Category: project

APC Back-UPS capacity upgrade (#P11F1)

Was that foreseeable? Not sure, but the design called for it…

Now that my modified APC UPS is running smoothly again (#P11), I still had two pairs of these nice XT60 connectors laying around. And as old, to-be-recycled lead acid batteries from UPSes pile up at work, I took one or two of them with me for testing at my electronic load. Like previous batteries, quite a lot of them are really toast, but some of them are in decent condition. Not as in “like new, ready for another year of service in a commercial fire alarm system”, but still holding a significant fraction of their original capacity and delivering a suitable amount of current. […]


APC Back-UPS external battery mod (#P11)

Good thing I’m a doofus. While tidying up cables after some keystone module action, I also moved the bulky power supply of my monitor. And then I noticed that the only thing that absolutely has to be on the battery backup outlets of my UPS unit was in fact…assigned to the surge-protected ones that fail when mains power is gone. D’oh. After some cable identification in that tight space, I moved the UPS around a bit and I discovered a drop of liquid. A very dubious drop at a place where liquid would have to seep through 4 centimeters of a wooden table, or somehow permeate 1.5mm of solid steel against gravity’s pull. […]


Revox Evolution front panel repair (#P10F1)

Soo…the Revox thing from #P10 wasn’t done at the time, and when the missing cable arrived from China (“DB9 Male to Female Gold-plated Extension Cable Pure Copper Line RS232 9 Pin Serial Connector Wire COM Core with Double Shield” for a whopping 4.53€), it didn’t really work as expected.

I wondered: Did they do fancy things with the shielding, in order to squeeze out one more connection from this otherwise 9 pin cable? The cable might have different characteristics compared to the metal-to-metal contact of the serial connectors directly sitting on top of each other. […]


Revox Evolution 19″ panel mount (#P10)

Christmas, the fabulous time of the year where you got plenty of free time, but you aren’t supposed to make hell of a noise :suspect:

Happy 2019, y’all!

Having ordered a second 19″ keystone plate recently, I decided to finally make the user panel of my Revox Evolution stereo system into a front-mount panel that fits the outside of the rack. Without, it got even more hidden inside because of the top-mounting system that is used. Here’s an original marketing wankery image from Revox:

So if that unit is sitting inside of a 19″ rack, imagine the user experience (wank, wank) of operating the display if the top part is blocked by other stuff. […]


Fujitsu P20-2 CCFL to LED conversion (#P9)

Okay, so here’s something that I wanted to do for a long time, but it makes no sense in terms of time and money. But hey, I finally did it and it was fun!

I’ve shown my old Fujitsu P20-2 monitor previously as a comparison to the current 3440×1440 setup. It’s an old prosumer-grade 1600×1200 display, 20″, 60 Hz S-PVA panel with VGA and DVI inputs. Really good stuff. I got two of them after they failed by the dozen at university, where the tech guys even did a capacitor swap (these were in the upper three-digit Euro range when new, their replacements are totally overpriced 2560×1440 displays for 700€ a pop). […]


ESP8266-DHT22-SR501 kitchen lights thingamabob PCB (#P7F1)

Alright, software aside, back to hardware…

The ESP module shown in #P7 slowly gathers dust in my kitchen, which is tolerable for a few weeks, but that’s not the solution I want long-term. Also, it’s on a separate power brick, meaning there are two microcontrollers running in my kitchen for doing fancy light switches and some air quality logging for twice the standby current. Nope, has to go, needs to be consolidated into one unit.

So a while back I designed this PCB and ordered it (once again) at OSH Park, together with some teeny-tiny DIP adapters that cost next to nothing. […]


FlowerPower LED GrowLight POWERLIGHT 400W Repair (#P8)

Yeah, sorry for not delaying this until I could declare project #P420, but sometimes I’m a little impatient to get content online. After all, I’m not as enthusiastic about this silly number as some folks apparently are. Which also means I’m getting paid in hard cash and not in kind…

So for today’s repair project I have a quad-100W growlight unit on my desk that was in mortal agony when it arrived. The thing does not have a power-on indicator (usually you do know when it’s on…), all it did was some dim, erratic flickering of the LEDs. […]


DHT22 WiFi (ESP8266) temperature/humidity loggers (#P7)

Guess who was busy and also did not prepare a post in advance? Yeah, lazy me :mrgreen:

Well, let’s pick up some project that I’m deploying slowly around my flat. I intend to run five of these devices, one with some light meter and maybe other outdoor sensors, the others will be indoors. I’ve been running the early prototype for quite some while now, doubling as a Blynk gateway to some LED strips in the liquor cabinet (yeah, I called it Boozy McBoozeface for a reason). Accessing lights at home from far away isn’t that important to me, so once I have time to install some more touch buttons, that one will be no longer running Blynk, probably eliminating some timing/connectivity issues. […]


Supermicro Case and Rails (#P6)

Supermicro – the case manufacturer of choice for people with money. :lol:

This is not so much about Wan Hung Lo price ranged products, but rather about construction techniques. And it’s not even about “we made it this way because it’s the cheapest” – it’s about design that yields the most profit for the manufacturer. Vendor lock-in and all that stuff.

Well, I’m more of a Chenbro guy for reasons that I’ll explain in a bit, but I recently did a classic Dave Jones dumpster dive (with permission), from which I got not one, but four Supermicro cases. […]


A beefy electronic load (#P4F2)

Hello again!

I’ve been asked: What do you do with this electronic load thing? Well, I‘ve been using it as a battery torture device, what else could you do with a variable resistance device…

For a crude first step in actually testing my unit and also classifying a newly harvested set of deeply discharged 18650 cells, I slapped together some minimalistic Arduino program and hooked the thing up in parallel to the battery under test. The electronic load was set to 2 Amps with another battery, which was monitored by the Uni-T 203A current clamp. […]