A step toward fully 3D-printed active electronics(news.mit.edu)
news.mit.edu
A step toward fully 3D-printed active electronics
https://news.mit.edu/2024/mit-team-takes-major-step-toward-fully-3d-printed-active-electronics-1015
85 comments
I want to clarify that they actually did build a transistor-like device, and not just hypothesize about it. I missed section 3.2 when I initially skimmed the paper, which demonstrates and shows the results of a working “transistor”.
Unfortunately I can’t edit my original post, so apologies for causing any confusion.
Unfortunately I can’t edit my original post, so apologies for causing any confusion.
This image shows logic gates they made:
https://www.tandfonline.com/cms/asset/5043deae-e79e-45fc-bb7...
https://www.tandfonline.com/cms/asset/5043deae-e79e-45fc-bb7...
It’s cool for tinkering, and I think there are lots of potential use-cases for conductive filaments and printing in electronics, but I don’t think transistors are necessary. Silicon crystal development is really already a sort of “additive manufacturing”, and I’m not sure what purpose would be served by re-inventing a method that would be starting so far behind in terms of scale, precision, and cost in relation to traditional semiconductor production (anyway, I assume this idea is broadly for learning/experimentation/the lols, rather than some earnest aspiration for using metal-bearing printer filaments to produce active components).
What about the use of power transistors that don't too well as silicon crystals afaik.
[deleted]
Hang on, can you explain why this is passive and not active?
> Harnessing the described phenomenon, we created the first semiconductor-free active electronic devices fully 3D printed via material extrusion. We demonstrate this breakthrough through the implementation of monolithically 3D-printed logic gates.
> Harnessing the described phenomenon, we created the first semiconductor-free active electronic devices fully 3D printed via material extrusion. We demonstrate this breakthrough through the implementation of monolithically 3D-printed logic gates.
They've created a Polymeric Positive Temperature
Coefficient (PPTC) device. As it heats up the resistance gets very high very abruptly.
While it is non-linear, diodes are also considered passive devices[2], as active is taken to mean electrical control of current flow.
In this case one could induce current control through thermal means, ie an adjacent heating element, and if you potted that in a box I guess you could argue the box is an active device. But not the PPTC itself.
[1]: https://m.littelfuse.com/~/media/electronics/technical_paper...
[2]: https://wiki.analog.com/university/courses/electronics/text/...
While it is non-linear, diodes are also considered passive devices[2], as active is taken to mean electrical control of current flow.
In this case one could induce current control through thermal means, ie an adjacent heating element, and if you potted that in a box I guess you could argue the box is an active device. But not the PPTC itself.
[1]: https://m.littelfuse.com/~/media/electronics/technical_paper...
[2]: https://wiki.analog.com/university/courses/electronics/text/...
Unlike a device with positive temperature coefficient, the NTC thermistors (negative temperature coefficient) can be used by themselves as active devices that provide a negative resistance, which can be used to make amplifiers and oscillators, exactly like with any other diodes with negative resistance, e.g. tunnel diodes, IMPATT diodes, Gunn diodes, Shockley diodes, diacs and so on.
Nevertheless, I do not think that anyone has ever made amplifiers or oscillators with thermistors, because unlike the diodes where the negative resistance has electrical causes, the inertia of the heat transfer in thermistors makes the achievable upper limit for the amplified frequencies very low, typically under 1 Hz.
A device with positive temperature coefficient could be used as an amplifier or as a switch (like a relay) only together with a separate heater, as you say.
Nevertheless, I do not think that anyone has ever made amplifiers or oscillators with thermistors, because unlike the diodes where the negative resistance has electrical causes, the inertia of the heat transfer in thermistors makes the achievable upper limit for the amplified frequencies very low, typically under 1 Hz.
A device with positive temperature coefficient could be used as an amplifier or as a switch (like a relay) only together with a separate heater, as you say.
I have seen old organs which used solid state VCOs that also had an incandescent lightbulb near the circuit boards to help maintain a stable temperature, and had thought they must use a thermistor although I seem to be mistaken as I can't find much information about that.
I did find this however:
https://northcoastsynthesis.com/news/temperature-compensatio...
I did find this however:
https://northcoastsynthesis.com/news/temperature-compensatio...
> active is taken to mean electrical control of current flow
Is a transformer an active device? Asking because current in one loop can control current in the other loop.
From there, are two copper wires an active device?
Is a transformer an active device? Asking because current in one loop can control current in the other loop.
From there, are two copper wires an active device?
The current in one transformer loop does not control the current in the other loop.
The power from one loop is transferred into the other, there is no control. The same for two copper wires.
"Control" means that you can determine the value of the power in some circuit by consuming less power to do this. If you have to use the same power, not less, then you are the provider of power, not someone in control, i.e. this is the difference between bosses and the workers commanded by them. The bosses do not lift heavy parcels themselves, they order to some worker to do that.
A device that apparently looks like a transformer but it is an active device is the magnetic amplifier. There are 2 differences from a transformer, the magnetic core is saturable during normal operation (any magnetic core is saturable at a high enough magnetic field, but when that happens in a transformer this means that the transformer has failed, which leads to overcurrents that would destroy the equipment unless a protection is triggered), and the second difference is that the control coil has a very high number of turns, so that a very small current can saturate the magnetic core.
In a magnetic amplifier, the output coil is inserted in an AC circuit where the power must be controlled. When the core is not saturated, the impedance of the coil is high and the output AC current is low. When the core is saturated, the impedance of the coil is low and the output AC current is high. Whether the magnetic core is saturated or not is controlled with a very small current and power on the control coil, which makes this an active device.
Magnetic amplifiers have been heavily used during WWII, especially by the Germans, who had improved them, and they continued to be used for a few decades after the end of WWII, when USA had captured the German technology, because of their very high reliability, until the transistor amplifiers have become reliable enough.
The power from one loop is transferred into the other, there is no control. The same for two copper wires.
"Control" means that you can determine the value of the power in some circuit by consuming less power to do this. If you have to use the same power, not less, then you are the provider of power, not someone in control, i.e. this is the difference between bosses and the workers commanded by them. The bosses do not lift heavy parcels themselves, they order to some worker to do that.
A device that apparently looks like a transformer but it is an active device is the magnetic amplifier. There are 2 differences from a transformer, the magnetic core is saturable during normal operation (any magnetic core is saturable at a high enough magnetic field, but when that happens in a transformer this means that the transformer has failed, which leads to overcurrents that would destroy the equipment unless a protection is triggered), and the second difference is that the control coil has a very high number of turns, so that a very small current can saturate the magnetic core.
In a magnetic amplifier, the output coil is inserted in an AC circuit where the power must be controlled. When the core is not saturated, the impedance of the coil is high and the output AC current is low. When the core is saturated, the impedance of the coil is low and the output AC current is high. Whether the magnetic core is saturated or not is controlled with a very small current and power on the control coil, which makes this an active device.
Magnetic amplifiers have been heavily used during WWII, especially by the Germans, who had improved them, and they continued to be used for a few decades after the end of WWII, when USA had captured the German technology, because of their very high reliability, until the transistor amplifiers have become reliable enough.
> The current in one transformer loop does not control the current in the other loop.
You are right about the power, but the current in one loop __does__ control the current in the other loop.
You are right about the power, but the current in one loop __does__ control the current in the other loop.
We say a changing current in one coil of a transformer induces a current in the other coil. It does not control the current of the other coil.
Any induced current is superimposed on top of whatever is already there on the other side. This is different from controlling the current.
For example, you couldn't block DC current passing through the secondary side regardless what you did on the primary side.
Any induced current is superimposed on top of whatever is already there on the other side. This is different from controlling the current.
For example, you couldn't block DC current passing through the secondary side regardless what you did on the primary side.
Imagine i have a pencil which I'm holding in my hand. With my hand, I can control the position of the tip of the pencil. Now imagine the pencil is made of rubber. I can still control the position of the tip, but e.g. a strong wind can cause the pencil to flex and so the control is not perfect. But it is still control.
I don't see how this is fundamentally different from controlling the current through a transformer.
I don't see how this is fundamentally different from controlling the current through a transformer.
You use "control" in the wide sense of "dependency", i.e. if two quantities are constrained by an equation, you say that one quantity controls the other, only because their values are not independent (which means that fixing the value of anyone of the two quantities also determines the value of the other quantity).
According to your usage, the voltage on a resistor is controlled by its current, because the voltage is proportional with the current (by the resistance of the resistor), and also the current is controlled by the voltage, because the current is proportional with the voltage (by the conductance of the resistor), exactly like in a transformer the input and output currents and voltages are bound by proportionality relationships.
It is true that this meaning of "control" is encountered in speech, but in engineering and physics "control" has a precise meaning, more restricted that how you use it.
In the engineering use of "control", it is always possible to distinguish which is the controller and which is the controlled in a control relationship.
When "control" is used like you use it, the "control" relationship is bidirectional and you cannot say which is the controller and which is the controlled, e.g. between the primary loop and the secondary loop of the transformer, or between the current and the voltage through a resistor.
For "control" in the engineering sense, unidirectionality is an essential property. Real control devices have some internal feedbacks that make them not completely unidirectional, but this is considered a defect and serious efforts are done to improve the unidirectionality of the control devices. A device with total feedback like a transformer cannot be used to implement any of the known control methods, i.e. you cannot make amplifiers or oscillators or logic gates with it.
According to your usage, the voltage on a resistor is controlled by its current, because the voltage is proportional with the current (by the resistance of the resistor), and also the current is controlled by the voltage, because the current is proportional with the voltage (by the conductance of the resistor), exactly like in a transformer the input and output currents and voltages are bound by proportionality relationships.
It is true that this meaning of "control" is encountered in speech, but in engineering and physics "control" has a precise meaning, more restricted that how you use it.
In the engineering use of "control", it is always possible to distinguish which is the controller and which is the controlled in a control relationship.
When "control" is used like you use it, the "control" relationship is bidirectional and you cannot say which is the controller and which is the controlled, e.g. between the primary loop and the secondary loop of the transformer, or between the current and the voltage through a resistor.
For "control" in the engineering sense, unidirectionality is an essential property. Real control devices have some internal feedbacks that make them not completely unidirectional, but this is considered a defect and serious efforts are done to improve the unidirectionality of the control devices. A device with total feedback like a transformer cannot be used to implement any of the known control methods, i.e. you cannot make amplifiers or oscillators or logic gates with it.
But when electrical power is used to drive a simple DC motor, then that power "controls" the speed of that motor. When the power is removed and the motor keeps turning (by e.g. a flywheel) then the power is delivered back to the input. So in that example there is bidirectionality, where you still "control" the speed of the motor.
As I have said, some people, including you, are using the word "control" in this wider sense, where it is synonymous with "dependency".
Nevertheless, using "control" with this meaning in any engineering text would be a mistake, because there "control" must be used in its strict sense, to avoid confusions.
In any system there are many dependency relationships, corresponding to all the equations that are applicable to that system, but much fewer control relationships. The control relationships are quite important for the understanding of the system, so they must be identified clearly in a distinct way from other dependencies.
Etymologically, the right sense of "control" is the strict sense, because it has never been applied to a bidirectional relationship like that between the quantities connected by an equation, but it originally referred to a unidirectional relationship, between a dominant party, the controller, and a subordinate entity, the controlled, whose accounts were checked by the controller.
In proper engineering terms it is not the source of power which controls the speed of a motor, but the device that is used to vary the amount of that power. When there is no device to vary the input power, a DC motor works like a transformer, the input voltage is proportional with the output rotational speed and the input current is proportional with the output torque. The input quantities and the output quantities are dependent, so in the wide meaning of "control" you can say equally well that the input electric power is controlled by the output mechanical power or that the output mechanical power is controlled by the input electrical power. However the use of this phrases does not provide any advantage instead of just saying that you have a system of 2 equations that connect the 2 input quantities and the 2 output quantities, so given an appropriate pair of quantities the other 2 are provided by the equations. On the other hand, saying for instance that the motor speed can be controlled by the excitation current of the motor provides useful information by using the word "control", because it is implied that this method of varying the motor speed requires only a small power in comparison with the output power.
Nevertheless, using "control" with this meaning in any engineering text would be a mistake, because there "control" must be used in its strict sense, to avoid confusions.
In any system there are many dependency relationships, corresponding to all the equations that are applicable to that system, but much fewer control relationships. The control relationships are quite important for the understanding of the system, so they must be identified clearly in a distinct way from other dependencies.
Etymologically, the right sense of "control" is the strict sense, because it has never been applied to a bidirectional relationship like that between the quantities connected by an equation, but it originally referred to a unidirectional relationship, between a dominant party, the controller, and a subordinate entity, the controlled, whose accounts were checked by the controller.
In proper engineering terms it is not the source of power which controls the speed of a motor, but the device that is used to vary the amount of that power. When there is no device to vary the input power, a DC motor works like a transformer, the input voltage is proportional with the output rotational speed and the input current is proportional with the output torque. The input quantities and the output quantities are dependent, so in the wide meaning of "control" you can say equally well that the input electric power is controlled by the output mechanical power or that the output mechanical power is controlled by the input electrical power. However the use of this phrases does not provide any advantage instead of just saying that you have a system of 2 equations that connect the 2 input quantities and the 2 output quantities, so given an appropriate pair of quantities the other 2 are provided by the equations. On the other hand, saying for instance that the motor speed can be controlled by the excitation current of the motor provides useful information by using the word "control", because it is implied that this method of varying the motor speed requires only a small power in comparison with the output power.
But transformers don't do that.
The electricity you put in one winding "comes out" on an/the other, transformed -- there isn't one current controlling another, there's just one current[0].
[0] very loosely speaking, also I am not a doctor
[0] very loosely speaking, also I am not a doctor
> as active is taken to mean electrical control of current flow.
Does the building of logic gates controlling a motor not show electrical control of current flow?
Does the building of logic gates controlling a motor not show electrical control of current flow?
From https://news.ycombinator.com/item?id=40759133 :
> In addition to nanolithography and nanoassembly, there is 3d printing with graphene.
And conductive aerogels, and carbon nanotube production at scale
From https://news.ycombinator.com/item?id=41210021 :
> There's already conductive graphene 3d printing filament (and far less conductive graphene). Looks like 0.8ohm*cm may be the least resistive graphene filament available: https://www.google.com/search?q=graphene+3d+printer+filament...
> Are there yet CNT or Twisted SWCNT Twisted Single-Walled Carbon Nanotube substitutes for copper wiring?
Aren't there carbon nanotube superconducting cables?
Instead of copper, there are plastic waveguides
> In addition to nanolithography and nanoassembly, there is 3d printing with graphene.
And conductive aerogels, and carbon nanotube production at scale
From https://news.ycombinator.com/item?id=41210021 :
> There's already conductive graphene 3d printing filament (and far less conductive graphene). Looks like 0.8ohm*cm may be the least resistive graphene filament available: https://www.google.com/search?q=graphene+3d+printer+filament...
> Are there yet CNT or Twisted SWCNT Twisted Single-Walled Carbon Nanotube substitutes for copper wiring?
Aren't there carbon nanotube superconducting cables?
Instead of copper, there are plastic waveguides
Well, it is just “a step.”
Whether or not it is newsworthy… eh, I mean, what is MIT News? A campus newspaper? I’m pretty sure we had articles on particularly big games of capture the flag in mine.
Whether or not it is newsworthy… eh, I mean, what is MIT News? A campus newspaper? I’m pretty sure we had articles on particularly big games of capture the flag in mine.
What seems cool about this to me is that they seem to have done it with a plain old FDM printer and copper impregnated PLA. The devices are fairly large (mm scale) so presumably anyone with a $200 ender and the correct filament could print these.
I am able to find copper PLA for sale too, although I'm not positive it is what was used in the experiment, and it's kind of pricey (~ $100/kg).
I am able to find copper PLA for sale too, although I'm not positive it is what was used in the experiment, and it's kind of pricey (~ $100/kg).
It looks like the editors have amended the title of their article since this was initially posted. The original title was just “3D-printed Active Electronics”
usually even these academia hype pieces have some grain of utility but this one was so incomprehensibly bad that i was genuinely confused if i'm reading it incorrectly. what the hell?
Not to be that guy, but this is a typical situation as it occurs a thousand times per week:
1. Scientists make minor progress as part of a multi-year effort, release a paper, paper features overly optimistic outlook to get future funding
2. Institute marketing department both hypes it up and dumbs it down a little
3. Popular science press picks it up and both hypes it up and dumbs it down a little more
4. Scientific literate readers read it and complain
TL;DR: Nothing new under the sun
1. Scientists make minor progress as part of a multi-year effort, release a paper, paper features overly optimistic outlook to get future funding
2. Institute marketing department both hypes it up and dumbs it down a little
3. Popular science press picks it up and both hypes it up and dumbs it down a little more
4. Scientific literate readers read it and complain
TL;DR: Nothing new under the sun
> So no actual working active electronics.
Oh so this is another scam like the MIT Food Computer. At this point I assume everything coming out of MIT is a scam until independently validated by disinterested third parties
Oh so this is another scam like the MIT Food Computer. At this point I assume everything coming out of MIT is a scam until independently validated by disinterested third parties
This shouldn't be a downvote or flag. It's a serious problem, especially at elite institutions, and especially at MIT and Stanford.
It's also not out-of-line with what credible sources observe:
https://blogs.bmj.com/bmj/2021/07/05/time-to-assume-that-hea...
I'm affiliated with MIT, and have been for the vast majority of my life, including at points in fairly senior roles. If you shut people out pointing problems, it will never get better.
There's an incredible urge to defend elite academic institutions, but it's not in the interest of those institutions. Remember your civics class (patriots criticize their government institutions).
The only way I see this fixed involves a period where MIT is viewed like a used car salesman in the public eye for at least enough years to cause enough pain to lead to reform. The endowment is big enough it'll do fine in the end. If it keeps sliding to fraud, it won't.
It's also not out-of-line with what credible sources observe:
https://blogs.bmj.com/bmj/2021/07/05/time-to-assume-that-hea...
I'm affiliated with MIT, and have been for the vast majority of my life, including at points in fairly senior roles. If you shut people out pointing problems, it will never get better.
There's an incredible urge to defend elite academic institutions, but it's not in the interest of those institutions. Remember your civics class (patriots criticize their government institutions).
The only way I see this fixed involves a period where MIT is viewed like a used car salesman in the public eye for at least enough years to cause enough pain to lead to reform. The endowment is big enough it'll do fine in the end. If it keeps sliding to fraud, it won't.
I am a fan of 3D printing. And I think you can probably get some circuit traces 3D printed for some niche applications.
But active electronics? That's a huge stretch. But more importantly, the economics just doesn't make sense. Components already cost fractions of a cent. Small-run PCB prototyping is like <$25 for 5 boards or so.
"A step toward..."
Maybe. But why?
But active electronics? That's a huge stretch. But more importantly, the economics just doesn't make sense. Components already cost fractions of a cent. Small-run PCB prototyping is like <$25 for 5 boards or so.
"A step toward..."
Maybe. But why?
Being able to just print some simple electronics components would massively simplify iteration and distribution of DIY things, especially as auto-filament changer systems become more accessible. As one example, being able to print a transistor or two and some traces would allow for making projects which embed something like an ESP32 dev board much more compact without having to wait for weeks for custom PCBs to ship from China.
It's always weird to see people making arguments like this on a forum titled "Hacker News"
It's always weird to see people making arguments like this on a forum titled "Hacker News"
I think it is valid to point of feasibility of something. For fast prototyping there are already breadboards or PCBs that you can just solder wires on, so it doesn't really help with tracing PCB lines. Printing transistors or other things that are good and compact enough to use, even for prototyping, seems to be indeed a stretch
> would massively simplify iteration
I seriously doubt it.
It’s far easier and more effective (and economical) to have a bunch of jelly bean components around in stock.
You’re going to have a hard time 3D printing anything that can be solderable (either the 3D printer needs to work at high temperatures for DIY, or you need exotic solder that melts at low temperatures).
If you have the need to fabricate quick PCBs for prototyping, you’ll be better served by a cheap CNC machine and some copper foil blanks.
The only real promise I see is that you might, in the very long future, be able to print custom multi-purpose devices, that integrate the characteristics of non critical electronics with mechanical elements, i.e. integrating NTCs on cases or fan supports,..
I seriously doubt it.
It’s far easier and more effective (and economical) to have a bunch of jelly bean components around in stock.
You’re going to have a hard time 3D printing anything that can be solderable (either the 3D printer needs to work at high temperatures for DIY, or you need exotic solder that melts at low temperatures).
If you have the need to fabricate quick PCBs for prototyping, you’ll be better served by a cheap CNC machine and some copper foil blanks.
The only real promise I see is that you might, in the very long future, be able to print custom multi-purpose devices, that integrate the characteristics of non critical electronics with mechanical elements, i.e. integrating NTCs on cases or fan supports,..
in places where you have a 3d printer but you don't have an active shipping line that can easily reach you. You can easily prototype things or build electronics.
I also don't see this as the final result, printers could be purpose built for this to speed up production and make size smaller
I also don't see this as the final result, printers could be purpose built for this to speed up production and make size smaller
I suppose, but the 3D printer requires consumable inputs. So without active shipping that printer is going to have a very limited lifetime. There’s always a corner case, like having to 3D print on Mars or something, but thats a niche of a niche.
This is like posting "Landing on Mars" and all you did was catch a reusable rocket.
I think the "step towards being an inter planetary species" as a result of catching a re-usable rocket might have merit in that it makes construction of things in outer space easier (although that's probably a charitable interpretation of the statement).
My take on the Spacex is Mars habitation project is that Musk will put a bunch of edgelords on Mars, and then not really be able to follow up with adequate supply lines and the operation will be offline for a hundred years or so while the climate settles down. The people who live on Mars will then have been there alone for a century and in the 2100s we will send a follow up mission with hilarious consequences.
My take on the Spacex is Mars habitation project is that Musk will put a bunch of edgelords on Mars, and then not really be able to follow up with adequate supply lines and the operation will be offline for a hundred years or so while the climate settles down. The people who live on Mars will then have been there alone for a century and in the 2100s we will send a follow up mission with hilarious consequences.
Thunderf00t, is that you?
Haha I had never heard of that dude, but I like the look of his content thanks!
BTW you can tell I'm not Thunderf00t because he says that "the taxpayer" paid $3 billion. I would never use "taxpayer funding" language, I would only ever call it public money (because Treasury creates money when it spends).
BTW you can tell I'm not Thunderf00t because he says that "the taxpayer" paid $3 billion. I would never use "taxpayer funding" language, I would only ever call it public money (because Treasury creates money when it spends).
by that logic tax should be zero?
taxes are how you don't have inflation.
the government can also destroy money about as easily as it creates it, too. it isn't a politically (and usually economically) desirable thing to do. when it's done, it's usually via replacing the whole currency wholesale (e.g. brazilian real).
the government can also destroy money about as easily as it creates it, too. it isn't a politically (and usually economically) desirable thing to do. when it's done, it's usually via replacing the whole currency wholesale (e.g. brazilian real).
> taxes are how you don't have inflation.
or you know, don't print trillions to bail out failed banks.
or you know, don't print trillions to bail out failed banks.
Not really, if there was no tax there would be no money.
The most succinct way that I have found to express the relationship between taxation and spending is that spending at the federal level is constrained by aggregate spending this year, not tax receipts last year.
The most succinct way that I have found to express the relationship between taxation and spending is that spending at the federal level is constrained by aggregate spending this year, not tax receipts last year.
spending is constrained by whatever Congress says it is. the difference is borrowed.
It's logically impossible for a government to borrow the currency it issues. What we refer to as borrowing is just swapping one government liability (reserve balances) for another (treasury bonds).
you don't borrow from the present, you borrow from the future and hope to pay it back with growth
You don't need to be thunderfoot to understand that pretending you will start to colonize mars in the next years lies somewhere between daydreaming and scamming.
Although I like when thunderfoot compare the archives of what musk said with what actually happened
Although I like when thunderfoot compare the archives of what musk said with what actually happened
The punchline is that everyone here thought being called "thunderf00t" was a compliment, even though I meant it as an example of someone who is consistently proven wrong at every turn for casting shade on Musk's tech ambitions. It seems HN's original techno-optimist hacker ethos is dead in the grave.
Or is the REAL punchline the fact that Musk has optimised his entire empire to tap into the hacker ethos/ideals as the world's biggest pump n dump scheme? He seems to just do things that have the biggest wow factor because growth stocks need to keep growing otherwise there is no point in owning them.
He won’t put anyone living on Mars. And even if he did, they wouldn’t last that long.
https://defector.com/neither-elon-musk-nor-anybody-else-will...
https://www.acityonmars.com/
https://defector.com/neither-elon-musk-nor-anybody-else-will...
https://www.acityonmars.com/
That first article is just nonsense. The south pole can't support life? It's been supporting humans for half a century. Can't protect against radiation? Live underground like Hamas did. Have to wait 9 months for food? We do that on Earth too - if you're hungry, call a farmer and ask him to plant some food then come back in a year or two when it's harvested. We solve that problem by pipelining it, just as you would on Mars.
The South Pole hasn’t been “supporting humans”, we forced ourselves in there and survive despite the conditions in an environment that is harsh but even so considerably more hospitable than Mars.
All your other solutions are hand-wavey. Sure, let’s “just live underground” as if that’s just as easy as pitching a tent. And who on Earth is surviving nine months without any food? You’re talking as if Mars is just turning right on Albuquerque.
All your other solutions are hand-wavey. Sure, let’s “just live underground” as if that’s just as easy as pitching a tent. And who on Earth is surviving nine months without any food? You’re talking as if Mars is just turning right on Albuquerque.
Musk hasn't to my knowledge financed any architectural design projects for a long-term livable Mars habitat that can sustain itself without constant inputs from Earth.
I suspect this is because the most casual analysis reveals incredible difficulties - the structures would have to be buried under a few meters of regolith to avoid constant radiation burn, and the ration of human living space to plant growing space (for food) would have to be about 1:6 I'd guess. The amount of material required to build such a structure for 100 humans? Let alone maintenance, etc.
If realistic plans were actually presented no doubt everyone would start laughing, which is why we haven't seen any mock-ups, VR models, etc.
I suspect this is because the most casual analysis reveals incredible difficulties - the structures would have to be buried under a few meters of regolith to avoid constant radiation burn, and the ration of human living space to plant growing space (for food) would have to be about 1:6 I'd guess. The amount of material required to build such a structure for 100 humans? Let alone maintenance, etc.
If realistic plans were actually presented no doubt everyone would start laughing, which is why we haven't seen any mock-ups, VR models, etc.
They're working on getting the issue of transport sorted out first because the entire architecture is shaped by the constraints and requirements of your transport system. The amount of mass you can land, the energy needed for ISRU and so on.
HN just has forgotten its hacker roots and instead gets off to unconstructively sitting back and criticizing with shallow gotchas.
HN just has forgotten its hacker roots and instead gets off to unconstructively sitting back and criticizing with shallow gotchas.
"all you did was making rockets 10x cheaper", so you have plans for making them 100x to 1000x? That has nothing to do with Mars!
It's a step towards landing on Mars. They aren't even claiming to have landed.
Musk claimed we would be on Mars in 2022 so... https://www.theguardian.com/technology/2016/sep/27/elon-musk...
>"They saw an interesting phenomenon in the material they were using, a polymer filament doped with copper nanoparticles.
If they passed a
large amount of electric current into the material, it would exhibit a huge spike in resistance
but would return to its original level shortly after the current flow stopped."
This is interesting -- large amounts of current being associated with increased resistance...
I have never seen or read about something like that with respect to other electronic components or systems.
It would be an interesting experiment to see if this effect could be simulated, and if so, under what conditions, in non-nanoparticle standard regular-sized electrical components...
I'm guessing (but not knowing!) that you'd you'd need a very high amount of current (like something from a car battery), but at a very low voltage, like maybe 0.1 or 0.01 volts (or less), and maybe like a very thin long wire made of some mostly-conducitive material, and then maybe something at some scale or low voltage if the experimenter was lucky...
Anyway, large current associated with increased resistance... I've never heard of that one before, except I suppose if the current heats the electrical path so much that it destroys it... which would be different for different materials, voltages, cross-section of conductors, temperatures, etc., etc.
I'd assume that wouldn't happen at the nanoscale and/or in a switching semiconductor... but perhaps I might be wrong on some level...
If they passed a
large amount of electric current into the material, it would exhibit a huge spike in resistance
but would return to its original level shortly after the current flow stopped."
This is interesting -- large amounts of current being associated with increased resistance...
I have never seen or read about something like that with respect to other electronic components or systems.
It would be an interesting experiment to see if this effect could be simulated, and if so, under what conditions, in non-nanoparticle standard regular-sized electrical components...
I'm guessing (but not knowing!) that you'd you'd need a very high amount of current (like something from a car battery), but at a very low voltage, like maybe 0.1 or 0.01 volts (or less), and maybe like a very thin long wire made of some mostly-conducitive material, and then maybe something at some scale or low voltage if the experimenter was lucky...
Anyway, large current associated with increased resistance... I've never heard of that one before, except I suppose if the current heats the electrical path so much that it destroys it... which would be different for different materials, voltages, cross-section of conductors, temperatures, etc., etc.
I'd assume that wouldn't happen at the nanoscale and/or in a switching semiconductor... but perhaps I might be wrong on some level...
PTC (positive temperature coefficient) thermistors do that. https://en.wikipedia.org/wiki/Thermistor.
They’re used as auto-resetting fuses in many devices.
They’re used as auto-resetting fuses in many devices.
Interesting!
Did not know that before...
Excellent link!
Did not know that before...
Excellent link!
Lightbulbs? High amount of current increases resistance.
Excellent point!
(More broadly, a high amount of current through a wire in a vacuum tube, where the diameter of the wire is too small to carry all of the current without overheating in air, when placed in a vacuum tube, such as a lightbulb, will increase resistance with increased current (while turning part of the electricity into light/heat/radio waves/other forms of radiation, etc., etc.))
But, an excellent point!
(More broadly, a high amount of current through a wire in a vacuum tube, where the diameter of the wire is too small to carry all of the current without overheating in air, when placed in a vacuum tube, such as a lightbulb, will increase resistance with increased current (while turning part of the electricity into light/heat/radio waves/other forms of radiation, etc., etc.))
But, an excellent point!
large amount of electric current into the material, it would exhibit a huge spike in resistance
considering the low melting point of these 3d printing plastics, they probably melted the wire.
considering the low melting point of these 3d printing plastics, they probably melted the wire.
Long, long ago, Tunnel Diodes were going to usher in an era of ultra-fast computing because their negative resistance region allowed for current gain in the simple 2 pin device.
It didn't work out for most of it, but does show that you can do logic without transistors.
Think of these as incredibly slow negative resistance devices. Computing with them might be possible, barely. But sometimes that's all you need.
It didn't work out for most of it, but does show that you can do logic without transistors.
Think of these as incredibly slow negative resistance devices. Computing with them might be possible, barely. But sometimes that's all you need.
They arent dead!
Diy 8ghz (sampling) oscilloscope with tunneling diodes https://hackaday.io/project/167292-8-ghz-sampling-oscillosco...
Diy 8ghz (sampling) oscilloscope with tunneling diodes https://hackaday.io/project/167292-8-ghz-sampling-oscillosco...
I thought resettable fuses were already polymer based?
PPTCs are just plastic and metal with no semiconductors afaik
Is this actually an MIT article?
PPTCs are just plastic and metal with no semiconductors afaik
Is this actually an MIT article?
From the paper,
> This is, to the best of our knowledge, the first report of fully 3D-printed resettable fuses.
I think unique the contribution is that the entire circuit -- active and passive -- can be made with this one single material. Normally, you need to use many different materials and chemical baths to make a circuit with active components, but using this metal-polymer mix, you can _just_ deposit the metal and you are finished.
> This is, to the best of our knowledge, the first report of fully 3D-printed resettable fuses.
I think unique the contribution is that the entire circuit -- active and passive -- can be made with this one single material. Normally, you need to use many different materials and chemical baths to make a circuit with active components, but using this metal-polymer mix, you can _just_ deposit the metal and you are finished.
Oh my god. We might get real life redstone.
Also you may want to take a look at https://www.botfactory.co
Interesting idea but millimeter-scale logic doesn't really have much practical use in this day and age :) but it's s nice proof of concept.
Even placing traces inside a print and then slotting in IC boards would be useful.
Even at mm scale it changes the types of prints that can be done.
Even at mm scale it changes the types of prints that can be done.
This is fascinating. I did thing a while back if it was possible to 3D print primitive electronics.
While mentally stimulating, this sounds practically not very useful. They're using a copper-doped polymer for printing, which probably has way worse properties anything we make PCB traces out of.
And the 3D part is gimmicky. We have built electronic systems of monstrous complexity just with planar printers.
Wake me up when someone build a system that can reliably make PCBs at home, with placing components, and doesn't cost an arm and a leg, and is cheap and easy to run.
And the 3D part is gimmicky. We have built electronic systems of monstrous complexity just with planar printers.
Wake me up when someone build a system that can reliably make PCBs at home, with placing components, and doesn't cost an arm and a leg, and is cheap and easy to run.
It would be nice to pattern diodes and semiconductors on PCB without components as follows: etch circuit layout of a copper layer, mask the traces so they don't oxidize, then heat the PCB to have unmasked copper turn into Cu2O (cuprous oxide, a semiconductor).
Anyone seriously attempting this should make sure they understand solid state physics, and at a minimum understand diffusion length of charge carriers and the different type of contacts: Ohmic, Schottky ( for example https://lampz.tugraz.at/~hadley/psd/lectures20/contacts.pdf )
Performance will be horrible, but in some situations constructing and inspecting the device oneself can be paramount ( bootstrapping a secure computational platform, implementing formal verifier associated to a cryptocurrency, ... )
Anyone seriously attempting this should make sure they understand solid state physics, and at a minimum understand diffusion length of charge carriers and the different type of contacts: Ohmic, Schottky ( for example https://lampz.tugraz.at/~hadley/psd/lectures20/contacts.pdf )
Performance will be horrible, but in some situations constructing and inspecting the device oneself can be paramount ( bootstrapping a secure computational platform, implementing formal verifier associated to a cryptocurrency, ... )
Hmmm not sure I see the advantages of 3d printing vs lithography.
I mean, yes, technically, this approach could advance to catch up with lithography. In practice? Yes we are working toward smaller feature size in additive, but we are nowhere close to micro let alone nano scale.
If the advantage is "hobbyists can do it" then I would say "hobbyists can eaglecad too"
This seems like a detour or speedbump on our existing path toward atom level logic production.
I mean, yes, technically, this approach could advance to catch up with lithography. In practice? Yes we are working toward smaller feature size in additive, but we are nowhere close to micro let alone nano scale.
If the advantage is "hobbyists can do it" then I would say "hobbyists can eaglecad too"
This seems like a detour or speedbump on our existing path toward atom level logic production.
It's refreshing to see this labeled as a "step toward".
graycat(2)
And from the paper linked in the article[1], it seems the actual breakthrough is the discovery that copper-infused PLA filament exhibits a PTC-effect, which is noteworthy, but definitely not "3D-Printed Active Electronics" newsworthy.
[1] https://www.tandfonline.com/doi/full/10.1080/17452759.2024.2...