head in and look around? 

All appears to be quiet. Looks like the combatants are sleeping. 

I suspect there's gonna be some hangovers today.     

Just get your big bag of popcorn and soft drinks out, the show might rumble a bit more yet 

[Specmaster]

With the dash cam, take a look on Amazon, I got my 512GW there a few months ago for less than half price, supposed to be a refurb but seemed to be a factory sealed box to me and came with a full makers warranty/

As I've said before, I boycott Amazon. I refuse to put money into that shitshow of appalling labour practices etc. etc. I can't do much to personally improve the world, but at least I can withhold my custom from those who seem to be determined to lead the race to the bottom. Thanks for the heads up anyway.

I admire your ethics but for me, sadly economics won't allow me that particular luxury, for me it's generally the cheapest price will get my order unless there is another close price from a more reliable or reputable supplier.   

[xrunner]

Is it safe to poke my head in and look around? 

All appears to be quiet. Looks like the combatants are sleeping. 

[bd139]

With the dash cam, take a look on Amazon, I got my 512GW there a few months ago for less than half price, supposed to be a refurb but seemed to be a factory sealed box to me and came with a full makers warranty/

As I've said before, I boycott Amazon. I refuse to put money into that shitshow of appalling labour practices etc. etc. I can't do much to personally improve the world, but at least I can withhold my custom from those who seem to be determined to lead the race to the bottom. Thanks for the heads up anyway.

I admire your ethics but for me, sadly economics won't allow me that particular luxury, for me it's generally the cheapest price will get my order unless there is another close price from a more reliable or reputable supplier.   

Regarding Amazon, they're singled out as a major issue but the reality is that the abusive shit show is the entire retail and distribution industry which is being very bloody quiet while Amazon is taking all the flak. Even that cute little rip off "local business" bookseller populated by an angry Irish drunk is buying from the same class of supply chain, run by zero hour contracts and abusive labour practices, even if they bother to pay their own employees properly. Small businesses are even worse.

YMMV but living in the woods is your only ethical way to escape such constraints so I'd rather not punch myself in the balls to make a point even if I do agree with it

The best thing you can do is navigate yourself into a position of power where you can change things, but alas that's not possible for most people so being a sucker it is.

[capt bullshot]

Anyway here is a picture of the display, I think I have worked out what it is and it's not a VFD.


It's quite heavy for it's size too (over 21kg) & only has one carrying handle, hopefully the fan will be super noisy. 

David

Looks like an LCD. Rather boring if this should be true

[Cerebus]

With the dash cam, take a look on Amazon, I got my 512GW there a few months ago for less than half price, supposed to be a refurb but seemed to be a factory sealed box to me and came with a full makers warranty/

As I've said before, I boycott Amazon. I refuse to put money into that shitshow of appalling labour practices etc. etc. I can't do much to personally improve the world, but at least I can withhold my custom from those who seem to be determined to lead the race to the bottom. Thanks for the heads up anyway.

I admire your ethics but for me, sadly economics won't allow me that particular luxury, for me it's generally the cheapest price will get my order unless there is another close price from a more reliable or reputable supplier.

The problem is that, as you say, Amazon is often the cheapest source, and it's so easy. I can't blame anyone else for taking it, so don't think I'm ragging on you. I keep finding myself tempted and sometimes you just can't find anybody else carrying something you're looking for, or if you can there's a significant price difference. A while back there was a particular motherboard, one with one of the Atom chips with a high core count that looked like a nice way to build a low power server for messing with VMWare - only place I could find one at a sane price was Amazon, anyone else who had one in the UK was hundreds of pounds more. Didn't go down that route in the end, but I would have had to think hard about it if I'd decided to get one.

And, having read on: BD's got a point. Amazon is visible and perhaps I'm just being an enabler somewhere else that is less visible, thus all I'm doing is salving my conscience and having no actual effect. It's a bit like being the Landlord of some flat roof pub is some area endemic with crooks and barring the one customer you know is guilty as all sin and still being a jovial 'Mein Host' to all the other villains in blissful ignorance.

[bd139]

Thing I find is I don’t use amazon for the best price but the fastest turnaround and lowest risk. A lot of the time it’s more expensive.

Tesco is a far more dangerous company. (I am in their temple now)

Edit: just to clarify that super mega corporations tend to form not out of monopolistic desires (well some do) but more that their existential growth is required to keep up with growth of society and supply as general wealth increases. It’s the only way to scale up.  Fine example is the recent covid mess - we may have come off worse without central coordination at national level from the supply chains. At best we had a bog roll shortage.

[Brumby]

Is it safe to poke my head in and look around? 

All appears to be quiet. Looks like the combatants are sleeping. 

Do so at your own peril.

This little black duck has said all I wanted to say - and will be steering clear, unless invited by Med.

[med6753]

Is it safe to poke my head in and look around? 

All appears to be quiet. Looks like the combatants are sleeping. 

Do so at your own peril.

This little black duck has said all I wanted to say - and will be steering clear, unless invited by Med.

Well at our Discord session later today I'll give you all the opportunity to listen to that obnoxious fan and judge for yourself.