[HN Gopher] A deep dive into Single Pair Ethernet
___________________________________________________________________
A deep dive into Single Pair Ethernet
Author : killcoder
Score : 155 points
Date : 2023-09-01 14:17 UTC (8 hours ago)
(HTM) web link (electricui.com)
(TXT) w3m dump (electricui.com)
| throw0101a wrote:
| 802.3cy recently added support for 25 Gb/s:
|
| > _In addition to the more computer-oriented two and four-pair
| variants, the 10BASE-T1,[20] 100BASE-T1[21] and 1000BASE-T1[22]
| single-pair Ethernet physical layers are intended for industrial
| and automotive applications[23] or as optional data channels in
| other interconnect applications.[24] The single pair operates at
| full duplex and has a maximum reach of 15 m or 49 ft (100BASE-T1,
| 1000BASE-T1 link segment type A) or up to 40 m or 130 ft
| (1000BASE-T1 link segment type B) with up to four in-line
| connectors. Both physical layers require a balanced twisted pair
| with an impedance of 100 O. The cable must be capable of
| transmitting 600 MHz for 1000BASE-T1 and 66 MHz for 100BASE-T1.
| 2.5 Gb /s, 5 Gb/s, and 10 Gb/s over a 15 m single pair is
| standardized in 802.3ch-2020.[25] In June 2023, 802.3cy added 25
| Gb/s speeds at lengths up to 11 m.[26]_
|
| * https://en.wikipedia.org/wiki/Ethernet_over_twisted_pair#Sin...
|
| 802.3dg is going for 100M and 1000M over distances of 500m
| LinuxBender wrote:
| Are there any consumer devices supporting 802.3dg? The reason I
| ask is that I often push the limits of current gigabit ethernet
| distances and have found that actual limits are much shorter
| than theoretical limits _meaning some network cards have a hard
| time negotiating at full speed and often fall back to 100mb
| unless forced_
| throw0101b wrote:
| > _The reason I ask is that I often push the limits of
| current gigabit ethernet distances and have found that actual
| limits are much shorter than theoretical limits_
|
| Get a cable tester and see what the cable type/qualtiy and
| signal characteristics are. Or if you're near some other
| equipment that is high-EM (where shielding may be needed).
|
| There is nothing theoretical about the official numbers with
| a quality install:
|
| * https://en.wikipedia.org/wiki/Ethernet_over_twisted_pair#Va
| r...
|
| In the ISO/IEC structural cabling standard the length is
| strictly informative, and the length of a cable/run doesn't
| matter as long as the signal characteristics are good: you
| can have a 130m run and a tester will not pass-fail based on
| the length, but on the signal quality:
|
| * https://www.youtube.com/watch?v=kNa_IdfivKs&t=12m32s
| LinuxBender wrote:
| I just have a cheap tester. I've been contemplating getting
| a better one that can do signal testing. Maybe this is a
| good excuse to get one.
| ilyt wrote:
| > The reason I ask is that I often push the limits of current
| gigabit ethernet distances and have found that actual limits
| are much shorter than theoretical limits meaning some network
| cards have a hard time negotiating at full speed and often
| fall back to 100mb unless forced
|
| Does it have problems on single unbroken cable like that or
| it just has few patch-panels along the way ? IIRC the
| standard was for 100m unbroken cable, not the usual of device
| -> cable -> patchpanel -> cable ->patchpanel -> cable ->
| patchpanel -> cable -> device
| throw0101b wrote:
| The TIA structured cabling standard assumes
| patch(5m)+run(90m)+patch(5m):
|
| * https://www.youtube.com/watch?v=kNa_IdfivKs&t=11m48s
|
| * https://www.truecable.com/blogs/cable-academy/maximum-
| ethern...
|
| With the ISO standard the length is strictly informative,
| and the length of a cable/run doesn't matter as long as the
| signal characteristics are good:
|
| * https://www.youtube.com/watch?v=kNa_IdfivKs&t=12m32s
| LinuxBender wrote:
| Just over 120m _400 ft preformed_ firewall to firewall
| _between two houses_. Sometimes it works better if I turn
| off EEE. I 've tried a few models of firewalls/nics _all
| mini-pc 's, all Intel_. I think I'm just slightly over the
| rated length. Using buriable cat-7 in a conduit meant for
| fiber. _Had the conduit run by the same people that
| installed the fiber._
| jwiz wrote:
| I'm sure you considered it, but fiber might fit this
| application better?
|
| Also, AIUI, having the electrical isolation between the 2
| buildings is nice.
| LinuxBender wrote:
| Fiber would be better. I've indeed contemplated it and
| may end up going that route.
| throw0101a wrote:
| > _Are there any consumer devices supporting 802.3dg?_
|
| Given that it's not even ratified yet... no.
| killcoder wrote:
| We built a Power over Data Line (PoDL) compliant device and power
| supply as part of a one-month 'sink or swim' approach to
| designing and testing new hardware, and getting to look at
| maturity of the 10Base-T1 ecosystem. The board was enclosed a
| submersible sensor node and field tested at a popular dive reef,
| SCUBA diving down and mounting it to the jetty.
|
| It was also a nice excuse to get some macro shots of the PCB
| assembly process, including some nice footage of solder paste
| melting and the interesting surface tension interactions.
|
| (I can't seem to get the videos to render in a format that iOS
| Safari will play, if anyone knows the ffmpeg incantation, please
| let me know, nothing I've tried has worked on my iPhone...)
| maaarghk wrote:
| my shell history has this in it, but it might have been for
| android firefox ~ `-c:v vp8 -b:v 2000k -pix_fmt yuv420p`
| Timon3 wrote:
| Might I suggest using an ffmpeg frontend like HandBrake? It has
| a bunch of presets, the Apple ones will surely work for this.
| fanf2 wrote:
| Interesting write-up with some very nice pictures!
|
| The videos worked for me on my iPhone. Always nice to see a bit
| of solder reflow :-)
| doctorpangloss wrote:
| The amount of expertise that went into this 1 month project is
| crazy and it's all really cool and well put together.
|
| I don't comprehend how you made no mistakes on the journey
| after drafting the PCBs and writing drivers. From my POV as a
| software developer, C has so many pitfalls that it is
| incomprehensible to me that things will Just Work, especially
| in the context of something that is meant to run for a very
| long time and not be "restarted."
|
| Why do sensor things at all? What is the ROI for the person who
| needs that stuff? I mean this in no derogatory sense, I really
| admire this work.
|
| But the academics who need something something hardware are
| either so rich they use something commercial / the paid core or
| so poor they'll use someone else's refuse or a grad student to
| do it 10x worse & 10x slower for free. Lab equipment, sensors,
| whatever.
|
| If it's for an industrial purpose, the ultimate consumer for
| hardware 2 guys can make is the government, as far as the eye
| can see. Like the people who have a business stake in e.g. the
| ocean ecosystem are fishermen, oil people, shippers, whatever,
| and they're _only_ doing this because of a government
| regulation or threat thereof or whatever. I view government
| needs as worthwhile, they are a worthy customer, it 's that the
| ROI is essentially imaginary, it's whatever the payer values
| government compliance and that can be infinitely large or
| small.
|
| My background in this is very limited, I didn't take "How to
| Make," I don't know how to use anything in a fablab, but in an
| intellectually honest way, the audience for "polished, well
| working gizmo with bug-free firmware" is 1,000,000x larger when
| it's a coffee machine than any academic or industrial purpose.
| Why not make "the perfect espresso machine" or "the perfect
| bike" or whatever? There are $3m Kickstarters for coffee
| machines whose #1 actual obstacle to successful execution is
| writing firmware. There are e-bikes that are 10x expensive or
| 10x crappier because ultimately it's too challenging to make a
| single firmware and controller to make disparate commodity
| parts work together cohesively.
|
| I am not at all raining on this parade, because this little
| blog post was so mind numbingly impressive; and I'm not saying
| there aren't 10,000 people toiling on dead-on-arrival consumer
| hardware, be it Oculus peripherals or connected emotive robots
| or whole divisions at Google. My question is: why? Why not,
| with your skills, make a thing and fucking sell it?
| lelanthran wrote:
| > I don't comprehend how you made no mistakes on the journey
| after drafting the PCBs and writing drivers. From my POV as a
| software developer, C has so many pitfalls that it is
| incomprehensible to me that things will Just Work, especially
| in the context of something that is meant to run for a very
| long time and not be "restarted."
|
| Process, design and architecture play a larger role in the
| bugcount than language choice.
|
| I wrote munitions control software in C; many of the systems
| that would cause loss of human life were written in C _for
| decades_.
|
| The recent meme of "if it's written in C it must mean
| unreliable" is inaccurate - all the most reliable systems,
| for decades, were written in C.
| jacoblambda wrote:
| Not OP but
|
| > I don't comprehend how you made no mistakes on the journey
| after drafting the PCBs and writing drivers. From my POV as a
| software developer, C has so many pitfalls that it is
| incomprehensible to me that things will Just Work, especially
| in the context of something that is meant to run for a very
| long time and not be "restarted."
|
| You aren't meant to make no mistakes, just only make
| recoverable mistakes. In a lot of cases you can rely on your
| hardware for this. Watchdog Timers are specifically intended
| for this. You set up a watchdog when you deploy the device
| and your software has to periodically "pet" the watchdog or
| the system triggers some action. In practice this is used to
| verify that the software never gets stuck or else it triggers
| a recovery/restart sequence and maybe sends out an alert. The
| end goal shouldn't be bug free but "even with bugs it
| eventually recovers and keeps working unless the hardware
| physically dies".
|
| > Why do sensor things at all? What is the ROI for the person
| who needs that stuff? I mean this in no derogatory sense, I
| really admire this work.
|
| Once again not the OP but I could see this being useful. They
| are recording wave patterns on or around a reef. That could
| be used for modelling how reefs can buffer water conditions
| (ex: for the purpose of constructing man made analogues) or
| as part of a greater sensor suite for documenting how
| "weather" impacts reef ecosystems.
|
| And you would want a system you can deploy and leave
| unattended for long periods of time since every trip out
| costs money and depending on what you are specifically
| researching, simply returning to the site could interfere
| with/disrupt the experiment.
| h2odragon wrote:
| > Single Pair Ethernet supports long range >1km cable runs
|
| That's going to introduce a lot of people to the joys of outdoor
| long wires and their interaction with lighting. I've seen the
| induction current from ground surge turn 25 pair cat3 into
| _vapor_ ... there 's fun to be had there.
| FfejL wrote:
| Lighting? Or lightning? I'm hoping the latter!
| lostlogin wrote:
| Surely lightning.
|
| I'm in New Zealand and our sun just destroys everything. The
| UV eats everything up and I'd not expose a cable to sunlight.
|
| Plenty of places are hotter or have more UV but also have air
| pollution which blocks UV. Our relatively clear air lets the
| UV come ripping through.
|
| At least sunlight won't toast my switch though.
| sgt wrote:
| Is this why NZ streets, roads, towns generally look a bit
| "tired"? Hard to explain what I mean, but if UV light fades
| all the colors and makes things look neglected, it would be
| one explanation.
| lostlogin wrote:
| New concrete or even clean concrete is actually hard to
| be near and squinting is the norm. The difference just so
| striking when I go to Europe - it's like soft focus has
| been applied.
| organsnyder wrote:
| When I was a kid my family owned the (dumpy) neighboring house
| and used it for my dad's office. I ran cat5 between them, and
| it worked fairly well--except for one time when four ports
| (including the one feeding that line) of one of the switches
| blew out after a lightning strike.
|
| For my own outbuilding office (above our detached garage), I
| ran fiber to avoid this issue.
| mschuster91 wrote:
| Or with wildlife. Moles, mice, rats, rabbits, if your cable is
| not shielded with solid metal it will get eaten through.
|
| Other common issue with novices running outdoor cabling are
| people running belowground cables strung outdoors on poles in
| the open air - UV degradation can take such cables (or rather,
| their insulation) apart in a matter of less than a year. Or
| silicone cables that end up in stagnant water, which can
| dissolve them (don't ask me about specifics, but it's a hotbed
| of issues in PV power plants). Or people not burying their
| cables deep enough, i.e. below the frost line, and the ground
| freezing over killing the cables.
|
| Outdoor wiring is fun for everyone involved. If anyone here
| wants to deal with that crap, please read up on using the
| correct cable for the job, and FFS have a certified electrician
| sign off on the grounding of such cables and surge arrestor
| designs and installation.
| peterleiser wrote:
| I worried about all of these things before installing 8
| outdoor security cameras using PoE. The system is in a rural
| area with lots of critters and 100+ degree summers. I used
| direct burial & outdoor cabling but left it above ground and
| in some cases strung from pole to pole. It's been 3 years and
| the only issue was 2 cameras shorted at the "waterproof"
| Ethernet jack connector on the camera.
|
| This was not mission critical so I just "went for it" and it
| worked out. It was a great payoff since it only took 2 days
| to mount all the cameras and lay the cables. It would have
| taken much longer to dig trenches and put the cables in
| buried pipes. I treated it like a prototype and figured I
| would improve later based on actual problems that came up.
|
| I did make sure all of the boxes with wire connections, power
| supplies, and PoE switches were in waterproof boxes and I
| used silicone sealer where cables entered the boxes. I opened
| up one box yesterday and not even a cobweb!
| mmastrac wrote:
| > 2 cameras shorted at the "waterproof" Ethernet jack
| connector on the camera.
|
| Let me guess: unifi. I love em but I have two dead cameras
| because I assumed outdoor meant outdoor.
| LinuxBender wrote:
| For me it was yellow bellied marmots. They got into the
| ceiling. Now everything is in thick conduits. I learned my
| lesson for cutting corners ... and having to clean up all
| their little _gifts_.
| ilyt wrote:
| Yeah at that distance I'd just say fuck it and pay extra for
| fiber.
|
| I guess ability to power via same cable is an advantage here vs
| having to still have separate wire (or say local solar+battery
| for sensor).
| selectodude wrote:
| Fiber isn't really all that much extra anymore. Duplex
| single-mode fiber is like 1/3rd the cost per meter as Cat6a.
| It's more expensive at the margins (optics, switches) but if
| you want to go 10gb, it ends up being a wash. And fiber will
| get you up to 400G+ if you ever want it without new cables.
| mschuster91 wrote:
| The biggest cost saving in fiber is in the lightning strike
| case. Assuming the power lines are properly grounded and
| surge arrestors appropriately installed, at least a strike
| won't fry your expensive switch or even more of your
| infrastructure.
| [deleted]
| imhoguy wrote:
| And this rabbit hole thread has brought me to Power-over-
| Fiber solutions.
| Dylan16807 wrote:
| Also, since this doesn't really talk about the ethernet data, the
| signalling for 10Base-T1L is PAM3, 4B3T, 7.5 megabaud. So 4 bits
| of data get turned into 3 symbols, each symbol being either
| negative voltage, positive voltage, or zero voltage, and then the
| symbols are transmitted at 7.5MHz.
|
| Something to note is that it has a much lower bandwidth
| requirement than 10BASE-T, because 10BASE-T uses manchester
| encoding with two symbols per bit (either 01 or 10). So 3.75MHz
| of bandwidth versus 10MHz of bandwidth.
| inamberclad wrote:
| I just started a job using PoDL and so far I'm quite impressed
| with it as a technology. I'd like to see consumer devices start
| to use it too.
| myself248 wrote:
| But there are several types of ethernet that run over a single
| pair now. There's 802.3bu, 802.3cg, 802.3da, 802.3bw, and
| possibly more.
|
| And I can't tell if any of them are compatible. I think da is
| compatible with cg, but the others are all little islands, all
| serving very similar needs in mutually-frustrating ways.
|
| Whyyyyyyyyyyyyyyyyyyy?
| coder543 wrote:
| This is nowhere near as confusing as you're making it out to
| be. - 802.3bu specifies PoDL (power over data
| lines). - 802.3bp specifies 1000Mb/s over SPE (single
| pair ethernet) - 802.3bw specifies 100Mb/s over SPE
| - 802.3cg specifies 10Mb/s over SPE - 802.3da is an
| enhancement of 802.3cg.
|
| In fact, you've had most of this explained to you before[0],
| including your long "whyyyyyy".
|
| Modern WiFi has a very long list of 802.11 standards attached
| to it... My WiFi access point supports _all of these_ :
| - 802.11a - 802.11b - 802.11g - 802.11n
| - 802.11ac - 802.11ax
|
| I rarely hear anyone complain about the alphabet soup involved
| there, but relatively recently, they've been rebranding it as
| WiFi 5, WiFi 6, WiFi 7 since it is something consumers run into
| more frequently than things like SPE.
|
| SPE is _not_ intended for home users. The SPE standards are
| designed to make things easier for automotive and industrial
| applications, and they seem fine. Automotive needs are not the
| same as industrial needs, so flexibility in the standards
| allows them to meet the specific needs of each application
| better. It also allows them to remove unnecessary weight and
| complexity. Weight reduction is one of the main reasons
| automotive is interested in SPE.
|
| SPE has no obvious advantages for home users over something
| like Monoprice's Micro SlimRun cables, which are extremely thin
| and flexible, for example. So, it makes sense that they haven't
| put effort into giving it cool branding like "WiFi 7".
|
| [0]: https://news.ycombinator.com/item?id=35074023
| ilyt wrote:
| > SPE is not intended for home users.
|
| Seems plenty useful if you could actually buy that stuff for
| the home-user-tolerable pricing.
|
| Connecting _and_ powering 4 different devices over single
| ethernet cable is a very nice use case for various sensors.
|
| Hell, even for IoT, ethernet/IP is pretty simple protocol
| compared to BT stack, wifi+ip, or zigbee, just plug in and
| power your sensor/switch/relay with 2 wires directly into
| local ethernet network, no bridges needed, and pretty safe
| too vs any radio.
| Dylan16807 wrote:
| > Connecting and powering 4 different devices over single
| ethernet cable is a very nice use case for various sensors.
|
| If you have multiple clusters of devices, I can see that.
|
| But in most cases I feel like a bunch of thin cables will
| be significantly less hassle than trying to split things.
| ilyt wrote:
| If you're dragging cables sure, but you might have _a_
| ethernet cable already in place.
|
| Currently option is to get a PoE-powered switch and split
| it off that way which is extra device to manage.
| MayeulC wrote:
| I feel like SPE has a lot of potential for IoT, sensors,
| etc. Well, maybe some cheap PLC could compete too, but
| the multi-drop and PoDL capabilities are quite
| interesting for dispatching a few $3 sensors.
|
| I kind of want to run SPE over old coaxial cables that
| are quite commonly found in relatively recent houses. Add
| a cheap ESP with I2S, an I2S DAC and a speaker, and you
| get a smart multi-room speaker setup.
| addaon wrote:
| > SPE has no obvious advantages for home users over something
| like Monoprice's Micro SlimRun cables, which are extremely
| thin and flexible, for example.
|
| PoDL does have real advantages over PoE. I agree that there's
| no home-user-ready products at this point, but I could see
| future exploration of this space for that reason alone.
| coder543 wrote:
| > PoDL does have real advantages over PoE.
|
| I'm curious, what advantages are you thinking of? PoE++ can
| deliver more power than PoDL, last I checked.
|
| I guess the option for lower voltage could be nice in some
| very specific applications? I think the minimum for PoDL in
| the spec is 12V, which would still require conversion for
| pretty much any use case.
| addaon wrote:
| PoDL and PoE are both limited to SELV (< 60 V) for safety
| reasons, so no win there. On paper, PoE can handle more
| current; but PoE current is limited by center-tapped
| transformers, which tend to overheat if you push too far.
| Just due to the ease of getting a wider range of
| inductors, it's pretty easy to build PoDL systems that go
| up to wire current capabilities; and SPE runs better than
| you'd expect for tens of meters over some ridiculous
| high-gauge wire, since it really is tolerant of out-of-
| spec wiring. 5A - 10 A (300 W - 600 W) over a, let's say,
| "PoDL-inspired" system is quite achievable.
| coder543 wrote:
| As far as I know, the PoDL spec tops out at around 50W,
| but you could be right that a "PoDL-inspired" system
| (which I found amusing) could potentially go much higher
| than that.
| addaon wrote:
| Yeah. Basically PoE forces a common coupling (center-
| tapped transformer) for both power and data, which really
| limits not just part availability but also the design
| space. While the PoDL inductive power coupling and
| capacitive data coupling interact (and pin capacitance of
| the inductor can be an issue with really big inductors),
| they're near-independence really, really opens the design
| space up.
| aeyes wrote:
| > SPE has no obvious advantages for home users over something
| like
|
| It does, I already have a single twisted pair running in the
| walls of a building where it is hard to run new cables but I
| can't get more than 100Mb/s at the moment.
|
| Using existing wiring is always a use case, a lot of people
| use MoCA or PLC because they can't run new cables for
| whatever reason.
|
| But as you said, unfortunately SPE is strictly for industrial
| applications at the moment and there is no affordable product
| for consumers.
| wolrah wrote:
| > It does, I already have a single twisted pair running in
| the walls of a building where it is hard to run new cables
| but I can't get more than 100Mb/s at the moment.
|
| The 100mbit and gigabit variants of SPE require higher
| grade cabling than their multi-pair counterparts.
| 1000BaseT1 requires Cat6A, which would normally be needed
| for 10 gigabit. It is very unlikely that you have a single
| pair of Cat6A grade wiring available, or that anyone does
| anywhere.
|
| They're not really for reusing existing wiring, they're for
| reducing wire count in new harnesses in automotive,
| aerospace, and other applications where size/lightness
| matters.
|
| The 10 mbit SPE varieties on the other hand, those are more
| closely targeted at reusing existing wiring, but they mean
| the sort of wiring that might have previously carried CAN
| or other common control bus.
| wolrah wrote:
| > Whyyyyyyyyyyyyyyyyyyy?
|
| Because they're built for different roles with different
| requirements, but in all cases are expected to be used for
| specialized applications.
|
| The 10 megabit SPE varieties are mostly intended to be able to
| be used on existing wiring in commercial/industrial
| applications where older hardware is being upgraded but
| replacing existing wiring might not be practical. The two
| varieties let you pick between long distances (10BaseT1L) or
| the ability to connect multiple devices to a single network
| segment like old school coax ethernet (10BaseT1S). There are
| also use cases for the short range variant internal to
| machines, where it can in many cases run over the same harness
| one might have run CAN over.
|
| The 100 megabit and gigabit variants don't care about existing
| wiring, they're there to move a lot of data over as few wires
| as possible so harnesses can be light, thin, flexible, cheap,
| take your pick. Automotive infotainment and high bandwidth
| industrial sensors are the obvious target markets.
|
| You aren't expected to ever need to mix and match between these
| variants. While more than one could plausibly be found in the
| same system it'd be rare for there to be any need to mix and
| match hardware between the different forms. If they need to
| talk to each other you stick a bridge/switch between them the
| same way you would have when transitioning from coax to twisted
| pair ethernet.
| addaon wrote:
| Two things I've learned working with SPE in its 100 Mb and 1 Gb
| configurations for a few years:
|
| 1) PoDL is substantially lighter, smaller, and simpler (though
| not necessarily cheaper) at 1 Gb than at 100 Mb, due to the
| increased frequency separation. Just like with other Ethernet
| protocols, the lowest frequency of comms is basically DC; it's
| only statistically brought above that by the scrambler, but
| there's no useful true lower bound. Having an order of magnitude
| more separation, such as it is, allows a more reasonably sized
| filter to stomp over less (ideally, approximately none) of the
| data.
|
| 2) Only the 1 Gb protocol includes FEC, 100 Mb is a simpler, non-
| error-correcting encoding. This means that even though the
| maximum frequency on the twisted pair goes up by an order of
| magnitude to ~660 MHz, requiring better cabling, better twist
| spacing, etc... it allows a "sloppier" job at both high and low
| frequencies, since the FEC really does hide a few errors. This
| can be spent on even worse filters for PoDL, on frequency-
| specific interference (e.g. an RF amp running nearby), etc.
|
| Basically, I was surprised to find that 1 Gb was not only not
| more challenging at the system design level, it was often
| simpler. (I haven't played with 10 Mb in either of its two
| incarnations seriously yet.)
| wmf wrote:
| PoDL = Power over Data Line. I guess this is similar but
| incompatible to PoE.
| addaon wrote:
| Similar in purpose, extremely different in implementation,
| since PoE-supporting Ethernets (e.g. 100base-TX) are
| magnetically coupled, but PoDL-supporting Ethernets (e.g.
| 100base-T1) are capacitively coupled.
| monocasa wrote:
| I mean, isolation transformers like in regular amd PoE
| Ethernet are a form of capacitive coupling.
| gumby wrote:
| > PoDL is substantially lighter, smaller, and simpler (though
| not necessarily cheaper) at 1 Gb than at 100 Mb,
|
| This was one of those wonderful "oh of course" points for me:
| when you read something and it's blindingly obvious, but until
| reading it my intuition pointed the other way (easier to deal
| with lower frequencies rather than unnecessarily high data
| rates).
| madengr wrote:
| [dead]
| TrueDuality wrote:
| Great write up. Looks like the GitHub repo with the project
| hasn't been posted yet. Look forward to poking through that!
| joezydeco wrote:
| Agreed. This writeup is _beautiful_. And I learned a bunch
| about SPE in the meantime.
| scohesc wrote:
| As a side project I'm looking at making an autonomous vehicle of
| some kind, starting with a ground vehicle and eventually moving
| to something on or under the water.
|
| It's mindboggling how many different ways there are to
| communicate with microcontrollers, sensors, etc. So many
| different standards with different data rates, capabilities,
| features, etc.
|
| It's cool to see something like ethernet be able to be used in
| rough situations like this. I'm sure this is done already with
| some technology, but I'd love to see a buoy with solar/wind and
| batteries for power, with a tether going down into the water to
| supply power and data for sensor arrays underwater. Trying to
| communicate through water is tough - I even looked at acoustic
| modems to try and transfer data but it looks like they haven't
| gotten down to consumer/tinkerer level of electronics yet.
|
| Single Pair ethernet with power seems very complicated for a
| fairly ignorant but interested hobbyist haha
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