Custom JBOD "Motherboard"

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TheGuyDanish

Member
Apr 12, 2022
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Inspired by https://www.servethehome.com/sas-expanders-diy-cheap-low-cost-jbod-enclosures-raid/, my shallow-depth rack (500mm) and the fact that I live in an apartment, I was looking for rackmounted, short-depth cases available in Europe and found a pretty meh market. The best option was Sliger's CX3701 which I could even get sliding rails for. The only downside to that was the fact that mini-ITX is quite restrictive with IO. So I wanted to turn it into a proper JBOD, and I wanted to do it in a slightly fancier way than an empty motherboard and/or a power supply jumper.

So I made a board that could control the JBOD for me instead, kinda like a Supermicro PTJBOD-CB3:



The board has an RP2040 microcontroller that controls the power supply on/off state via an SR latch so the micro can be reset without interrupting the flow of power. A W5500 chip enables remote management via TCP/IP. I've created a small web interface to house all the the functions. An EMC2301 fan controller can drive the fans, and the software actively monitors the on-board DS18B20 temperature probe (or one attached to the J9 header and placed wherever in the case) and adjusts the fan duty according to a configurable fan curve.

The PCI-e slot delivers 12v and 3.3v power to run a SAS expander. I've only tested it with an Adaptec AEC-82885T expander which worked perfectly. I've got an HP 6Gbps expander (I forget the name) that I still need to test with.

The design, including production files, is open source and a permissive license and available on GitHub
Similarly, the software is available under an MIT license, also available on GitHub

More pictures, including it in my CX3701 are here on Imgur.

It is finished for now and I've shipped 12 units to an archival project (Riff.CC) which sponsored my production run of 20 boards. Of course, I have ideas for future revisions:

- A version with a T113-S3 SoC, that way I could run a full Linux system with 128MB RAM on the board and not need the SPI-based Ethernet chip, since the T113 has a built-in GigE MAC.

Hope you folks find it interesting, I have a few boards in stock in case anyone would want one for themselves, but may do another run if there's interest for it.
 

faculty3361

New Member
Nov 25, 2024
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Hi I would like to buy one. I created an account just to purchase one if you have any. Please let me know what you need from me. Thanks.
 
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wiggy

New Member
Dec 25, 2021
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Hi,

Looks incredibly cool!

I hope I'm not too late. Would one still be available (for shipping to Germany)?

Cheers,
Wiggy
 

Dave Corder

Well-Known Member
Dec 21, 2015
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I've got two of these sitting on my desk right now while I work on designing a 3D-printed enclosure for it and the SAS expander I'll be using (since one of my disk shelves is a couple of bare 12-bay cages without a proper chassis :) ). Can't wait to get them installed!

I have had a project like this in the back of my mind for a while now, but it was going to take a long time to come to fruition and was never going to be nearly as polished as TheGuyDanish's version. So kudos to him for making this happen and also supporting the community (he's been quick to respond to my emails and help me with a couple technical questions).
 
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squinlan

New Member
Mar 31, 2025
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I too would like to buy one if you have any left. I also made an account for an opportunity to buy one. Please let me know if you need any information from me. Thanks!
 

TheGuyDanish

Member
Apr 12, 2022
22
46
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Man, I'm good at driving new members to STH it sounds like.

I too would like to buy one if you have any left. I also made an account for an opportunity to buy one. Please let me know if you need any information from me. Thanks!
I'll send you a DM in a second. :)
 

Dave Corder

Well-Known Member
Dec 21, 2015
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I'm working on powering one of these through an HP Common Slot (Server) PSU and a GPU Mining Breakout Board, but I'm having a bit of difficulty getting the OpenJBOD board to switch the HP PSU on (using a tiny 12v to 5v converter from +12vsb on the HP side to the +5vsb on the ATX side works like a treat, though).

From what I understand, the PS_ON# pin on the ATX PSU connector gets pulled to ground to switch an ATX PSU on. On the HP PSU side, there's pin 33 called "PSON" that is also supposed to be pulled to ground to switch on the PSU, but simply wiring the ATX PS_ON# to the HP PSON didn't work. I suspect I may also need to something with HP PS_ENABLE (pin 36, IIRC) pin like the breakout board, and/or find a pad on the board that I can pull to ground with PS_ON# instead of directly using the HP Pin 33. Unfortunately I just killed my one spare breakout board that I was using for testing, so that's on hold for a day or two until I can get another one.
 

TheGuyDanish

Member
Apr 12, 2022
22
46
13
I'm working on powering one of these through an HP Common Slot (Server) PSU and a GPU Mining Breakout Board, but I'm having a bit of difficulty getting the OpenJBOD board to switch the HP PSU on (using a tiny 12v to 5v converter from +12vsb on the HP side to the +5vsb on the ATX side works like a treat, though).

From what I understand, the PS_ON# pin on the ATX PSU connector gets pulled to ground to switch an ATX PSU on. On the HP PSU side, there's pin 33 called "PSON" that is also supposed to be pulled to ground to switch on the PSU, but simply wiring the ATX PS_ON# to the HP PSON didn't work. I suspect I may also need to something with HP PS_ENABLE (pin 36, IIRC) pin like the breakout board, and/or find a pad on the board that I can pull to ground with PS_ON# instead of directly using the HP Pin 33. Unfortunately I just killed my one spare breakout board that I was using for testing, so that's on hold for a day or two until I can get another one.
The enclosure looks great. I've not had hands on an HP power supply so I haven't had any opportunity to look at that behaviour, but I would be more than happy to hear your observations.

Your observations on my board are correct. Q1 pulls its input (ATX PS_ON#) to ground when power is applied to the base, which is controlled by the U5/U7 SR latch.
 

Dave Corder

Well-Known Member
Dec 21, 2015
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The enclosure looks great. I've not had hands on an HP power supply so I haven't had any opportunity to look at that behaviour, but I would be more than happy to hear your observations.
I'll definitely post some build notes if/when I get this working.

Your observations on my board are correct. Q1 pulls its input (ATX PS_ON#) to ground when power is applied to the base, which is controlled by the U5/U7 SR latch.
I was just going off the ATX spec, to be honest, but thank you for confirming your implementation details! That's helpful to know.
 

Dave Corder

Well-Known Member
Dec 21, 2015
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I'll definitely post some build notes if/when I get this working.



I was just going off the ATX spec, to be honest, but thank you for confirming your implementation details! That's helpful to know.
Got it working...looks like U2 is responsible for controlling the signals to the PSU, and I found that pulling one of the pins on it to ground (i.e., connecting the ATX PS_ON# signal to it) will switch the PSU on for as long as the pin is pulled down. It's the same pin that's connected to the switch (or button, depending on which version of the breakout one has). Pics and more details to come tomorrow...