Won’t Get Fooled Again . . .

No critique or judgement implied in the title of this post, just the lyrics of The Who’s song “…meet the new boss…same as the old boss…” percolated to the surface as I came across this press release last recently:

MTE Relaunches Prestigious TEALĀ® Brand for Precision Power (March 30, 2022)

Teal Electronics Corporation was my first and best client for many years. I worked closely with them developing and managing the PDU (Power Distribution Unit) for medical imaging systems with my then-employer Philips Medical Systems. I’ve consulted with them for ages – working on training, applications notes, customer support (remote and in the field).

I’m particularly fond of an Excel based viewer for their TEALwatch product – which you can see a bit of the GUI from here – Dedicated Line, Back to the Service Entrance

Times change, principals and technical contacts move on, we dropped the retainer in 2011, and my last invoice to them was 2015. They were purchased by MTE Corp in 2016, and despite a few fleeting contacts, my relationship with the company effectively ended. My guess is that the TEAL business unit itself got a bit lost in the shuffle.

They do seem to have tweaked the logo a bit. So that’s something . . .

I’m only slightly amused / disappointed that the sum total of the MTE / TEAL application library consists of 3 applications notes, the last survivors of a series I wrote for TEAL back in 1995….


Upgrading Tech: PC Workstations

It’s been a long time since I’ve had to purchase a PC / workstation for my office (I bought a pretty fast / powerful workstation many years ago and it’s still doing the job). But I’ve had to pick up some new tech for the studio over the past few years.

When we started to live-stream yoga classes, I needed to invest in some laptops. Realizing there was no need for a lot of permanent memory (these are are effectively single application Zoom streaming devices), I opted for devices with SSD memory: an I3 for the portable zoom cart, an I5 for the Studio A permanent streaming device (Zoom has some guidelines on device minimums). So far, so good on both accounts.

The laptops were inexpensive enough that I decided to invest in one for my own yoga room. Again, no significant need for on-board storage, so a device with an SSD promises to be faster (booting / memory access) and with the biggest potential failure point (the hard drive) eliminated. Amazing that memory tech has gotten so powerful and so inexpensive.

As we crawl our way out of the pandemic, the studio front desk POS workstations have become a bottleneck – two ancient tower PCs that have become slow, wonky, and more of a challenge for the new cast of staff and work-study, less patient or skilled at working with crappy tech.

Old (right) vs New (left)
The tower was actually the smaller and faster of the two front desk workstations.

Inspired by a mini-PC workstation in the back office (itself a few years old), I went to see what was out there – and what a pleasant surprise! I picked up two of these little dudes:

Mini PC with Windows 11 Pro (8GB DDR4/128GB M.2 SSD) Equip with Intel Celeron J4125 Up to 2.7GHz, Portable Desktop Small Computer, with Dual HDMI, Ethernet, Dual Wi-Fi, Bluetooth and 4K Support

Amazing how tiny these little guys are. The workstations have one purpose – run a web browser to access Mind Body, the web based client management service – no need for a lot of on-board memory or a hard drive. I had to hunt around a bit to find a device with SVGA output (the default is HDMI these days) but I wanted these to be plug compatible with the existing hardware without adapters. Max’d out the USB ports with a mouse, keyboard, bar code reader, and credit card swiper.

I went the extra mile and mounted the new devices on the side wall under the desk, keeping cables secured and nothing underfoot. The desk itself is custom-built, with screens mounted underneath a smoked glass cut-out.


Audio Madness – Livestreaming Yoga

File this one under “never waste perfectly good pandemic” (this stuff is fun) and also under “just in case I get hit by a bus (or a virus)” – leaving breadcrumbs for some future entity picking up the pieces if I wander away (from the yoga studio or off this mortal coil).

Here’s how we make the yoga happen. We started with a simple mixer and amplifier (a standard stereo with A and B speakers) that has been in the studio since Jansen Court (circa 2002), being fed by:
* CD Player (just one teacher uses this regularly)
* Wireless headset (aka “Barbara’s Mic”)
* Phone / MP3 via 1/8″ stereo
* Bluetooth receiver (a fairly recent addition by yours truly)

Once COVID hit and we started moving to livestream classes, I started getting fancy – with a four camera video system, centered on the Blackmagic ATEM Mini Pro and AIDA HD-100A cameras. But the sound….there’s the rub.

The basics – a choir mic (hanging from the ceiling) and a boundary mic (on the floor) near the instructor mat – which does a pretty solid job of picking up the instructor. The Zoom noise filters (and post-processing noise removal for recorded classes) provide reasonable quality. Both room mics require phantom power, so a mixer (that I had on the shelf) was needed, and I initially ported this to the switcher aux inputs (Mic1 / Mic2) via the mixer main output (left / right)

Then it started to get complicated. Teachers use bluetooth or CDs for class music. Teachers want to walk around the room. There are a couple of different headsets in use. So here’s where it has ended up, after many months of evolution, experimentation, and experience.

Room Mics (floor / ceiling) are now panned left (levels set at the mixer, in the room), feeding mono into the switcher Mic1 input.

Headset mics (two types) are now panned right, mono into the switcher Mic2 input.

Headset mics (two types) are also sent via the mixer FX bus to the room mixer (to provide teacher amplification if desired.

CD and Bluetooth outputs are split, feeding the room mixer (dual 1/4″ mono) and two of the AIDA camera inputs (1/8″ stereo), where they run to the switcher via the camera HDMI. Latency is not a huge issue with the audio tracks (was a bit of an issue with voice, we found)

I think I’m (finally) done with all this – there’s plenty of flexibility to set levels, turn things on and off. Been a long time coming…

The Shoemaker’s Children…

….go barefoot. An old proverb that speaks to those with particular skills and aptitude often taking care of their own stuff last. And usually the case with me!

I had a couple of basement outlets / lights go intermittent, I tracked it down to a particular outlet, and so far as a bad neutral (because the voltage tester was chirping on a “dead” outlet.

This noontime, I pulled a shelf away from the wall, pulled the outlet, and heard the familiar (and unsettling) crackle-crackle of arcing as a nearby light on the circuit blinked.

The sparky-monkey who wired the basement (no doubt the former owner) used those stupid / dangerous outlet holes to make connections (called “back-stabbing”) One neutral connection was high resistance, getting warm, and thankfully broke connection before anything caught fire.

I cut out the outlet, replaced with properly screwed down and wrapped around the terminal connections, and all better.

Best of all, since the circuit in question also powered my desktop computer, I got to listen to my UPS chirp while I made the swap (NASCAR-like) and returned the circuit to service with 12 minutes to spare (my UPS is oversized for the load, so lots of battery time).

Blackmagic ATEM Mini Pro (upgrade)

We did not really need this, but the techie in me could not resist an upgrade / reason to mess around with better tech.

The Blackmagic ATEM Mini video switcher ($300) is a pretty sweet device – 4x HDMI inputs, 2x Aux audio in, lots of bells and whistles. However, the only real confidence monitor is a single preview output. Having worked on the periphery of AV production, I had some serious video wall envy.

Top – an inexpensive HD television.
Left – an iPad used as a zoom confidence monitor
Middle – Laptop for zoom
Right – ATEM Mini Pro switcher

Enter the Blackmagic ATEM Mini Pro – about $600 but you get this amazing video output that provides:
* Program / Preview / 4x Cameras (with labels)
* Graphics / Key
* Streaming & Recording
* Audio Indicators

The inset (picture-in-picture) was part of the base model, but having the full video wall makes it easier to use.

The audio indicators are super useful (we were flying blind trying to troubleshoot audio issues) – with 4 camera inputs, 2 mic / aux inputs, and output levels.

The recording (via USB) is a bit of a let-down, since it only works if you are not using the USB output (unfortunately, how we port to zoom)

However, the ability to livestream makes up for that – we use a web based service – Restream.io – to capture classes automatically. The operator simply needs to press the On Air button and the class streams to the restream site – they hold onto the content for 15 days then dump it. Plenty of time to download it and process classes for use on youtube, vimeo, etc.

Sneaky Voltage Swell Events

Long time, no post! A pandemic will do that to you . . . suffice it to say I am healthy, relatively happy, and staying busy with both my engineering work (mostly stable through the troubles) and my yoga studio work (very different these days but busier than ever with online classes and the need to provide appropriate technology).

Today’s engineering bon-bon involves a trio of voltage swell events. Seemingly caused by a short circuit (another facility load fault, perhaps utility lighting arrestors) that causes a 1/4 cycle drop-out on one phase and resultant voltage swell following. The swell has a serious overvoltage, likely to cause problems for many types of equipment / power supplies.

This event was captured as a minor RMS voltage swell (5.1% above nominal) – but the peak voltage is very high (540 V vs 395 V normal). Note the ~30 Amp peak current swell.
This event was barely detectable as an RMS voltage swell (4.8% above nominal) – once I recognized the nature of these events, I went looking for more and came up with just this one. Almost no resultant current swell.
This is the big smoking gun event. Even though it did not register as a sag / swell event at all (the voltage drop-out being balanced by the following swell, just 3.25% over nominal) it was captured as a current swell (the highest current event over 6 weeks of data capture) – 650 Amps waveform peak. Something within the client load saw this event as a problem and drew a slug of current.

I’m just the hired gun reviewing the data, pulling out events and issues, writing a report. So I won’t be following this to a resolution or further troubleshooting on site. But this is a good example why automated report writing is not always sufficient – the Fluke 1750 analysis tools would see these events as minor voltage swells (if that). It takes a human being with some experience (I’ve reviewed over 5000 power quality data sets since 2003) to see something unusual, scratch one’s head, and dig in a bit deeper.

Pandemic Crisis: Danger / Opportunity

Things have been very interesting in the yoga world since the COVID-19 pandemic forced the studio to close in March 2020. I taught my last in person class on March 11th; the studio last class was noon on March 13th.

After a weekend of stunned silence, we were back the following Monday. We started with free classes, live-streamed via Facebook Live and archived there and on YouTube. We started simple – an iPad on a tripod, and slowly added lights, sound (headsets and ambient microphones) as we realized this was not going away quickly. Unable at that time to monetize classes, we set up a couple of membership levels for those wishing to support the studio (whose revenues went to zero almost immediately). Lots of work for the studio technologist (me) to do both in terms of physical hardware, as well as online work as we transitioned away from in person classes.

Eventually, we followed our peers, teaching virtual classes via the Zoom platform. More tech work for me – setting up a zoom station at the studio as well as at home.

My home yoga room zoom set-up (left) is also handy to watch online concerts.
The studio zoom cart (right) is perhaps the 3rd iteration of the tech – with a wifi extender, on board lights, multiple cameras and a USB microphone. We can roll it anywhere!

Once the weather warmed up, we took our show on the road, teaching 7-8 outdoor classes each week. We’ve been doing free WHY in the Parks classes for many years through the local town Parks & Rec – now we ratcheted it up, with mandatory registration (to limit capacity and facilitate contact tracing), providing for donations and paid classes. We’d get up to 100 people at some classes. Opportunities for the studio techie to set up a second battery powered speaker, to figure out a way to daisy-chain (left / right speakers for larger classes), and to manage multiple wireless headsets. Oh yeah, and haul out the trusty iPad for some time-lapse videos!

Long terms, we knew that we’d be back teaching live classes, albeit capacity limited and socially distanced, so I started to build up some technology competence. I found a low cost video switcher, and some low cost HDMI cameras (think glorified security cams) and cobbled together a four camera set up that we used first for in-studio zoom classes and eventually to capture live classes.

Left: iPad confidence / stream monitor (what the end user sees)
Center: Laptop zoom computer
Right: Preview monitor and Blackmagic ATEM Mini video switcher
AIDA HD-100A cameras with Arducam lenses – top is the wide shot, bottom is the close shot. We’ve got two other cameras off to the side. HDMI cables + 12V power run into the studio office / control area.

We started with a temporary setup to prove concept and technology (HDMI cables on the floor, cameras on tripods or clamped to carts) – eventually moving to a permanent, four camera installation. You can see the end result on the studio Vimeo page here – https://vimeo.com/westhartfordyoga

Kicking It Old School

My Christmas present to myself this year – a 1974 Gottlieb Duotron pinball machine, courtesy of a local shop that once upon a time rented, sold, and serviced pool tables, juke boxes, and pinball / arcade games, but has transitioned to a warehouse full of relics and a small business in refurbing and selling old games.

Truth be told I’ve been virtually tire-kicking games for a while now – via Facebook Marketplace and Craigslist. I knew I was serious when I took down a folding table that had become a catch-all rather than a work space, replacing it with two shelving units – leaving plenty of space in my basement office for a game. And while I was a bit concerned with dissassembly, transport, and reassembly, the shop offered delivered and set-up. Sold….

The game was mostly working, with some small issues, so I’ve spent the last few weeks cleaning, tweaking, updating. Burned out bulbs, a few functions not working properly, replacing the rubber rings / elastics and some faded plastic bits. etc. It’s all up and running!

There is a significant industry out there for information and supplies. I was able to purchase a schematic and manual from an authorized source. I bought a kit of rings / rubbers curated for this machine as well as pop bumper caps. I purchased a spares kit (blubs, fuses, a new pinball, cleaner and polisher) and some LED lamps (to judiciously replace the incandescent bulbs, especially in the back box where the lamps tend to heat / damage the backglass artwork. I even found a site that recreates the instructions and replay / award cards so familiar to those who have played.

And, as an old school engineer who has been around long enough to have played this game new, and knows my way around a schematic, but never did a lot of work with relay / ladder logic, the game is an opportunity to break out a multimeter, jumper cables, and do some serious troubleshooting.

The ingenuity and complexity of these beast is amazing – stepper units to add bonus points, count players, track first and last balls, scoring reels, a motor with cams to trigger relays periodically. The Tilt devices alone are amazing.

So yeah, Merry Christmas to me. Something for an electrical engineer who does far too little engineering or troubleshooting work these days to mess around with!

The Shoemaker’s Children Go Barefoot (no more)

For someone who makes the bulk of her income working with power quality, my own computer systems have been fairly under-protected for many years.

I picked up a stand-by UPS (APC Model ES550) many years ago (maybe 10? hard to say, might have been my second device); it has served me reasonably well. And even though I’m well aware of the nature of stand-by UPS (time delay before inverter switches on, step wave inverter output) it’s done a pretty solid job of keeping my computer up and running.

A few days ago, my home office lost power for a bit – clocks were reset, the computer switched off – and I realized it was time to upgrade the office UPS. I picked up another APC – a line interactive, sine wave output model RS 1000MS – rated for 1000VA / 600W.

It’s got plenty of juice for my needs – sitting at about 20% of load / 37 minutes of battery time with my desktop, monitor, cable modem, and a small backup server and peripheral hard drive. I’m much enamored with the front panel LED screen and the PowerChute software. And while I have not set my computer up to hibernate at the command of the UPS, that’s a possibility.

I go back a long ways – when a buck a watt was perhaps a reasonable price to pay for a small UPS. So to get all this for about $150 – well, I’m not complaining.

And I took the time to run my house cable through the internal TVSS and the Ethernet from the cable modem back to the computer through the UPS – so I’ve got a better chance of surviving nearby lightning strikes / transients – related to both transient voltages and ground potential issues. I’m not at the point of driving a ground rod and connecting an external ground though. I’m down in a basement and close to the residence service panel, so not super worried about ground issues.

And I’ve also spent some time separating critical loads (computer, monitor, cable modem, exterior drives / servers) from less critical loads (printers, speakers), plugging these latter into the TVSS only outlets. And while I was down there with the system off, I spent some time untangling the cable spaghetti, wrapping and tying off cables, neatening things up.

Saying Good-bye to an Old & Loyal Friend

Not a long, emotional post (I’ve saved those for my personal blog and for social media) but I want to note the passing of my beloved canine buddy, Elo. He lived a good long doggie life of 16 years. Some clients may have heard him in the background during phone calls – he was my shadow and wherever I was in the house / office, he followed.

Elo came into my life way back in 2004; he moved with me to my present residence in 2010, and we’ve been a bonded pair ever since. He never had a lot of dog friends (being part Aussie Cattle Dog / Heeler, he was super bossy and would want to herd them) but was a great people dog. I was a little concerned how he’d transition to condo life (having come from a single family house with a fenced in yard) but he did great.

I miss the little f*cker (a pet name, well earned) a lot, although I’m happy to finally have the opportunity to get ahead of the dog hair and shedding.