Mar 242018
 

So, I’ve now moved the ADSL and router onto the battery supply. This has added an extra amp of load, but really, the solar panel handles this easy.

I dug up one of my spare switchmode PSU modules and then got to thinking about how I’d mount the thing. In the end, double sided tape… to keep the terminals of the adjustment pot from shorting, to a piece of old copper clad PCB from the project graveyard, with some wires soldered on.

The donor PCB already had regions cut out for terminals around the edge, so I could use those for drilling mounting holes. I just made additional terminal pads for soldering the input and output supply rails. Initially I tried putting a 1mF capacitor across the output, but evidently the one I grabbed was crook as it presented a 10Ω load. I don’t think the cause was due to it charging. The PSU has a 220µF there already, so let’s see how it fares.

Fairly simple, +12V comes in via the orange wire into IN+, the “LM2596” steps that down to 5V, comes out the red wire. Screw terminals allow me to swap input and output.

Before hooking it up to the ADSL modem, I made sure to dial it in to 5V.

Meh… who’s going to care about 3mV. 🙂

As it happens, the original PSU puts out 5.3V. I think I’m closer. I can always dial it up if needed.

I put the lid on the case and made up the rest of my wiring harness. One 5A blade fuse, a bit of work around the back of the rack, and it was installed.

In the meantime, I have my old server busy pushing its last daily back-up across to a newly provisioned virtual machine on the cluster.

One problem this presents is that this one VM occupies about 70% of my usable storage cluster capacity. The cases can take one 2.5″ HDD, which unless you’re willing to risk it with Seagate (I’ve had too many of them fail), top-out at 2TB.

There are SSDs too, but I’m not made of money, and I’ve already spent the cost of a small car on this cluster as it is. My thinking is I might look at modifying the cases with a new lid to accept a 3.5″ HDD. If I make the case a wee bit taller, a 3.5″ HDD would fit in the lid, and I could add fans around it to cool it.

The other option is to make external eSATA 3.5″ DIN-rail mounted cases. I did look online, but didn’t see any for sale. That said, space is getting squeezy on that DIN rail, and I do have to be mindful of cooling.

Mar 232018
 

So last week, I came home to no power, which of course meant no Internet because the ADSL service is still on mains power.

This is something that’s been on my TO-DO list for a while now, and I’ve been considering how to go about it.

One way was to run 12V from the server rack to the study where the ADSL is. I’d power the study switch (a Cisco SG-208), the ADSL modem/router (a TP-Link TD-8817) and the border router (an Advantech UNO-1150G).

The border router, being a proper industrial PC is happy with any voltage between 9 and 32V, but will want up to 24W, so there’s 2A. The ADSL modem needs 5V 1A… easy enough, and the switch needs 12V, not sure what power rating. I’m not sure if it’ll take 15V, I’d be more comfortable putting it on an LDO like I did for the Linksys switch and the cluster nodes. (Thanks to @K.C. Lee for the suggestion on those LDOs.)

With all that, we’re looking at 3-4A of current at 12V, over a distance of about 5 metres. The 6 AWG cable I used to hook panels to solar controller is obviously massive overkill here, but CAT5e is not going to cut it… it needs to be something around the realm of 12 AWG… 20 at the smallest.

I have some ~14AWG speaker cable that could do it, but that sounds nasty.

The other approach is to move the ADSL. After finding a CAT3 6P4C keystone insert, I dug out some CAT5e (from a box that literally fell off the back of a truck), slapped my headlamp onto my hard hat, plonked that on my head and got to work.

It took me about an hour to install the new cable. I started by leaving the network-end unterminated, but with enough loose cable to make the distance… worked my way back to the socket location, cut my cable to length, fitted the keystone insert, then went back to the ADSL splitter and terminated the new run.

There was a momentary blip on the ADSL (or maybe that was co-incidence), then all was good.

After confirming I still had ADSL on the old socket, I shut down the router and ADSL modem, and re-located those to sit on top of the rack. Rather than cut new cables, I just grabbed a power board and plugged that in behind the rack, and plugged the router and modem into it. I rummaged around and found a suitably long telephone cable (with 6P6C terminations), and plugged that in. Lo and behold, after a minute or two, I had Internet.

The ugly bit though is that the keystone insert didn’t fit the panel I had, so for now, it’s just dangling in the air. No, not happy about that, but for now, it’ll do. At worst, it only has to last another 3 years before we’ll be ripping it out for the NBN.

The other 3 pairs on that CAT5e are spare.  If I want a 56kbps PSTN modem port, I can wire up one of those to the voice side of the ADSL splitter and terminate it here.

I think tomorrow, I’ll make up a lead that can power the border router directly from the battery.  I have two of these “LM2596HV” DC-DC converter modules.  I’m thinking put an assortment of capacitors (a few beefy electrolytics and some ceramics) to smooth out the DC output, and I can rummage around for a plug that fits the ADSL modem/router and adjust the supply for 5V.  I’ll daisy-chain this off the supply for the border router.

We’re slated for Hybrid Fibre Coax for NBN, when that finally arrives.  I’ll admit I am nowhere near as keen as I was on optic fibre.  Largely because the coax isn’t anywhere near as future-proofed, plus in the event of a lightning strike hitting the ground, optic fibre does not conduct said lightning strike into your equipment; anything metallic, will.

By moving the ADSL to here though, switching to the NBN in the next 12-24 months should be dead easy.  We just need to run it from the junction box outside, nailing it to the joists under the floor boards in our garage through to where the rack is.  No ceiling/wall cavities or confined spaces to worry about.  If the NBN modem needs a different voltage or connector, we just give that DC-DC converter a tweak and replace the output cable to suit.

We of course wait before switching the DC supply until after we’ve proven it working from mains power in the presence of the installer.  Keep the original PSU handy and intact for “debugging” purposes. 😉

There is an existing Foxtel cable, from the days when Foxtel was an analogue service, and I remember the ol’e tug-o-war the installer had with that cable.  It is installed in the lounge room, which is an utterly useless location for the socket, and given the abuse the cable suffered (a few channels were a bit marginal after install), I have no faith in it for an Internet connection.  Thus, a new cable would be best.  I’ll worry about that when the time comes.

On the power supply front… I have my replacement.  The big hold-up with installing it though is I’ll need to get a suicide lead wired up to the mains end, then I need to figure out some way to protect that from accidental contact.  There’s a little clear plastic cover that slips over the contacts, but it is minimal at best.

I’m thinking a 3D printed or molded two-part cover, one part which is glued to the terminal block and provides the anchor point for the second part which can house a grommet and screw into the first block.  That will make the mains end pretty much as idiot-resistant as it’s possible to be.  We’ll give that some thought over the weekend.

The other end, is 15V at most, I’m not nearly so worried about that, as it won’t kill you unless you do something incredibly stupid.

Mar 172018
 

Last night, I got home, having made a detour on my way into work past Jaycar Wooloongabba to replace the faulty PSU.
It was a pretty open-and-shut case, we took it out of the box, plugged it in, and sure enough, no fan.  After the saleswoman asked the advice of a co-worker, it was confirmed that the fan should be running.
It took some digging, but they found a replacement, and so it was boxed up (in the box I supplied, they didn’t have one), and I walked out the door with PSU No. 3.
I had to go straight to work, so took the PSU with me, and that evening, I loaded it into the top box to transport home on the bicycle.
I get home, and it’s first thing on my mind.  I unlock the top box, get it out, and still decked out in my cycling gear, helmet and all (needed the headlight to see down the back of the rack anyway), I get to work.
I put the ring lugs on, plug it into the wall socket and flick the switch.
Nothing.
Toggle the switch on the front, still nothing.
Tried the other socket on the outlet, unplugging the load, still nothing.  Did the 10km trip from Milton to The Gap kill it?
Frustrated, I figure I’ll switch a light on.  Funny… no lights.
I wander into the study… sure enough, the router, modem and switch are dead as doornails.  Wander out to the MDB outside, saw the main breaker was still on, and tried hitting the test button.  Nothing.
I wander back inside, switching the bike helmet for my old hard hat, since it looks as if I’ll need the headlight a bit longer, then take a sticky beak down the road to see if anyone else is facing the same issue.
Sure enough, I look down the street, everyone’s out.
So there goes my second attempt at bootstrapping Gentoo, and my old server’s uptime.
The power did return about an hour or so later.  The PSU was fine, you don’t think of the mains being out as the cause of your problems.
I’ll re-start my build, but I’m not going to lose another build to failing power.  Nope, had enough of that for a joke.
I could have rigged up a UPS to the TS-7670, but I already have one, and it’s in the very rack where it’ll get installed anyway.  Thus, no time like the present to install it.
I’ll have to configure the switch to present the right VLANs to the TS-7670, but once I do that, it’ll be able to take over the role of routing between the management VLAN and the main network.
I didn’t want to do this in a VM because that means exposing the hosts and the VMs to the management VLAN, meaning anyone who managed to compromise a host would have direct access to the BMCs on the other nodes.
This is not a network with high bandwidth demands, and so the TS-7670 with its 100Mbps Ethernet (built into the SoC; not via USB) is an ideal machine for this task.
Having done this, all that’s left to do is to create a 2GB dual-core VM which will receive the contents of the old server, then that server can be shut down, after 8 years of good service.  I’ll keep it around for storing the on-site backups, but now I can keep it asleep and just wake it up with Wake-on-LAN when I want to make a back-up.
This should make a dint in our electricity bill!
Other changes…

  • Looks like we’ll be upgrading the solar with the addition of another 120W panel.
  • I will be hooking up my other network switches, the ADSL router and ADSL modem up to the battery bank on the cluster, just got to get some suitable cable for doing so.
  • I have no faith in this third PSU, so already, I have a MeanWell HEP-600C coming.  We’ll wire up a suicide lead to it, and that can replace the Powertech MP-3089 + Redarc BCDC1225, as the MeanWell has a remote on/off feature I can use to control it.