[HN Gopher] Show HN: We Made The World's Smallest and Cheapest N...
___________________________________________________________________
Show HN: We Made The World's Smallest and Cheapest Network Switch
Hello, we're Max and Byran from MUREX Robotics, a high school
robotics team from Exeter, New Hampshire. We are super proud to
have made this open source piece of technology! It is only 6.9
dollars (actually!) from JLCPCB :) I hope you like it. You can
find us at byran@mrx.ee and max@mrx.ee as well if you have any
questions. We will be putting a small run of these boards for sale
somewhere (we have <25 units of stock), probably for $10+shipping.
Let us know if you're interested in more! Board files for
everything we make is here:
https://github.com/murexrobotics/electrical-2024
Author : Hello9999901
Score : 549 points
Date : 2024-06-16 02:26 UTC (20 hours ago)
(HTM) web link (docs.murexrobotics.com)
(TXT) w3m dump (docs.murexrobotics.com)
| contingencies wrote:
| Nice job guys. For your next challenge, see if you can find a
| cost-effective way to add VLAN management, or do something cute
| with the form factor, like make it fit inside a standard
| electrical socket wall cavity with AC adaptor, or inside another
| ethernet port.
|
| PS. Try to reference vendor application notes or datasheets
| instead of stackexchange where possible.
| Hello9999901 wrote:
| Thank you! This goes in our underwater robot, and it has all
| the features that let the system work without anything else.
| However, we will definitely keep your suggestions in mind for
| our future revisions. We're seeing how to make this board even
| smaller, while keeping the cost down. 7 dollars (technically
| 6.9) is the mark to beat.
| bruce511 wrote:
| Well done.
|
| For those of us not generally in the hardware world (and thus not
| 100% familiar with the terminology) could you post more pics?
|
| Especially of the enclosure? I'm not really sure if you are just
| exposing headers, or if there are regular Ethernet plugs on the
| board?
| Hello9999901 wrote:
| Thank you so much! We're so happy you like it. It means a lot
| to us. We will be adding more pictures right now!
|
| We're exposing 1.25mm pitch Molex Picoblade connectors to make
| the board as small as possible. The built-in magnetics allow it
| to be connected to any Ethernet device just from spicing into
| an RJ45 connector.
| jakeogh wrote:
| Very cool. It says fully open source, are the board layout files
| available?
| Hello9999901 wrote:
| Yes! It is here:
| https://github.com/murexrobotics/electrical-2024 under
| networking/switch Edit: We use KiCAD Nightly 8.99 for the new
| features. You can view our boards easiest with kicanvas.org and
| just pasting in the
| https://github.com/murexrobotics/electrical-2024/tree/main/n...
| TZubiri wrote:
| Cool.
|
| Is this designed for personal or industrial use?
| ChillPill wrote:
| Hello, I'm Crane and I'm also on the MUREX Robotics team. The
| price point we are aiming towards is $7-$10. Our network switch
| is currently used for personal purposes, in our underwater
| robot, and we look forward to expanding it for industrial
| purposes.
| yonatan8070 wrote:
| Given the caseless PCB and non-RJ45 connectors, it looks like
| it's designed to be used on robots, and I can certainly see it
| being used that way in my robotics team
| toomuchtodo wrote:
| Excellent work, stay bold.
| Hello9999901 wrote:
| Thank you! It means a lot to our team!!
| jiveturkey wrote:
| hmm ... not the cheapest. $7 is just for the PCB (assembly)
| right? you need an enclosure and power supply as well.
|
| monoprice #41710 is $10 all in with a price break starting at qty
| 2.
|
| maybe you want to qualify your description with 'embeddable'.
|
| > built-in magnetics
|
| interesting b/c the website says `external magnetics`
| yonatan8070 wrote:
| Given this was made by a high school robotics team and it
| accepts up to 12V, it's likely that the intended use case is on
| a robot that already has a 12V battery
| Hello9999901 wrote:
| Hello! I just want to clarify some of these points. Saying it
| is the world's smallest switch is a bold claim, and there are
| definitely alternative options around. However, our board
| scales really well. The main reason we say it's the cheapest is
| because the real BOM is only around 4-5 dollars. Our small run
| of ~25 boards came out to ~$7 each. If you agree with my
| interpretation, perhaps the words "smallest and cheapest" can
| be together?
|
| Magnetics: We have built-in "external" magnetics, so the
| physical ports don't have the magnetic inductors required in
| the Ethernet standard. This makes the ports super small,
| allowing us to use 1.25mm pitch Molex Picoblade connectors.
| Again, thanks for the suggestions. We're still learning and the
| team is taking all the comments very seriously.
| fragmede wrote:
| The "real" BOM is what you can actually get. If you don't
| have the funding to make 10,000 boards in order to push to
| cost down to $4, then the BOM is $7.
| numpad0 wrote:
| Fast Ethernet +/- pins go through a special 1-turn transformer
| for electrical isolation installed between the PHY and RJ45
| connectors, commonly referred to as "the magnetics" in Ethernet
| world. It's physical ferrite and copper object molded like a
| chip, therefore it can't be trivially integrated into a silicon
| or in MCM. Hence most Ethernet chip require one _external to
| the chip_ , and in this case it is indeed external to the chip,
| and integrated into the board at the same time.
|
| (yes a cap in-line works too if you know what you're doing)
| Blammar wrote:
| Nice work indeed. However, was there a reason you didn't support
| gigabit ethernet? I haven't used 100mbit ethernet for more than a
| decade...
| aunver wrote:
| Hi! I'm Altan, another member of Murex. Many of the design
| decisions behind the switch were driven by the requirements of
| our underwater robot. In our case, the communication speed was
| capped by the transfer speed achieved over our tether (we use
| galvanically isolated OFDM to inject data over our powerlines).
| Since size and cost were our primary goals, 100mbit was more
| suitable than gigabit ethernet. While it would have been cooler
| to have a gigabit switch, it would also increase the size and
| cost.
| toast0 wrote:
| GigE needs twice the pin count. IMHO, there's not much room on
| the board for any more i/o. Certainly gigabit is nice, but
| there's plenty of applications where 100M is more than plenty.
| nativeit wrote:
| I'm not sure what your background is, but 100Mb Ethernet is
| still rather common in embedded devices and applications where
| the network protocol is primarily intended to facilitate UART
| serial communication. Just as a general note for context, I
| will defer to their more specific answer for this particular
| application.
|
| Neat project!
| procarch2019 wrote:
| Agreed. Due to the long lifecycle of manufacturing equipment
| we still see a lot of 100mb out there, and it's not even
| embedded.
|
| I would note that all new products seem to be gbe or better.
| jtriangle wrote:
| If you're doing tethered ROV stuff, the weight of the teather
| is a big big deal, so adding 4 additional wires is a non
| starter. For the stuff that goes extremely deep, they use fiber
| because it's much lighter. It presents significant cost
| increases of course, which, you'd want to avoid if you can.
| teruakohatu wrote:
| You can get neutrally buoyant cables:
|
| https://bluerobotics.com/store/cables-
| connectors/cables/fath...
| sgtnoodle wrote:
| It's still mass, drag and cost.
| jmb99 wrote:
| As much as modern Ethernet standards are much nicer (my house
| is wired for and running 10Gb everywhere, with 40Gb Infiniband
| to a couple locations too), 100Mbps still has its place.
| Specifically, anything embedded, slow, and/or cheap. No reason
| to spend the extra money on 4 more wires and pins and trace
| routing if your microcontroller only sends a few
| packets/second.
| liotier wrote:
| At that price point, the cost of the RJ-45 port is probably
| more than the cost of the 802.3 chip and I wonder if the cost
| of supporting that old chip on a contemporary device doesn't
| surpass the cost of the components for a nowadays standard 1
| GB/s.
| yonatan8070 wrote:
| This extremely cool, when I was in high school a few years ago we
| made some power adapter boards, but we couldn't have hoped to
| build a functional network switch, great job!
| ChillPill wrote:
| Hi, I'm Crane and I am also part of MUREX robotics and this is
| very inspiring to me as an electrical engineer who is starting
| out.
| spcebar wrote:
| Congratulations! Impressive work for any age.
|
| Is creating bespoke parts a requirement for your robotics
| competition or just a part of your team's ethos?
| Hello9999901 wrote:
| Our mission is to create open source electronics that
| democratize technology for as much people as possible! This is
| a full list of stuff we've done this year:
| https://www.murexrobotics.com/mrxEE. It isn't a requirement for
| the MATE ROV competition (I wish it was though; it would be
| super cool!).
| minetest2048 wrote:
| I wish we have this 2 years ago, this will be extremely useful
| for our cubesat. 115k2 baud UART is too slow for ground
| development
| ooochang wrote:
| Hello! I'm Osbert, another elec member on MUREX. For sure, we
| use 115k2 UART on our "custom" ESC serial communication
| protocol, MASCP (murex async serial communication protocol). We
| stream 2 IP cameras, our CM4 board (open source as well!), and
| our mrxPLC (DC powerline data injection technology). Thanks for
| the encouragement. It means a lot to our team!
| sr-latch wrote:
| Awesome work! It's really cool to see this from a high school
| team. While designing liquid rocket avionics [1] at Purdue Space
| Program, we went with a BotBlox switch that cost $80 apiece [2],
| which I thought was ridiculous. My proposal to in-house the
| Ethernet switch was vetoed because I was a filthy CS student
| (joke) and my co-lead (the electronics guy) said it wasn't worth
| our time designing and validating such a part.
|
| An Ethernet switch for $6.9 directly from JLCPCB is pretty
| incredible, thank you for making this product sector a tiny bit
| better :)
|
| [1] https://sagarpatil.me/projects/cms-avi-hw
|
| [2] https://botblox.io/products/micro-gigabit-ethernet-switch
| Hello9999901 wrote:
| "making this product sector a tiny bit better" is exactly what
| MUREX is all about :). It's something we honestly believe in
| and will continue working on as long as we're around. Believe
| it or not, the Ethernet Switch was the least problematic piece
| of hardware in our tech stack! If you want to take a look, we
| have our other boards in the docs as well. Your rocket is so
| f*ing cool as well! I definitely want to do something similar
| in college.
| sr-latch wrote:
| Ok this is sick, I love the philosophy of your team. I'll be
| strongly considering your CM4 carrier and ESC to integrate
| into future designs.
|
| Also thank you, I've loved working on the PSP rocket! Bi-
| propellant rocketry is a pretty rare to do as an
| undergraduate, and you should consider applying to these
| schools if that's something that motivates you:
|
| - Purdue: https://purdueseds.space/
|
| - Berkeley: https://www.berkeleyse.org/
|
| - UCLA: https://www.rocketproject.seas.ucla.edu/
|
| - Georgia Tech: https://www.gtspaceprogram.com/
|
| - ERAU: https://daytonabeach.erau.edu/about/labs/rocket-
| laboratory
|
| This is a non-exhaustive list of schools I know that have
| undergraduate-run liquid rocketry programs.
| knappe wrote:
| I'd add
|
| https://www.colorado.edu/studentgroups/cobra/
| tejtm wrote:
| and Portland State University!
|
| https://www.pdx.edu/psu-space#psas
|
| Undergrads, not catching on fire in space!
| Hello9999901 wrote:
| Thanks everyone! Noted deeply in the heart. :)
| minetest2048 wrote:
| I think you should submit your project page [1] as another show
| HN, I found it to be interesting
|
| Some thoughts:
|
| - Agreed with not using I2C, I2C has been identified as a root
| cause in several cubesat mission failures:
| https://pure.tudelft.nl/ws/portalfiles/portal/10531886/art_3...
| and
| https://webapps.unsworks.library.unsw.edu.au/fapi/datastream...
| (yes clock stretching is evil). I2C should be banned for multi
| board communication
|
| - Classic CAN have very small 8 byte MTU with frame preemption,
| which is actually useful for its intended purpose of time
| critical automotive data transfer. If that 4 byte brake packet
| is blocked by a 1500 byte packet then your car will crash and
| explode. But the tradeoff is that this makes it very slow for
| bulk data transfer
| RedShift1 wrote:
| Wtf, I2C in a satellite!? I am by no means an electrical
| engineer or know anything about doing stuff in space but it
| seems absolutely obvious to me if you require any sort of
| communication, that you use differential signaling. Even on
| earth you can have interference, in space with all its
| radiation it's guaranteed. I'm surprised anything worked at
| all with I2C.
| semi-extrinsic wrote:
| Yes, I2C is technically meant for intra-board use. But it
| works surprisingly well over large distances if you avoid
| daisy chaining and run one cable to each target. If you use
| multiple identical target chips you need to route
| everything individually to a central MUX anyways.
|
| As an example, the Nintendo Switch used I2C over a ~2m
| cable to communicate between the controller and nunchuck.
| Worked fine even in noisy household settings with wifi and
| microwaves and whatnot.
|
| At work we've used sensors for data logging that
| communicate using I2C over distances more than 20 meters,
| using plain Cat5 cable.
| TaylorAlexander wrote:
| Thanks for this! I recently designed a sensor board that
| connects to our main board with I2C, and in chatting with
| an EE about it she mentioned I2C is not intended for
| intra-board use. I just put a scope on the signals
| yesterday and they seem okay. The cable is only 15cm
| long, and it connects to a multi-use port which would be
| difficult to make work with differential signals in
| addition to the other things that port can do. I'll keep
| an eye on it but maybe it's okay.
| kenz0r wrote:
| If you _must_ use I2C, then look at SMBUS if its an
| option for the parts. I2C's biggest failing is that there
| is no protocol level timeout, so one stuck device can
| block your entire bus unless you have a reset line for
| all the peripherals on it.
| https://www.analog.com/en/resources/design-notes/guide-
| to-co...
| fl7305 wrote:
| Classic I2C problem. After your CPU resets, at least
| clock out a bunch of cycles onto I2C to get interrupted
| I2C transactions to finish.
| TaylorAlexander wrote:
| Ooh this is great to know thank you!
| crote wrote:
| I2C doesn't really care about cable length all that much.
| The thing to keep in mind is the interplay between bus
| capacitance, pullup strength, and drive strength.
|
| A longer cable means more bus capacitance, which means
| with the same pullup resistor the signal rise time will
| be higher, which means you need to reduce the bus speed.
| A stronger pullup will reduce the rise time (allowing a
| higher bus speed), but each chip's driver has to be able
| to overpower the pullup too. If the pullup is too strong
| for the drivers, you end up being unable to send a zero.
|
| In practice your cables can be quite long, you just have
| to run it at a lower speed. If you really want to push
| it, there's always transceivers like the PCA9615 which
| turn it into a differential bus.
| phero_cnstrcts wrote:
| Do you mean the Wii?
| semi-extrinsic wrote:
| Yes, of course I meant the Wii, sorry about the mix up.
| Too late to edit now.
| tinco wrote:
| Not an EE here, but I've dragged some circuits together
| as a hobby and have only used I2C. Why would Nintendo opt
| for I2C instead of a differential pair? Is there some
| extra part cost? What part(s) would you use to go from
| I2C to differential?
| joshvm wrote:
| I don't know about I2C specifically, but a related device
| is a serdes (serial-deseria) which converts between a
| parallel interface and one or more differential pairs.
|
| https://www.latticesemi.com/what-is-serdes
|
| Someone else mentioned the PCA9615 which looks like it'd
| to the job.
| semi-extrinsic wrote:
| I don't know why Nintendo did it. But it's certainly
| quite convenient, there are even standard form factor
| breakouts for the Nunchuck like in the link below. This
| gets you a controller with accelerometer, 2 buttons and a
| 2 axis joystick with plenty of libraries available for
| using it with Arduino, RPi etc.
|
| https://learn.adafruit.com/adafruit-wii-nunchuck-
| breakout-ad...
| znpy wrote:
| Worth noting though that the switch you linked claims to be a
| gigabit switch while the switch from murex is 100Mbpbs.
|
| Not sure if that justified the price difference
| wal5hy wrote:
| Congratulations MUREX Robotics team, great job!
|
| There are products at different price points on the market, for
| example this 55x55mm switch from my company Brainboxes[1] is
| sub $50. We choose that size so that we could also produce a
| gigabit option with the exact same footprint. We opted for
| microMatch[2] style connectors as you can get board to board as
| well as board to cable options.
|
| Your co-leads decision to buy-in is quite common, as you can
| reduce time to market and also not have to manage the component
| lifecycle if you go with an off the shelf option.
|
| [1] https://www.brainboxes.com/product/pure-embedded/pe-505
|
| [2] https://www.te.com/en/products/brands/micro-
| match.html?tab=p...
| Hello9999901 wrote:
| That's a sick board! If we had found that before we made it,
| maybe would have just used this board haha. What is "buy-in"?
| Is it meaning us using JLCPCB to buy and assemble the chips?
| wal5hy wrote:
| Thanks! Like yourselves we saw a clear niche for a ultra-
| reliable small embedded board suitable for robotics and
| other space constrained systems. I'd be very happy to send
| you one of our products to compare, i'll message your team
| email.
|
| By "buy-in" I was referring to the parent comment and how
| the electronics guy chose to buy-in a pre-made module
| rather than design their own.
| gardnr wrote:
| It looks great! Have you considered running it through
| https://www.quilter.ai/ before sending it out? It's free.
|
| You can hear more about it in this podcast:
| https://wandb.ai/site/resources/podcast/episodes/ai-in-elect...
| Hello9999901 wrote:
| I actually met with the Sergiy as well a few months back! Super
| cool guy. I also highly recommend quilter - thought it was
| super cool (not paid haha).
|
| Quilter doesn't have the best support for impedance matched
| traces. We do 90O on a 4 layer board and Bob Smith termination
| which has some pretty goofy design requirements.
| numpad0 wrote:
| Looks so cool! Just one question: IIUC, linear voltage regulators
| works by wasting voltage delta until target voltage is attained,
| instead of switching output current as buck converters do, so at
| 12V input it dissipates heat of up to (12-3.3)[V] * 0.8[A] =
| 6.96[W] onto the board depending on downstream current draw(of an
| FE switch, so I imagine would be tiny fractions of 0.8A
| realistically). Do board feel cool enough to touch as is?(please
| use back of hand/finger if unsure)
| Hello9999901 wrote:
| Hello, yes. Unfortunately it is hot to the touch. The board
| doesn't draw 800mA, but it does get to like 60C. Max, the main
| designer for V2, said a heatsink is recommended. Our thermal
| via solution keeps it within somewhat safe temps. We wanted to
| keep the cost low, so we opted for the LDO. In our robot we do
| direct 3.3V with a buck that does 3.3 for our entire system.
| That's Max's power board.
| quailfarmer wrote:
| Don't be afraid to implement a basic buck converter!
| Something like the MPQ4572 isn't too hard to get right (right
| enough for hobby projects at least).
| stavros wrote:
| They made an Ethernet board, I don't think a buck converter
| would be hard for them, but, as they said, it does increase
| the cost.
| stephen_g wrote:
| Honestly, hooking up a simple Ethernet switch IC is a
| cool project but isn't especially difficult - and this is
| only 100 Mbps also so not very tight tolerances.
|
| Set up your design rules right and I've had gigabit RGMII
| and 1000Base-X work first try.
| stavros wrote:
| Yes, if you're an expert at designing PCBs, I'm sure it's
| not hard. It's objectively hard, though.
| Hello9999901 wrote:
| For sure, this wasn't that hard. But I think that's
| great; it means anybody can be an EE. That's a core
| mission of our team. Our team works hard on PCIe 4.0, USB
| 3.1 Gen 1, and Gigabit ethernet as well. This is just one
| board that we made and were proud of. Feel free to take a
| look at our other boards in the documentation website!
| _zoltan_ wrote:
| how hard do you find pcie v4? did you look at how big a
| step is it to v5?
| tgtweak wrote:
| I would think the majority of people would be running this of
| of 3.7-4.2V lithium batteries or 5v USB so the step down
| Delta would be minimal, but yeah probably good advice to
| incorporate a more efficient buck step down for those running
| traditional 12v systems which usually operate at 14.4v.
| numpad0 wrote:
| Thanks - yeah 60C(140F) sounds somewhat warm, glad you're
| already planning for a DC-DC upstream. Feeding it 5V could
| make sense too(3.3V out + 1.2V dropout = 4.5V < 5V), but
| anyway this project feels like scratching an itch for many.
| Congratulations to you and your team!
| checker659 wrote:
| Are you telling me one does not need an EE degree to make
| hardware like this? How do high school folks have access to
| resources / mentorship to make such a polished product?
| Hello9999901 wrote:
| Absolutely not!! This is what MUREX is all about. We are on a
| mission to show anybody can do this. Change the world one small
| bit at a time. This was all self learned from the internet,
| trial and error, lots of passion, and this community. Our
| mentor doesn't have a background in engineering so he just
| gives us lots of emotional support and some physics help. Love
| you guys!! This is amazing.
| lostlogin wrote:
| I hope your mentor see this thread, they are doing a great
| job if your working anything to go by.
| Fordec wrote:
| Most major chipsets have their design specs in PDF format
| online with all the info there for interfacing on a hardware
| level. Many drivers these days are open source. Kicad is free
| to use for designing PCBs.
|
| And finally https://www.youtube.com/@PhilsLab has some good
| tutorials.
|
| Finally, goo into things with an attention to detail to polish
| a board. A hobby board takes far less time than a product
| board, but all it is is time and thinking about each attribute
| more. You don't need third level education to have that work
| ethic.
|
| Best of luck!
| ipqk wrote:
| This team is at the second best high school in the USA. they
| have the resources and the money.
| Hello9999901 wrote:
| Hello! We got 5k for the entire robot, and our school does
| not provide much engineering support. MUREX is entirely
| student run! Of course, we are incredibly thankful to be able
| to attend such a great school. we are first this year :)
| UnlockedSecrets wrote:
| I would love to have one of these, if still is available!
| Hello9999901 wrote:
| Please send us an email! We will try our best to get you geared
| up. byran@mrx.ee
| ChuckMcM wrote:
| This is truely awesome! Hat's off. If you're experience in
| college is anything like mine you will find that 90% of the
| incoming freshman class is looking at "electronics" for the first
| time (assuming you're going EE, but similar for CE or CS), you
| will be way ahead right from the start.
|
| That this switch is small and light might make for some
| interesting UAV applications as well!
| Hello9999901 wrote:
| Thank you so much! Super excited for college. I think it should
| fit right into an UAV. I see a lot of use from Ardupilot forums
| (which we use). It's the reason we have the LDO as well. We
| wanted to keep the application possibility open.
| iancmceachern wrote:
| This is awesome, you all rule
| Hello9999901 wrote:
| Thank you it truly means a lot to the team!!
| ojbyrne wrote:
| Typo: "commerically"
| Hello9999901 wrote:
| Thank you! Noted.
| fragmede wrote:
| > We will be putting a small run of these boards for sale
| somewhere
|
| Somewhere like http://tindie.com?
| Hello9999901 wrote:
| Maybe! If you'd like one, please email me at byran@mrx.ee!
| lanewinfield wrote:
| Hey can I just say I appreciate y'all's mission and energy in the
| comments? Very inspiring, very welcoming--you're the best!
| Hello9999901 wrote:
| Thank you so much! This energy has waked us all up!! We're all
| living together right now preparing for the world championships
| next week in TN! This is soooo exciting.
| banish-m4 wrote:
| Nice project and good work.
|
| The only thing is it doesn't address a new or existing market as-
| is because it competes with what already exists. For example, a
| TrendNet 10/100 compact switch (not a hub) goes for $7.31
| including shipping on eBay and it comes with a case and a power
| supply. Decommodifying a product requires finding niches where
| there is demand like automotive, aerospace, military, or marine
| applications. Until roughly 2020, 2.88 MB 3.5" floppy drives were
| in-use primarily in industrial and turnkey commercial systems
| long after they disappeared from desktop computers. Dinosaur
| technologies can live on for a very long time, often in critical
| systems deemed too expensive to replace.
|
| Keep pushing forward, learning, and getting better.
|
| Btw, if someone made a:
|
| - 48 port 10GBASE-T (802.3an-2006) POE++ (IEEE 802.3bt-2018)
| 960W-1600W+ (3422W would be the upper limit for type 4)
|
| - L2 (at least) switch
|
| - unmanaged to fully-managed (but no cloud features)
|
| - 4 100GBASE QSFP28 uplinks (unpopulated)
|
| - dual, hot-swappable PSUs
|
| - 2 models: Ports facing either forward or reverse
|
| - 19" 1U half rack depth, and wall mountable
|
| - _Most importantly:_ doesn 't sound like a jet engine under full
| load by leveraging better engineering, such as using some
| industrial-rated parts, heatpipes, and moving hotter air but less
| volume
|
| I'd throw down in the $6K price-point neighborhood.
|
| Comparables:
|
| $4800 FS S5860-48XMG-U is close but sounds like a jet engine with
| dual 1U screaming PSUs and 3 hot swap chassis fans, but only
| available in conventional top-of-rack forward facing, leading to
| longer, messier wire management unnecessarily.
| userbinator wrote:
| _For example, a TrendNet 10 /100 compact switch (not a hub)
| goes for $7.31 including shipping on eBay and it comes with a
| case and a power supply_
|
| A 1G switch from Ali with a case, power supply, _and the RJ45
| connectors_ is also under $10.
| numpad0 wrote:
| This isn't a desktop Ethernet switch. Lots of robotic parts
| like industrial cameras and fancy laser sensors use Ethernet
| for interfacing instead of USB or RS232C. Doing so solves cable
| length limitations and connection stability issues of those
| peripheral buses. There would be penalties and overheads of
| (mis?)using inter-node communication protocols like Ethernet
| (and TCP/IP), but those tradeoffs are completely acceptable.
|
| What is not acceptable is full sized switches inside of a
| robot: they're way too bulky. You may be looking into
| installing a switch inside a humanoid upper arm or inside
| pelvis. Regular switches and hubs don't fit there.
|
| This product solves that specific robotics packaging problem.
| Electrically it's a switch/hub, physically it's much smaller
| than that, that's the point.
| globular-toast wrote:
| I wonder if you could do away with the switch and just daisy
| chain in many of those applications. It seems to be forgotten
| that ethernet supports this.
| varjag wrote:
| It's not exactly forgotten. There's 2 wire Ethernet/PoE
| standard (used mostly in automotive) that can be daisy-
| chained. Designing for it however is non-trivial and few
| third party devices (again outside automotive market)
| support it.
| globular-toast wrote:
| Hmm... I thought everything still had collision detection
| and would work on a bus, like what you'd get using a hub.
| varjag wrote:
| There is normally no collision detection beyond 10Mbps.
| Also PoE would not trivially work daisy chained.
| toast0 wrote:
| 100base-Tx is specified for shared media (hub rather than
| switch), but I think you need some electronics to make a
| hub, you can't just do a passive connection, and so you
| probably end up with a hub IC and may as well use a
| switch IC instead.
| sgtnoodle wrote:
| It might work in so far as you'll get packets through.
| The performance would be abysmal, though. Modern Ethernet
| is built around switching.
| globular-toast wrote:
| Would it really be that bad? If the devices were well
| behaved (ie. not too noisy, no gratuitous ARP etc) and
| the application could assume that most of the time either
| zero or no devices will be communicating, would it be
| that bad?
|
| This is something I might test myself. I have a couple of
| audio devices that will never be both "active" at the
| same time. In my current layout I need to run either two
| cables or just another switch and it just seems a waste.
| I wonder if I can buy daisy chained cable so I don't have
| to make one...
| wal5hy wrote:
| Our company is often asked at expos if we supply 2 wire
| ethernet switches (e.g. Single Pair Ethernet SPE[1]) but
| the reality is there's little demand (outside of
| automotive) we see in the Industrial marketplace for this
| type of product.
|
| The other issue is that there is at least 2 competing
| industrial connector standards for SPE, the main ones
| being from Harting[2] and Phoenix Contact[3]. I think
| this could be a great option for the future and
| ultimately lead to lower cost cabling and smaller
| products.
|
| [1] https://www.single-pair-ethernet.com/en
|
| [2] https://images.app.goo.gl/ND9d9x66YNUckS7g6
|
| [3] https://images.app.goo.gl/yWAiUAx4Y5vRmmbZA
| varjag wrote:
| Yeah that's the thing: neither of them is really
| standard, and both are fairly expensive. They are also
| available in very limited mechanical configurations
| (angle, mounting). Fortunately SPE does not really
| require either of them. In our product we're going with
| our own solution.
| lostlogin wrote:
| > Our company is often asked at expos if we supply 2 wire
| ethernet switches (e.g. Single Pair Ethernet SPE[1]) but
| the reality is there's little demand
|
| This reminds me of a funny conversation I had in a small
| town stationers when looking for an item.
|
| 'No, we don't stock it. People keep asking, and I keep
| having to explain that there is no demand.'
|
| Though this wasn't for an obscure Ethernet variant.
| wal5hy wrote:
| ha, true! However at expos often the person asking is a
| vendor looking to sell SPE components to us, or someone
| in the industry trying to determine if a technology is
| popular. Can be a bit of an echo chamber.
| p_l wrote:
| In industrial IO, including robotics, the norm these days
| is 3 port switches embedded into devices, specifically to
| support daisy chaining.
|
| Hubs are no-no because of various performance issues,
| including how more and more gear supports gigabit on the
| daisy chaining.
| gertrunde wrote:
| I suspect the combination of being able to dissipate 3.4kW of
| power, and the requested size and noise constraints may put
| this combination of features firmly beyond reasonable, even
| before considering cost.
|
| But there is always room to hope. :)
| crote wrote:
| A PoE-supplying switch doesn't need to _dissipate_ that
| power. Assuming a power supply efficiency of 85%, supplying
| 3400W to downstream devices means having to dissipate 600W of
| heat.
|
| Keep in mind that you'd be supplying 71W to every single
| downstream port. That's an insane amount of power. Something
| like a Cisco Catalyst 9136I Access Point only comes up to
| 47W, and that's assuming 16 radios, double 5Gbit uplinks, and
| a USB device drawing 9W.
| mike_d wrote:
| A Juniper EX4100 ticks all your boxes.
|
| Adding a sound requirement is stupid and ridiculous. You're
| wanting to take the power supplies from 48 90W devices and put
| them all in one dense little box and then complaining that it
| needs to be cool.
|
| If you have room for 48 PoE devices, you have room for a
| properly cooled and sound isoloated IDF.
| chx wrote:
| If you are interested in such things, check botblox. They have a
| similar sized switch, a smaller one with fewer ports, a stacked
| one for Gigabit... it's very expensive though.
| xamuil wrote:
| Ah you're right -- the team and I were not aware of BotBlox's
| 3-port switch! I guess a more specific description would be the
| world's smallest 5-port unmanaged switch. We do however beat
| BotBlox's similar 5-port unmanaged switch [1] slightly in size
| and miles in cost. I'm Max by the way, the lead designer of
| this revision.
|
| [1] https://botblox.io/products/small-ethernet-switch
| cliftonk wrote:
| j/c but why are we still maxing out at 1gb ethernet connections?
| why have the speeds essentially not progressed in 20 years? you
| can get a 40gb connection by just using usb-c on modern machines.
| what's going on? (curious about why this is the case industry-
| wide, i think this project is really cool)
| MrMid wrote:
| The intended use-case for this board is some robotics
| applications. I don't think parts of robots need to communicate
| via gigabit. 10/100 Base-T is presumably easier to implement
| and thus cheaper and smaller (which is the point of this
| project)
| wtallis wrote:
| You can get 40+ Gb/s over USB-C or connections like DisplayPort
| and HDMI by using thick expensive cables that top out around
| 10ft of length. Beyond that, price starts shooting up as you
| get either optical transceivers or active retimers/redrivers
| built into the cable assembly.
|
| Ethernet over copper is designed for cable runs of over 300ft
| and has to be much more forgiving of poor quality cables and
| connectors. That means for the same level of complexity and
| power consumption in the transceivers, you're just not going to
| be able to get as much bandwidth.
|
| Ethernet equipment suitable for 2.5Gb/s and 5Gb/s in consumer
| equipment (cheap, low power) is now readily available, but
| there's not enough demand to drive pricing down to parity with
| 1GbE and completely supplant it. 1GbE is _good enough_ for most
| consumer use cases, especially given the dearth of multi-Gig
| WAN connections in the consumer market, the lack of popular use
| cases that would benefit from slightly faster LAN connections,
| and the continuing improvements to WiFi.
| Hikikomori wrote:
| 2.5gbit is quite common and cheap.
| stephen_g wrote:
| Combination of power and distance.
|
| Copper Ethernet standards tend to be specified for over 30
| metres, and go (preferably) up to 100m. That's pretty tricky to
| do, you need quite thick cable with individually foil shielded
| pairs to achieve those kind of long distances at 10Gbps. 40
| Gbps USB-C on the other hand is recommended to travel over a
| _maximum_ of a metre or so of cable, with the recommended being
| 0.8m (2.6ft) of cable or less! Thunderbolt cables that go
| longer need active driver chips inside the cable in each
| connector to make the whole thing work.
|
| Then there is the power issue, 10Gbps Ethernet uses
| significantly more than 1Gbps, so a 40GBase-T switch would be
| even more power hungry.
|
| The combination of these has meant that basically most people
| just use fibre if they need more bandwidth.
| rgovostes wrote:
| The comparable BotBlox SwitchBlox Nano is 25.50 x 25.50 mm,
| albeit with two fewer ports. This is 44.90 x 42.11 mm. How do you
| justify the claim of being the world's smallest?
| xamuil wrote:
| Hi, I'm Max, the lead designer of this V2 revision. You're
| absolutely correct! My team and I were not aware of BotBlox's
| 3-port switch, so a more specific description would be the
| world's smallest 5-port unmanaged switch. The smallest
| commercial alternative we found was also BotBlox's 5-port
| unmanaged switch [1], which we beat in both size and cost.
|
| Once again, our mission is to create open-source, cost-
| effective, and accessible electronics for as many people as
| possible -- I think our board is much more attractive in that
| respect and a win in my book :)
|
| [1] https://botblox.io/products/small-ethernet-switch
| mike_d wrote:
| Since you have thrown ISO/IEC 8877 out the window, which is
| referenced by 100BASE-TX, you surely can't call it an
| "ethernet switch."
| advael wrote:
| This is amazing, well done, no notes, would love to buy when
| available
|
| I think it's been rightly pointed out that you aren't beating
| commodity parts on price, but you're also not a manufacturing
| operation with scale and there is a certain niche for which
| anything with open hardware that's well-documented is a killer
| feature
| Hello9999901 wrote:
| Please email us at byran@mrx.ee for now!
| jeffrallen wrote:
| > full Bob-Smith style termination for all center taps
|
| Man, that's some serious inside baseball right there.
| Hello9999901 wrote:
| Thanks! Do it right, do it MUREX!
| tarasglek wrote:
| Not a hardware guy,how does one crimp and secure those custom
| ends?
| Hello9999901 wrote:
| You can buy them right of Digikey by searching "4 position
| Molex Picoblade cable assemblies" or similar!
| schobi wrote:
| It is great to see that this is accessible and possible with
| limited effort/budget!
|
| On the higher speeds, it remains difficult: In the datacenter,
| 10G ethernet is often standard or even outdated. But for non-
| mains powered systems, even 10G uplink is hard to come by. I
| would love to have a switch with 25/100G uplinks in a smaller-
| than-19"-rack form factor with 12-40V DC power. Building one as a
| side project might still be too complex - if you would get access
| to chipsets at all.
| Hello9999901 wrote:
| We only found ~gigabit and ~fast ethernet chipsets that are
| easily accessible. However, it's definitely something we will
| think about in the future! Thanks for the suggestion!
| crote wrote:
| How about the Mikrotik CRS510-8XS-2XQ-IN? 2x 100G uplink,
| 8x25G/10G/1G downlink, DC power input, and only 320mm (12.5in)
| wide.
| jpc0 wrote:
| Some details I would like to see:
|
| - Does the backplane support full 1.25Gbps throughput?
|
| - Does is switch at line rate for all packet size?
|
| - The switch chip supports LACP, port mirroring, vlan tagging,
| QOS, these would be amazing to integrate into a product even for
| slightly higher cost in a 5 port switch
|
| - It's generally a hard requirement for me the 801.3az be off by
| default or can be turned off. I've had far too many issue with it
| enabled on network
| Hello9999901 wrote:
| Hello! It supports 100Mb throughput, nothing more, nothing
| less. It's been tested with iperf. I believe it switches at
| line rate, but don't quote me on that haha. The chip's extra
| features can be enabled with an EEPROM, which we removed to cut
| costs and size further. It's on V1 though.
| auselen wrote:
| Congrats.
|
| A few months ago I wanted to make a small lab out of a few SBCs.
| Looking for a cheap 10/100 switch, I was surprised to see prices
| are this low; got a tplink 8 port / LS1008 for 10$ from Amazon.
| Hello9999901 wrote:
| Thank you! We also have those switches. They are fantastic
| cheap tech as well.
| rbanffy wrote:
| One side project I never seem to start is a single board cluster
| based on Octavo SoMs. The idea is to have 32 cores per board to
| mimic a Thinking Machines CM-1-like cube. How easy is it to use a
| PCB to route Ethernet between nodes? What kind of components
| would go between the SoM and the switch?
| Hello9999901 wrote:
| That would be super cool! I'm not sure how it'd work together.
| I would think we need a higher speed fabric-type connection.
| zokier wrote:
| Why classic full-fat fast-ethernet (base-tx) instead of single-
| pair ethernet (base-t1 or t1l/t1s) if you are targeting embedded
| use?
| Hello9999901 wrote:
| Thanks for asking! That is a very good question. However, we
| use bog-standard Ethernet connections, so using Fast Ethernet
| is super straight forward. Just splice the cable and we're all
| good.
| moffkalast wrote:
| > It is only 6.9 dollars
|
| > probably for $10+shipping
|
| You could honestly sell it for $30-40 and it would still be a
| pretty good deal. Meanwhile Blue Robotics be like "that'll be
| $175 plus $50 shipping and customs fees as a percentage of that
| $175 fam"
|
| https://bluerobotics.com/store/comm-control-power/tether-int...
|
| God, everything they sell is overpriced to the point of insanity.
| They could really use some proper competition.
| numpad0 wrote:
| Low volume hardware pricing always look infuriatingly high, but
| they also start looking hopelessly low once you've dipped toes
| into it and tried multiplying your _spent_ development man-
| hours with McDonalds wages or tolerable unit price by expected
| sales volume.
|
| I've never heard of Blue Robotics, but I doubt that $175
| product ships 1k units/year, and even if they did, that's $170k
| revenue, or 2x entry level engineers salary worth of raw
| recovered cash _before factoring in any expenditure whatsoever_
| , let alone taxes and HR. It probably hardly feeds one, and
| that's based on an optimistic hypotheticals that they ship a
| thousand of that product every year.
|
| Large scale multinational corporations ship in orders of
| million units. That makes it way easier to amortize non-
| recurring engineering and ship small products virtually at
| cost.
| moffkalast wrote:
| I mean sure, I understand that. But that doesn't mean I have
| to like it. BR are really well known to anyone dealing with
| ROVs or AUVs, but that's not exactly the average person.
|
| Commercial consumer hardware R&D is mostly a fool's errand
| these days, since if it's something that's worth producing
| and sells there will be clones that work just as well
| available almost immediately. I'm not sure how say, Adafruit,
| sells anything at all to be honest, anything they make gets
| perfectly cloned and sold on Aliexpress for a tenth of the
| price. I guess going extremely niche and overpriced is one
| way to work around it.
| bhouston wrote:
| Great work!
| Hello9999901 wrote:
| Thank you!
| StephenSmith wrote:
| Now do POE
| Hello9999901 wrote:
| That's one area we are exploring!
| FredPret wrote:
| Your group is incredibly cool, keep it up. It's exciting that
| kids in high school have access to this type of activity. I love
| living in the future!
| Hello9999901 wrote:
| Thank you! Attempt the impossible :)
| allenrb wrote:
| Seriously, my high school was mostly boring and pointless. I'm
| in awe of the opportunities some kids are able to find/create
| today.
| tgtweak wrote:
| Can you make a 2.5g version
| Hello9999901 wrote:
| Unfortunately, it's not really useful for our use-case. Our
| robot only uses ~kB amount bandwidth.
| teddy__d wrote:
| impossible is now possible
| Hello9999901 wrote:
| unleashing innovation :o
| OrvalWintermute wrote:
| Can you produce a 10Gb version of the same?
| AstroJetson wrote:
| Nice job, I'm always impressed with HS robotics projects. Clever
| design and nice form factor.
|
| I bought a stack of these:
|
| https://www.amazon.com/Tenda-Gigabit-Unmanaged-Wall-Mount-Pr...
|
| for some projects that need ethernet. They are mid-level quality.
| Not sure I'd put them on something that would break my heart to
| get back.
| Hello9999901 wrote:
| I agree. They're also so much larger than our design! If
| getting a switch ever interests you, please let us know at
| byran@mrx.ee. No pressure of course!
| voidmain0001 wrote:
| "We are super proud to have made this open source piece of
| technology" - of course it's open source - you live in the state
| of "Live free or die!" My favourite state motto. Thanks!
| xhrpost wrote:
| Sorry if I missed it on the page but are all the ports Auto-MDIX?
| Hello9999901 wrote:
| We didn't try, but I think so. We always ensured the crossovers
| were correct. Sorry I can't give a better answer!
___________________________________________________________________
(page generated 2024-06-16 23:00 UTC)