[HN Gopher] Raspberry Pi KVMs Compared: TinyPilot and Pi-KVM v3
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Raspberry Pi KVMs Compared: TinyPilot and Pi-KVM v3
Author : arantius
Score : 87 points
Date : 2021-09-22 17:45 UTC (5 hours ago)
(HTM) web link (www.jeffgeerling.com)
(TXT) w3m dump (www.jeffgeerling.com)
| mdevaev wrote:
| PiKVM v3 HAT on Kickstarter right now.
| https://www.kickstarter.com/projects/mdevaev/pikvm-v3-hat
|
| // I'm the author ;)
| geerlingguy wrote:
| Thanks for sending me the prototype to test; besides the
| labeling issue, and the fact that I accidentally fried one of
| the fan power cables (thought I'd burnt up the whole unit!)
| when I first put it together, it's already a great product. I
| hope you sell many more thousands, and keep improving the
| experience!
| mdevaev wrote:
| No problem! I'm glad for constructive comments, it will help
| v3 to become better. I hope PiKVM will be useful to you.
| dihydro wrote:
| I just backed your project because of this video. I can't wait
| to get my hands on it and give it a try.
| mdevaev wrote:
| Thanks! I'm sure you'll like it.
| mongol wrote:
| It says PiKVM has support to press power buttons etc. Does PC
| hardware also have means for health checks, to determine if
| this is needed? Could be a useful feature
| mdevaev wrote:
| This is done by reading the status of the power LED of the
| PC.
| gruez wrote:
| What's the latency like on these? Almost imperceptible? I find
| that the delays on VNC/RDP are noticeable enough to be annoying,
| even on LAN.
| geerlingguy wrote:
| In my testing and my Dad's, about 100-300ms. Very noticeable,
| but you kinda get used to it.
|
| You can get it down to sub-100ms using a few hacks, but
| honestly, this kind of setup is not optimal if you need remote
| real-time control (e.g. for gaming or video production
| monitoring).
| marwatk wrote:
| What are the hacks? I use a Pi-KVM and the latency is
| painful.
| mtlynch wrote:
| TinyPilot founder here.
|
| Happy to answer any questions about TinyPilot or KVM over IPs.
| ActorNightly wrote:
| General microcontroller questions if you don't mind.
|
| Lets say that I prototype something on dev board like something
| from Raspberry Pi, or ones from STM. Now I want to do a full
| product, (like the Tiny Pilot) with the microprocessor on a
| custom PCB board with just the necessary hardware.
|
| I understand that you have to design the schematic and then get
| the PCB layout done, but in terms of figuring out which pins to
| connect, is it just a matter of figuring it out from the
| microcontroller manual? Additionally, how do you end up
| programming the microcontrollers, do you have to have a
| separate programmer since you don't have all the stuff on the
| dev board?
| zokier wrote:
| > Lets say that I prototype something on dev board like
| something from Raspberry Pi, or ones from STM.
|
| Worth noting that your typical STM32 MCU is quite different
| class of device compared to the Broadcom SoC on a RPi. From a
| architectural point of view, the big difference is that MCUs
| typically have both flash and ram integrated in the package,
| while SoC requires external ram and flash. Designing PCB for
| high-speed DDR memory is not trivial. Modern SoCs come in
| high-density BGA packages usually sporting close to thousand
| pins (or more!), while MCUs usually come in more easy to work
| with packages with order of magnitude less pins.
|
| Specifically the Broadcom chip in current RPis is custom made
| and not generally available.
| mtlynch wrote:
| TinyPilot runs on the Raspberry Pi 4B, so I haven't made my
| own custom board yet.
|
| The Voyager 2 will use custom PCBs for the HAT, but it will
| still be on top of the Pi.
|
| In the next iteration, I'd like to use the Pi Compute Module
| to migrate to my own custom board, but I'll need to work with
| an EE firm on that, since I'm not knowledgeable enough about
| EE for that kind of project.
| mdevaev wrote:
| By the way, does Voyager 2 have its own CSI bridge, or are
| you planning to mount a ready-made module from Geekworm or
| another company next to your HAT?
|
| All existing CSI bridges that you have used so far have two
| very serious problems: they do not work with audio capture
| and due to HDMI backpowering, your Raspberry may stop
| booting until you physically disconnect the cable.
| Backpowering is especially common when using KVM switches
| and some HDMI converters.
|
| Both of these problems are solved on v3 HAT, thanks to our
| CSI bridge design. Are you planning to solve these
| problems? Just interesting :)
| mtlynch wrote:
| Voyager 2 uses the C779 bridge. I've heard of failure to
| boot when users chain TinyPilot to the AIMOS KVM, but
| I've never gotten reports of this being a problem
| otherwise.
|
| There's no audio support, and audio would be a nice-to-
| have, but it's not my top priority at the moment.
|
| I'd like to integrate the TC358743 onto the HAT itself,
| but Toshiba's got a huge lead time on orders right now.
| myelin wrote:
| Yep! It's a matter of figuring it out from the
| microcontroller manual / datasheet (or basing your design on
| one that already has it figured out.)
|
| Programming microcontrollers is done using an in-circuit
| programmer, which connects to a header on the board. Adafruit
| has a great tutorial for this:
| https://learn.adafruit.com/proper-step-debugging-
| atsamd21-ar...
| simcop2387 wrote:
| > is it just a matter of figuring it out from the
| microcontroller manual?
|
| pretty much, you might end up tweaking which pins you use
| when designing the pcb because the one on the other side of
| the chip is just as good, but it simplifies the routing and
| layout of the board significantly.
| aberoham wrote:
| When might you add the ATX feature?
|
| And do you listen to any of these Covenant Network radio
| stations that are now under TinyPilot's control?
| mtlynch wrote:
| > _When might you add the ATX feature?_
|
| I started work on that earlier this year, but I paused it to
| focus on PoE. That work is almost done, so I should be able
| to revisit ATX early next year.
|
| The challenge is more on the UX side. It's not that hard to
| connect the Pi's GPIO pins to a motherboard's ATX pins, but I
| want to do it in a way so that it minimizes the amount of
| nitty-gritty pin-matching that the user has to do to connect
| it correctly.
|
| > _And do you listen to any of these Covenant Network radio
| stations that are now under TinyPilot's control?_
|
| I don't think they'll reach me out here in Massachusetts, but
| if I'm in the midwest, I'll check 'em out.
| mike-the-mikado wrote:
| In all this, I've not seen any mention of what "KVM" means...
| geerlingguy wrote:
| Good to note--I should at least in the video have a little text
| overlay that shows 'KVM = Keyboard Video Mouse'. You forget
| sometimes how acronym-laden our industry is, and even the ones
| you find most basic... better to spell it out for someone who
| might not operate in the same area.
| sneak wrote:
| Keyboard Video Mouse. It's a device for receiving video output
| from a computer and providing keyboard and mouse input from a
| remote operator.
| jldugger wrote:
| "Keyboard, Video, Mouse" is what the acronym means for anyone
| wondering. Some IT workers will have one at their desk to
| switch a single set of monitors, keyboards and mice between
| multiple computers.
|
| In this context, however, there's an additional expectation
| that these devices make this happen over a network, so that you
| can handle things like BIOS configuration fully remotely.
| deckard1 wrote:
| > so that you can handle things like BIOS configuration fully
| remotely.
|
| Yeah, the important distinction here is that these devices
| somewhat fulfill the role of a standalone IPMI[1] device.
| IPMI is typically built into server motherboard (SuperMicro)
| which allows an administrator to reboot a machine or
| configure BIOS over a network. Your typical KVM does not
| feature this.
|
| However, where these lack is that they still require a video
| card. IPMI built into a motherboard can run on an entirely
| headless system.
|
| There are also commercial versions of this, such as the
| Lantronix Spider KVM over IP[2]
|
| [1] https://en.wikipedia.org/wiki/Intelligent_Platform_Manage
| men...
|
| [2] https://www.lantronix.com/products/lantronix-spider/
| louwrentius wrote:
| Maybe for some context - although Jeff Geerling does provide it
| too in his video - most 'server' motherboards have build-in KVM.
|
| I will make the bet that build-in KVM is more responsive and
| those interfaces are now HTML5 based, so no nasty Java applet
| stuff.
|
| Motherboards / servers with KVM will consume around 8-10 watt
| extra, even when powered off, as the KVM solution is basically a
| tiny computer running Linux + proprietary software, soldered on
| the motherboard.
|
| Motherboards with KVM support also support IPMI or redfish for
| remote management. For instance: I use IPMI to force a physical
| machine to PXE-boot into an automated installer, to provision the
| OS.
| nh2 wrote:
| For some more context why such a device is desirable:
|
| Mainboard-built-in KVMs provided by server vendors are usually
| buggy as hell closed-source horrors, with regular full-
| compromise holes that make running them over the Internet a
| complete gamble.
|
| This is why open-source KVMs that are just as secure as other
| normal Linux servers, and auto-upgradable, are very desirable.
| whalesalad wrote:
| I want one of these with an LTE modem on it so that I can drop it
| in the rack (non-datacenter) and remote-in regardless of the WAN
| condition.
| deivid wrote:
| i used to have one of those "hdmi over ethernet" devices which
| i captured with ffmpeg and used for his purpose. worked well,
| about 100ms latency for the capture/conversion
| paranoidrobot wrote:
| It's a Raspberry Pi, so there's no reason you can't plug a USB
| LTE Modem into it.
|
| You'd have to figure out how to get inbound connections -
| perhaps something like tailscale would do the trick.
| burnte wrote:
| I've been trying to design one that takes VGA in as that's what
| servers come with. An LTE modem is trivial to add.
| sneak wrote:
| COTS VGA to HDMI adaptors are readily available.
| burnte wrote:
| For my design I don't want that, because then we're just
| making it even more complex. I'd have to have an HDMI
| ancoder, then a VGA to HDMI encoder that plugs into that.
| There's a VGA encoder I've been working on, I don't recall
| the chip ID but I found it in the Lantronix Spiders I have.
| I've been slowly trying to build a HAT with that that pipes
| into the Pi for everything else. Then there is no daisy
| chaining adapters.
| jhgb wrote:
| So is a VGA digitizer that plugs into a USB port, presumably?
| burnte wrote:
| For my design I don't want that, because then we're just
| making it even more complex. There's a VGA encoder I've
| been working on, I don't recall the chip ID but I found it
| in the Lantronix Spiders I have. I've been slowly trying to
| build a HAT with that that pipes into the Pi for everything
| else.
| phaer wrote:
| At least the TinyPilot firmware is Open Source
| https://github.com/tiny-pilot/tinypilot - i don't know Pi-KVM.
| And it's a normal RaspberryPi with a debian-based os. So you
| should be able to just attach an LTE modem via USB and
| configure it via SSH, right?
| krasin wrote:
| pikvm is open source as well: https://github.com/pikvm/pikvm
|
| In fact, TinyPilot is based on ustreamer, that is developed
| by Maxim Devaem, the pikvm creator:
| https://github.com/pikvm/ustreamer
| EricE wrote:
| Yeah, it should be pretty easy to add an LTE modem.
| Configuring the networking failover might take some hands on
| work; it would be a huge boon if either or both projects
| eventually took care of that for you too. I've had enough
| experiences where out of band management would be well worth
| the cost of the cell service that this is something I could
| see having wide appeal.
| osamagirl69 wrote:
| I am pretty sure all you would need to do is plug in a usb LTE
| modem to make that happen.
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