Aaron's blog

I moved my Digikam database from the local SQLite file to a networked MariaDB server.  This was mostly fine but Digikam (8.8.0 version) was performing terribly after any face tagging operation.

I would get frequent Force Quit or Wait? questions from the OS, and the UI would hang for 5-10 seconds.  This was always matched with a face scan job kicking off and showing up in the jobs queue.  Everything generally worked but was incredibly tedious.  ~20,000 images in my collection, BTW.

A few times I went through the DB's config and optimized some things, which helped a little.  Typical tuning things like increasing memory and threads, and bumping up max_allowed_packet as recommended.  Still the issue persisted.

Eventually I learned that there is a Enable background face recognition scan setting.  It seems obvious in retrospect, but this completely fixed the issue.  I will just need to periodically rescan for faces now to apply what training has been done since the last run.

I recently purchased a used SuperMicro SuperServer E300-9A-4C because I had come upon a bunch of 64GB ECC RDIMM sticks from the e-waste pile and supposedly it could handle four of them.  This makes for a power efficient way to get 256GB of RAM in a homelab node, although it is a bit weak on CPU at 4 cores.  I would have preferred a SYS-5019A-FTN4 with 8 cores but couldn't find used ones for sale.

The used server from eBay of course did not come with a power supply so I had to order one and wait a while.  Finally that arrived so I stuffed in 4x Samsung M393A8G40AB2CWE sticks and booted up the Proxmox installer.  After a very long wait for memory training or something, it would get to the first screen where I could choose graphical or terminal install.  And then after choosing either one I would get the "Loading initial ramdisk" message and then it would freeze at a black screen.

Eventually I found some errors in the IPMI's Server Health Log.

Uncorrectable ECC @ DIMMB2 - Assertion

Sometimes it would be DIMMB1 too.  I swapped out both B1 and B2 and still had the same issues.  Then I ran the memtest86 program via the Proxmox installer's Advanced Options and sure enough it failed after less than a minute, right at the 130GB mark.

I swapped out for 4x 32GB SK Hynix HMA84GR7MFR4N-TF sticks and the memtest ran for a while.  Next I tried the Proxmox installer and that ran as expected too.

So 128GB of RAM in the system is good enough for me that I don't want to sink hours more into figuring out why the larger ones aren't working.  This has to be a very rare configuration for such a small server with low CPU power, so it wouldn't surprise me if there are hardware limitations.  Or I am simply not looking carefully at module speeds, timings, etc.

Our Hatch Rest+ 2nd gen lost all battery functionality.  If lifted off of the wireless charging base for a fraction of a second it would die.  It was replaced under warranty, and customer support even saw the second one on the same account and said it would eventually develop the same issue.  So they replaced that one too!  Great customer service, which is really what is necessary to make the best out of what I'm sure is a bad situation for them.

Most exciting for me about the whole situation was the opportunity to tear apart the old one!

Tearing off the rubber pad on the bottom reveals some screws, and then the wireless charging module comes out.  Also found here are the barrel jack, and the power and sync buttons.

Here is the component side of the wireless charging board:

With the removal of the two middle screws shown in the first picture, the top of the cone comes off.  There are some tight wires.  The battery and speaker ones each have three wires and seemed to pop off easily.  The single wire is for the metal touch ring and I think I stretched that one to a damaging extent.  I didn't plan to put it back together though.

Access through the top is by prying off the speaker grill:

The speaker is held on by a few screws:

And within there is the battery:

The battery is a single 18650 cell:

It has a BMS.  The voltage directly on the battery was effectively 0V.

Now the main board.  This picture is after I had pried the SD Card out.  You can see that I damaged the card holder, but the card itself was fine.  Like many of the cable plugs within, it had a small dab of glue on it.

The SD card is 16GB and has a FAT32 filesystem.  I found about 7GB of mostly files on there.  Curiously, it seems to have all of the files for several Hatch products.  Folders include:

• Rest_Sounds
• RestMini_Sounds
• Restore_Sounds
• Sleep_Sounds

Another folder is named Downloaded and contains two interesting files.  BeRIOTGameMusicTTR_20220607.mp3 is an hour-long rendition of what I think is the Peaceful Flute music.  And RIOT_BrownNoise_CGV3_20240115.wav is a short clip of white noise.

Removed the plastic ring:

Here is the 7 segment display.  It appears to be individual LEDs behind 7 slots.

Here is the flip side of that main board:

Espressif ESP32-WROVER-E processor:

It has been about two years since we purchased an entry level RO water maker kit (Aquatic Life RO Buddie 4-Stage Reverse Osmosis Deionization Water Filter System RO/DI Filtration Units for Aquarium, 50 GPD) to make "distilled" water for some ultrasonic humidifiers in our house.  This type of humidifier is capable of vaporizing the minerals in tap water which then deposit themselves in a thin film on everything in your house.  Using distilled water is hence required/recommended, and using RO water is good enough according to some people and to my experience.

So now two years later and a wild guess of 400 gallons produced, is it time to replace the consumables in my RO setup?  Here are the numbers:

In three minutes it produced 420ml pure water and 1450ml waste water.  Per hour that is 8.4 liters (2.2 gallons) and 29 liters (7.7 gallons).  Roughly 1:3.5 ratio which seems to be about expected.  I did the same calculations when new--of course I did not save them but from memory this was about the same.

Input water measures 279 ppm TDS and 4.3C temp.  Product water measures 0 ppm and waste water measures at 340 ppm.

My verdict: It is performing fine, I will replace the carbon and sediment filters as recommended, at a cost of $7 each.  Mainly this is to eliminate worry of chlorine damaging the membrane.

Some notes on the setup as seen in the picture:

• The feed tees off of the washing machine supply line.  And the dryer tees off of it too so there is a lot going on there compared to the average washing machine!
• The feed runs into a garden hose timer so I can set it to 45 minutes and walk away.  For the first year we had it connected to the faucet and would set a timer when starting it, so then have to go back and stop it.  This way we also have use of the sink.
• The assembly is mounted inside of the laundry sink.  This way if something leaks there are decent odds that it will not be a house-flooding occasion.
• Pure output goes straight into a watering can which we use to fill the humidifiers.  The waste line is tucked into the drain of the sink.

Update: after replacing those two filters, things seem a little worse.  In three minutes the numbers were 410ml and 1550ml.  I have no theories for this.  Certainly there is some measurement error but I think this would be at the upper bounds of error to be found in my methods.  So maybe.

We gave out fruit snacks, which came in a box of 160 packages. Each one contains a stingy 6 gummies.  When I counted this morning, 90 remained. We ate four last night, leaving 66 given to trick-or-treaters.

I ate two this morning while counting.