Nice racks

I think it’s safe to say that I’ve now reached the point where I have too many dev boards to just have them scattered about my desk willy-nilly. Most of them don’t even have cases, so aren’t particularly well protected against flying pieces of food or drink (or other dev boards).

I think the ideal solution to this problem would basically be a mini server rack. Basically just a small, free-standing shelving unit, with a floor footprint of about a foot square (although the boards themselves are quite small, you do need plenty of room to fit all the necessary cables around them). The shelves themselves just need to be a thin sheet of wood, and need to be easily removable (i.e. just slide in and out of place). That way I can easily drill support holes for the boards in order to mount each one to its shelf. Spacing between the shelves probably doesn’t need to be any more than 4 or 5 inches – enough to fit a hand in in order to poke a reset button or mess with an SD card. The bottom of the “rack” could be used to house a network hub and the mountain of PSUs. Ideally it should be possible to close all sides (i.e. fixed walls with a door at the front) in order to prevent accidental food & drink related incidents.

However after a moderate amount of googling I can’t find anything that tickles my fancy. Does anyone here know of anything that would fit the bill?

https://wiki.eth0.nl/index.php/Lackrack ?

http://www.amazon.co.uk/Black-Letter-Filing-Trays-Risers/dp/B008MAY46G

Hmm, that could work. Although it would fall apart if I had to pick it up and move it, which isn’t ideal.

Although it would fall apart if I had to pick it up and move it

If you don’t want it to come apart I dare say a squeeze or two of “No more Nails” or similar would rigidize it a little.

Yeah, I’d imagine it would be possible to glue it together somehow. And then I’d probably find that I do need to take it apart for some reason!

Does anyone here know of anything that would fit the bill?

I typed “nice racks” into the internet and got distracted for a while.

You could start out with some peg board then get some M3 brass PCB standoffs and mount the various eval boards you have on that. If your eval boards don’t fit the peg board pitch you can always drill a few extra holes as required.

Optical stages are also regular metric pitch M4 holes drilled into anodised aluminium, however a small mortgage is required for their purchase. They also have motorised ones for true Bond villain appeal.

I typed “nice racks” into the internet and got distracted for a while.

Hmm… Surf boards, guitars, and a medical centre in Texas…

I typed “nice racks” into the internet and got distracted for a while.

LOL.

However, I selected your text in quotes and tried and the third link down was this which appears to have items in various colours (or colors since it appears to be US based)
Headings on the page are straight, slanted, accessories… as well as “wood panels”

Hmm… Surf boards, guitars, and a medical centre in Texas

The benefits of a local bias to the searches: since the phrase has no regular use in France it biases differently. Mostly on any related items you may have searched for, like my search bringing up equipment racks (19 inch) and wine¹ racks in profusion when I searched.
I think Sprow may need to explain away the google bias in his search :)

¹ ’scuse me mr google but I rarely do wine, beer being much more my thing

I’ve been thinking about this a bit more recently. There are really three problems to solve:

• Housing the boards
• Powering the boards
• IO

IO is an area which has a few interesting possibilities. With 11 dev boards and counting, it’d be unreasonable for me to have a dedicated monitor + keyboard + mouse for each, not to mention wasteful since I’ll rarely have more than one or two powered on at once. A HDMI+USB KVM switch feels like a reasonable solution, if it wasn’t for the fact that most have ridiculous price tags (typically £500+ for an 8-port HDMI+USB KVM – almost as expensive as 8 monitors + keyboards + mice). “Tesla smart” seem to manufacture KVMs at more sensible prices (£150 for an 8-port model, including shipping), but it’s still pretty expensive when you look at the individual costs of HDMI switches and USB switches (£17 for a 4-port HDMI switch, £13 for a 4-port USB switch, so £30 total for a 4-port switching solution – but put both of them together in one box and it costs twice that?).

For network IO, it’s easy enough to connect them all up to an Ethernet switch, so no special solutions needed there. Serial may need a switch box, although for that I think I can stomach just swapping a cable around manually (as long as the serial ports of the machines are readily available).

Power is a bit annoying. You can get reasonably-priced multi-port USB power supplies, but it looks like it’s pretty rare to have any with individual power switches for each port. So it would either require switches on the individual power cables, or lots of plugging in & out to power devices off and on. And about half the boards use barrel connectors for the power input, so will require adapter cables.

Housing is the final piece of the puzzle. I’m toying with the idea of repurposing a PC tower case. With a bit of drilling it should be able to mount the boards to the plate which the motherboard would normally be mounted to (probably with the Pis stacked vertically, to save on their footprint). It should also be possible to fit the network, HDMI and USB switches into the case – although I’d have to perform some surgery on either the case or the HDMI/USB switches to make sure that the switching controls (and status LEDs) are actually accessible. The ideal solution would be to adapt them to fit into a 5.25" drive bay, which sounds do-able, at least for 4-port switches. Likewise, the power switches – a PSU (or at least a switch board) in a 5.25" drive bay would be the most convenient way of controlling power to the individual boards. External serial, network, HDMI and USB connections could be via standard expansion card brackets at the back of the case.

If everything’s going into a PC case, that would also raise the possibility of using an ATX PSU for the power. It’d be a convenient source of power for any IDE or SATA devices, but I’d have to choose the supply carefully to make sure it’ll still work correctly when only one of the devices is powered on.

I think it would be possible to build a working system, but it would take a while, and the cost could mount up pretty quickly (lots of adapter cables, connectors, etc). And it doesn’t really solve the problem of easy SD card access for if I need to recover a bricked machine.

Power is a bit annoying.

Makes you wish all the boards were PoE enabled, then simply turning the individual PoE switch ports on and off would give control from anywhere else on the network.
Approx 13 Watts on the 802.3af standard and 25W on the 802.3at standard. (Unfortunately the 44V at 350mA probably isn’t healthy for any board we are interested in.)

Mind you if you could do some voltage conversion locally then all mains power can sit elsewhere on the network (except the display power…)

A HDMI+USB KVM switch feels like a reasonable solution, if it wasn’t for the fact that most have ridiculous price tags (typically £500+ for an 8-port HDMI+USB KVM – almost as expensive as 8 monitors + keyboards + mice). “Tesla smart” seem to manufacture KVMs at more sensible prices (£150 for an 8-port model, including shipping), but it’s still pretty expensive when you look at the individual costs of HDMI switches and USB switches (£17 for a 4-port HDMI switch, £13 for a 4-port USB switch, so £30 total for a 4-port switching solution – but put both of them together in one box and it costs twice that?).

TBH, my experience of HDMI+USB KVMs says “don’t bother” for another reason, as well as the price. I have a couple (only four port) and they’re both a pain; both behave much the same way (and are probably exactly the same device under the hood) so I’ll describe for just one:

It’s externally powered, but if the source device provides enough power that isn’t needed. Which sounds good on paper – but not so much in practice if you have a mix of machines that do/don’t need them to be powered.

The ARMX6, for example, will happily use it without the external power source. The Pi (the one I use, anyway – the original model) does need that power source to be used.

If power isn’t supplied (even if other machines are on and connected), the Pi suffers from extra or missed clicks/key-presses. If power is added, however, the ARMX6 will no longer talk across the network.

My desktop PC (running Linux Mint) doesn’t have HDMI out, so it’s connected to the screen using VGA, and for the mouse/keyboard there’s a standard USB switch in the mix – so when I’m using the PC, the KVM isn’t used.

Whenever I’m switching from that to a computer that’s connected through the KVM, I usually have to switch the KVM to a different ‘machine’ then back again (even if nothing else is on) before it actually works. It sometimes takes a couple of switches.

The Windows laptop is particularly nasty with this – and this problem is made worse if it sleeps or hibernates. Often when that happens, the easiest solution is to power up a RISC OS box, get the KVM working with that, then switch back to the awakened laptop. (That, BTW, is my current Windows 7 laptop – my previous one ran Windows 8, and it was much worse – the RISC OS trick worked maybe 75% of the time, but when it didn’t the solution was to shut down, disconnect, reconnect, start up.)

Half the time, after getting the KVM working again with the Windows box, it no longer feeds the audio over HDMI to the monitor.

The purpose of these devices is to share the keyboard/mouse/monitor between multiple machines – but if the reason to use one is the convenience of switching with one device rather than a couple, then IMO they aren’t worth the difference in price over a separate (and simple) USB and HDMI switches.

audio

Ah yes, that’ll be something else to add to the cost.

If I had a 3D printer, I’d be tempted to try printing my own custom case, built out of stackable slices. Basically a tall, thin tower that hugs the edges of the different boards. That way I’d be able to access the IO connectors, SD cards, etc. of each board while still keeping the boards themselves protected from the elements. That would make it a lot easier to just swap cables around when I want to switch machine, avoiding the need for expensive and temperamental HDMI/USB switching solutions.

Or I guess I could go with the Blue Peter approach – build a sturdy skeleton (standoffs + wood/plastic/metal sheets whenever the mounting holes change location?), then use something easy to work with like cardboard or papier-mâché for the outer walls. Probably a lot quicker (and cheaper) to design and build, although care would have to be taken to not damage the outer shell when plugging/unplugging things.

Power is a bit annoying.

I recently plugged my devices into remote controlled mains switches. I have my powered usb hub on the same switch as my armx6 – the bare board version which is my main machine – so it starts up at the same time. It makes devices very easy to switch on/off or reset.

I also tend to use your VNC server and Avalanche these days now that I have it working properly with no keyboard plugged into the remote device. I find it easier than switching machines with a usb switch and changing monitor input – not that I have enough monitor inputs any more. VNC also allows me to have access to my main machine at the same time.

I tried many KVM switches during my IT career. Currently, I am using an old Belkin 8 port PS2/USB/VGA switch (console mouse/keyboard must be PS/2, so not exactly future-proof) together with a 4K capable 6 port HDMI switch.

All other switches I tried over the years were…interesting. One could say: completely broken. The worst one was (is!) a “4 port Value 4K HDMI KVM Switch”. Its USB device descriptor is completely broken (and I need to send the info to Sprow…). It can only select a specific port via its (extremely bad) IR remote, the device itself only has a “cycle” button. Sometimes it manages to completely hang after pressing that “cycle” button. You can only switch to a port if its USB is connected and powered – so you cannot quickly connect only HDMI to see the video output of a device. Hotplugging HDMI usually hangs the switch.

The Tesla that Jeffrey found sounds good. Not available from any reseller in Europe it seems, the seller on eBay only offers the 4 port variant and calls it “Telsa”…not sure if I want to try the AliExpress shopping experience. The Smart-Avi HDN-8P is another contender, but lacks buttons to directly switch to a specific device.

In an ideal world, a KVM switch would provide dual-screen capabilities for every connected device. 4K resolution support. Auto-convert between HDMI, VGA and DisplayPort. PS2 and USB, for both devices and console. USB3 support. Audio and microphone switching included.

TBH, my experience of HDMI+USB KVMs says “don’t bother”

I wonder if yours is the same as mine, this one from CPC. I have used it for many months very happily with an AMX6, a Pi, an XP PC and a W10 PC. The one I have has a Lindy badge at much the same price, but not from Lindy themselves, who sell it at a much elevated one.

The box has a USB hub and audio and comes with combined HDMI/USB cables. For 4 machines the convenience is well worth the price.

My desktop PC … doesn’t have HDMI out, so it’s connected to the screen using VGA

Mine connects through a VGA>HDMI adaptor, with just the occasional glitch on switching machine.

My desktop PC … doesn’t have HDMI out, so it’s connected to the screen using VGA

Same here. Although I think it is many months since I used it that way.

!RDPClient works very well and I now only use the PC remotely from this HDMI RPi 3.

Steve:

I wonder if yours is the same as mine, this one from CPC.

Yes, I think it probably is. It’s certainly that size/shape of box – which is much the same size/shape as the 8 port one Jeffrey linked to. It’s on its side between the desktop systems and my letter tray stack, so I can’t check, but I think it has the same text emblazoned on it – so it probably is the same one.

The other one is a Lindy IIRC – same shape/design/etc.

I have used it for many months very happily with an AMX6, a Pi, an XP PC and a W10 PC.

Glitches aside, it does work – it’s the glitches that I find a nuisance; particularly getting a signal through it again after a laptop snoozes – and, of course, the issue I have with the Pi requiring it to be powered, which seems to screw the ARMX6’s networking.

Given that you have both a Pi and an ARMX6 in your list and didn’t comment on that problem, do I assume it doesn’t affect you? (I wonder… which model of Pi? The one I have in use is the original model B.)

John:

Using the PC remotely with RDPClient would mean having two machines switched on when I’m using one just one. If I’m only using a single machine, I usually only power up that one. (Obviously, there are times when I’m switching between machines a lot so have more than one powered – but most of the time, it’s just one.)

Using the PC remotely with RDPClient would mean having two machines switched on when I’m using one just one. If I’m only using a single machine, I usually only power up that one. (Obviously, there are times when I’m switching between machines a lot so have more than one powered – but most of the time, it’s just one.)

I am not very good wih switching machines off even when I will not be using them for some time. (I do switch monitors off.) The Raspbery Pi computers use so little power (less than 0.5 amps at 5volt, leaving them on is not an issue) and in any case a few are online servers.

I use the PC from more than 1 RISCOS RPi, in different rooms.

My Pi is a server, runs RISC OS 24/7 (unless there’s a thunderstorm or risk of). I did a test using a mains power meter. It’s for the PiB, but I’d expect a Pi2 to not be too different given RISC OS is only using a single core and it actually idles slower (900MHz peak/600MHz idle, vs a flat 700MHz for the Pi1).

https://www.heyrick.co.uk/blog/index.php?diary=20150912

Given that, it’s no big deal to just leave it running. http://heyrick.ddns.net/ (and don’t worry if there’s no weather reports, everything is very damp right now and that messes with the 433MHz signal).

Edit: Just did a quick calculation in my head. I could run 12 Pi and 12 Vonets for the power consumption of my PC. <beeeep!> (and…think of all the USB power bricks and leads – what a mess!)

Given that you have both a Pi and an ARMX6 in your list and didn’t comment on that problem, do I assume it doesn’t affect you? (I wonder… which model of Pi? The one I have in use is the original model B.)

My practices probably differ from yours:

• I have the switch always powered.
• My machines are always on.
• All machines use a 1920×1200 resolution matching the monitor.
• The Pi is is a B+.
• The W10 machine is a HANNspree stick, and low power.
• The XP machine is an ageing Toshiba portable.
• The AMX6 is a ‘huge’ box on the desk by comparison and probably uses the most power.
• The AMX6 and Pi use Vonets WiFI and the other two are native.

I do get some hiccups with ShareFS, but attribute that to its inherent flakiness. I am able to VNC the AMX6 to another W10 portable in a remote room.

• I have the switch always powered.
• My machines are always on.
  

That’s interesting – because we both have an ARMX6, and for me if the switch is powered, that machine doesn’t have networking at all while that doesn’t seem to be an issue for you.

Although it looks like the same box, perhaps there is a difference between the switches I have and the one you’re using after all. If these things weren’t far too expensive for what they are, I’d be inclined to buy another – but with two bad jobs out of two at those sorts of prices? No thanks!

I have purchased a four port cheapo USB switch and somewhere I should have a bog standard three port HDMI switch – at some point I intend to swap out the KVM for these, but I’ll put off doing so as long as possible because messing around behind/under my desk isn’t fun.

I also have a “new” Windows 7 PC (still in its box since I bought it in July(?) 2016) that I will eventually set up, so when I do one I’ll also do the other – but when that will be is anyone’s guess. ;)

Crazy idea of the day: Simplify testing of code across multiple machines by creating a VNC client which is able to simultaneously connect to multiple servers, feeding them the same input data from the one user. During normal operation the user would only see a single screen – the result of blending together the screens of all of the servers, using an algorithm that will highlight any pixels which differ. Then if something needs investigating, the user can switch to single-machine mode to allow them to investigate/fix.

And it doesn’t really solve the problem of easy SD card access for if I need to recover a bricked machine.

Soon after posting that, I did realise that you can buy SD slot extenders which use a ribbon cable to allow you to place the slot “anywhere”. So if/when this plan comes to fruition, that’s probably what I’ll be using.

Or you could just script each session to perform a series of clicks and key presses and save the output images for comparison against reference images.