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msisk6 9 hours ago [-]
These aluminum extrusions are called T-Slot, or as McMaster-Carr calls it, "T-Slotted Framing". Very common in industry; we have it everywhere on the Boeing factory floors. Not cheap, but very durable and reusable. Highly recommended.
Check it out starting on page 2240 of your McMaster-Carr 132 catalog. They have all kinds of things you can mount up like monitor arms. It's an erector set toy for engineers. ;)
I have a couple of these, they are made of a light gauge sheet metal; the inner dimension is ~9.75", wider than the 10" standard hole spacing; and I don't think they would be very structurally sound if you were to remove the back panel. Doesn't seem very well suited to me.
Thanks for sharing. I’m running a lack rack for 15 years, would have been fitting
addaon 3 days ago [-]
Why use the original power bricks, with the space claim and awful routing, instead of just going to a single dc/dc... either directly if no individual power control is needed, or to a relay block or switch block if automated / manual individual control is needed?
inickt 8 hours ago [-]
I remember seeing this great video where they built their own power supply for their mini rack. Quite a project but ended up being a pretty cool solution to the problem.
I haven’t found a solution for a single DC power supply I can connect to the systems. Maybe I have to solder something together myself.
hydrogen7800 9 hours ago [-]
Man, I spent a lot of time looking for something like this when i bought my NAS and got annoyed with all the power bricks. Guitar players use them[0] to power their several guitar pedals, but the polarity, voltage and plug form factors are all the same, as far as I know. The various devices i have use slightly different plugs, polarities and i think not all are 12VDC.
I'm very surprised that nothing like this exists in the tech/IT space. There can't be that many form factors, voltages, etc. to deal with.
Some are 12v. Some will take 18v. I have an oddball that takes 9V AC. Some are 9V DC but flip the positive and negative. It can be a mess too.
The product you link to has outlets for 9V, 12V and 18V.
If you stuck to one PC manufacturer, I’d imagine you could have your wish. Dell laptops were the same 19V and same DC pin for years and years.
I thought USB-C PD would save us but it has a few pitfalls, apparently.
zeckalpha 6 hours ago [-]
Pedal polarity is inverse of typical barrel plug polarity though.
addaon 3 days ago [-]
Meanwell is the standard answer for this sort of thing; something in the SD-500 family or sized/optioned as you need. You'll have to do the connectors yourself; you may be able to find junction-post-to-barrel-plug leads of the right size and length off the shelf, but I'd be surprised, and soldering them would take less time than shopping for them.
Also, not sure why you're suggesting a DC-DC supply here? His input is AC.
louwrentius 11 hours ago [-]
Thank you
briHass 9 hours ago [-]
An old PC ATX power supply is great for most things that use 5/12V. You get the 2 most common voltages for network gear, with plenty of capacity and efficiency (with a decent PSU.)
You do have to solder, though I wouldn't be surprised if one can find sata power to barrel adapters on AliExpress.
swed420 9 hours ago [-]
They make breakout boards that mate with the main ATX motherboard connector on the PSU. Bonus that some of them even include fuses.
And at that point, why not just chop up an old ATX case to house everything, assuming there's clearance.
2 hours ago [-]
nl 5 hours ago [-]
I got the TecMojo 10" 6U rack[1] from Amazon for less than $100. It's great, and even came with 2 HTML USB adapter boards (I think for some variety of R-PIs?)
Getting something with actual, standard rack-mounting points is worth it because you can use the huge variety of 3D printed hardware to match it very easily.
I agree with the other commentators that power bricks are a problem though. My setup is fanless and silent which is an extra challenge.
It would be cool to design custom aluminum brackets for the fans. However I found that although ordering 3D prints is very cheap, using (for example) PCBWay for CNCing something out of aluminum is very expensive.
throwaway219450 7 hours ago [-]
Try to avoid milling unless you absolutely need it. Better to go 2D with some tolerance and print small adapters, or use standard T-slot hardware, to connect it. It's often educational to browser McMaster just to get a feel for what standard parts even exist.
For a bracket I would look at a laser or waterjet service. Sendcutsend is one of the more well known web shops and the pricing is OK for the convenience. Also look out for local places that are linked to education. Some libraries even have laser cutters. One shop near us will do simple jobs for machine time + material cost, like you give them a DXF and they'll cut acrylic for a good price. Other option for metalwork is to join a makerspace. The dues are often very reasonable vs trying to get a lathe into your house.
farfatched 6 hours ago [-]
I do some FOSS work with bootloaders and would love a cheap setup where I could leave boards running and have remote access to their UART/SPI/power.
Occasionally I need to be able to get physical access to it too.
I use esp32 for the remote UART/SPI, but don't really have a good setup for keeping a few projects tidy, and with the ability to move it from its remote location (a bookshelf) to my desk for physical access.
Does anyone know of any cheap and dense way to store these projects/boards?
BobbyTables2 4 hours ago [-]
Nice writeup!
Always thought extrusions were expensive. At least had found a company custom cutting them but the price was something like 20x what you got.
TacticalCoder 3 days ago [-]
This looks good: I've got three HP NUCs like in TFA + three Pi on my desk (got more than that altogether) and it's indeed a cable mess.
> Aluminium extrusions are bars with a groove on all four sides. These bars have a standard format and you can slide all kinds of equipment in there and lock it in place with set screws. It seems to be used a lot for home made 3D printers, CNC machines and whatnot.
They're also called "T-slot" and 80/20 (from the brand).
Plenty of free 3D models for tiny parts for those that can be printed at home (careful though: most won't hold much weight).
pseudohadamard 2 days ago [-]
Built something fairly similar about 15 years ago. The cheapest way by far to do it is get everything you need off Aliexpress except the alu sheets which you can typically get as offcuts from local manufacturers, I was lucky enough to pick up some odd shapes that had been used for signage for next to nothing that I could cut to the right size. Since you need to buy bags of 50 or more of the M5 fixings, you an bundle them up and recover some or all of the cost by selling them locally once you've used the few you need.
blablabla123 2 hours ago [-]
Have you taken grounding into consideration?
louwrentius 34 minutes ago [-]
The chassis is not connected to ground, tbh. Not really.
ssl-3 10 hours ago [-]
Which part of this is a "rack"?
someonebaggy 8 hours ago [-]
the whole thing?
ssl-3 7 hours ago [-]
Which part do I mount one of these 10" rack-mount switches[1] to?
I think the issue is that these arent close to rack specification. So its a rack in that its a set of shelves, but its not a Rack as the technology industry would define it.
markhahn 10 hours ago [-]
we call that a shelf.
shuwix 2 hours ago [-]
O call it shelf for stupid HP shitboxes, with no redundancy, high consumption and low performance.
I bet these are old corporate scrap metal with something horrid like i3-9100T.
Nothing a wall mounted Chinese NUC with 12-13th gen i7, 2x32GB DDR4, 2x PCI-e 4.0 NVMe, 2x LAN can't do much better for price of that NOT-rack and fraction of electricity.
Check it out starting on page 2240 of your McMaster-Carr 132 catalog. They have all kinds of things you can mount up like monitor arms. It's an erector set toy for engineers. ;)
https://www.ikea.com/us/en/p/helmer-drawer-unit-on-casters-b...
https://youtube.com/watch?v=8tTG0TBM7ts
https://www.reddit.com/r/homelab/comments/1qh13nu/i_made_a_p...
I'm very surprised that nothing like this exists in the tech/IT space. There can't be that many form factors, voltages, etc. to deal with.
[0] I think something like this: https://www.monoprice.com/product?p_id=600062
Some are 12v. Some will take 18v. I have an oddball that takes 9V AC. Some are 9V DC but flip the positive and negative. It can be a mess too.
The product you link to has outlets for 9V, 12V and 18V.
If you stuck to one PC manufacturer, I’d imagine you could have your wish. Dell laptops were the same 19V and same DC pin for years and years.
I thought USB-C PD would save us but it has a few pitfalls, apparently.
https://www.ebay.com/itm/235241551377
The SD-500 is available in 12V, 24V, and 48V, none of which adjust to that range:
https://www.meanwell.com/Upload/PDF/SD-500/SD-500-SPEC.PDF
Also, not sure why you're suggesting a DC-DC supply here? His input is AC.
You do have to solder, though I wouldn't be surprised if one can find sata power to barrel adapters on AliExpress.
And at that point, why not just chop up an old ATX case to house everything, assuming there's clearance.
Getting something with actual, standard rack-mounting points is worth it because you can use the huge variety of 3D printed hardware to match it very easily.
I agree with the other commentators that power bricks are a problem though. My setup is fanless and silent which is an extra challenge.
[1] https://tecmojo.com/collections/mini-server-rack
For a bracket I would look at a laser or waterjet service. Sendcutsend is one of the more well known web shops and the pricing is OK for the convenience. Also look out for local places that are linked to education. Some libraries even have laser cutters. One shop near us will do simple jobs for machine time + material cost, like you give them a DXF and they'll cut acrylic for a good price. Other option for metalwork is to join a makerspace. The dues are often very reasonable vs trying to get a lathe into your house.
Occasionally I need to be able to get physical access to it too.
I use esp32 for the remote UART/SPI, but don't really have a good setup for keeping a few projects tidy, and with the ability to move it from its remote location (a bookshelf) to my desk for physical access.
Does anyone know of any cheap and dense way to store these projects/boards?
Always thought extrusions were expensive. At least had found a company custom cutting them but the price was something like 20x what you got.
> Aluminium extrusions are bars with a groove on all four sides. These bars have a standard format and you can slide all kinds of equipment in there and lock it in place with set screws. It seems to be used a lot for home made 3D printers, CNC machines and whatnot.
They're also called "T-slot" and 80/20 (from the brand).
https://en.wikipedia.org/wiki/T-slot_structural_framing
Plenty of free 3D models for tiny parts for those that can be printed at home (careful though: most won't hold much weight).
[1]: https://mini-rack.jeffgeerling.com/#network-gear
I bet these are old corporate scrap metal with something horrid like i3-9100T. Nothing a wall mounted Chinese NUC with 12-13th gen i7, 2x32GB DDR4, 2x PCI-e 4.0 NVMe, 2x LAN can't do much better for price of that NOT-rack and fraction of electricity.