Virtual cameras in Zoom and Teams

 Just leaving this here to remind me how to get Teams to work with an OBS virtual camera again after an update: 

*****UPDATE*****

As of version 1.3.00.28778 the process has changed and the above workaround is no longer valid.  In order to get this fix working on the latest version of Teams, additional commands will need to be entered.  Keep in mind, these commands are relative to where you have Teams installed, so if it is in a different location, you'll need to adjust the file path accordingly.  So as it stands currently here are all of the commands (must be entered one by one and not pasted in one big block) that will need to be entered:

xcode-select --install (only if you haven't already)

sudo codesign --remove-signature "/Applications/Microsoft Teams.app"

sudo codesign --remove-signature "/Applications/Microsoft Teams.app/Contents/Frameworks/Microsoft Teams Helper.app"

sudo codesign --remove-signature "/Applications/Microsoft Teams.app/Contents/Frameworks/Microsoft Teams Helper (GPU).app"

sudo codesign --remove-signature "/Applications/Microsoft Teams.app/Contents/Frameworks/Microsoft Teams Helper (Plugin).app"

sudo codesign --remove-signature "/Applications/Microsoft Teams.app/Contents/Frameworks/Microsoft Teams Helper (Renderer).app"

Lockdown Loaf

 So, I decided during this kind of lockdown that I would have a go at breadmaking. I'd ordered up the ingredients from Sainsbury's last week just in case i felt like it. 

For today, I had put a casserole in the slow cooker this morning and I jiust fancied some olive bread to go with it, so I decided to make some. Here's my first effort at a loaf ...

New lab has a new iMac

 Well, new to me anyhow. Working all day on a small Macbook (though I love it for performance and battery life) is bad for the eyes, so I have furnished the lab with a pre-loved iMac 27 inches ... 

Access to the Lab is now improved ...

So instead of walking across a series of stepping stones embedded in mud, we now have some proper decking outside the lab. It is huge. Well done, Kris - it really does look spectacular. After this, the next steps will be some tidying up at the bottom, and the rockery / wild garden / pond .. looking forward to some post lock-down family gatherings here.

Fixed the Cambridge P500

Another one off the list of things to sort out .. turned out to be one of the darlington output transistors. They have integrated emitter resistors, and one had gone from 0.22 ohm to something in the hundreds of ohms, so it got replaced. While I was there I checked all the caps (no problems) and I replaced all of the heat sink compound, as there was pretty much none on the transistor I changed. Actually I changed both on that channel to make sure I had a matching pair. Applied power, and success! Sound in both.

There's quite a lot of discussion on t'Internet about the bias current, but I found in the spec for the trannys themselves that they recommend 40mA. So I put some meters on, looking for 17.6mV across the two 0.22 ohm resistors. They seemed to want to settle at 20.4mV which is close enough.

This is a budget amp, so I wasn't expecting too much, but the heatsink is a bit pissy and it feels cheap. The whole amp is not worth saving, really but it might do for a bench amp at a push. At least it is now off my bench so I can move on down the list of things to be repaired.

Changing HDD to SSD in an iMac

For a friend; I volunteered to change the hard disk to an ssd in a 2012 iMac. Well, doesn't sound too difficult, does it? I mean, how difficult can it be?

First, there is the getting in to the thing in the first place. It involved delicate prying of the screen away from the back, using guitar picks and a scalpel (very, very gently) to cut through the glue. It fought back, so I did what most people do and went to Youtube for guidance. The main thing seemed to be get it warm with a hair dryer. So, being a very hot May Day, I left the thing out in the sun for three hours to get nice and toasty inside and out.

This got me to the point where the scalpel and guitar picks started to work, and a suction cup gently pulling the front eventually got it to give way ..

So the next step is to fit the SSD in the hole where the old HD was. Now, the old HDD looks like this:

.. and the new one is too small. 

So it's off to Amazon to order up a converter. The first one wasn't the right style to fit into an iMac despite all of the promises on the web site, so I had to have another go. I also ordered up the sticky strips designed to work in an iMac to put the thing back together again. 

All done .. restoring from a Time Machine backup, only took 12 hours for 2TB of data. That has to be quite fast, but clearly benefiting from the fusion drive it was coming from as well. 

Look, Heidi - I have 27 Inches Of Loveliness in the Lab! - if only temporarily ...

Warm weather, and the Nixie clock is suddenly very accurate

My Nixie clock in the Lab is suddenly maintaining time to the second. It's controlled by a crystal, and always has run a little bit fast since I never got around to putting a trimmer cap on it. Now I know that crystals age; the mechanical stress it is under when mounted relaxes over time; purities move within the crystal, and the crystal itself might lose a bit - or gain a bit of mass as crap floats around. It's not oven controlled or anything - just room temperature controlled, and now, it's fantastic.

I was talking about replacing it and building a new one. I wonder if it heard me?

By the way ...

I am now

0x40

years old

First up, does the Lab need another name?

So when Kris was kindly constructing my home office, it clearly wasn't going to be an ordinary home office. I'm very proud of the results, including the way it's been wired up. (though I have to find the wires for the rear speakers which are routed to behind the big TV screen, and I need to get them to the fine Denon 3803 amp). All just in time for a pandemic to reduce us all to working from home.

What troubled me for a while, was what to call it. When I first got kicked out of the fourth bedroom
in Winsford Close, I moved into the rear of the garage. Most people have a garage which is never darkened with a car in the UK - ordinary folks, if they are lucky enough to have a garage don't have one where you can drive in and open the doors without dents. They fill up with gardening stuff, bits of old bikes, your fishing gear and golf clubs, and several incomplete sets of drain rods. (the missing sections having been left in drains in former residences).

So anyway, I partitioned off a half of the garage, and set up some work benches, a few computers and a modest sound system. Wired to the rest of the house via thin ethernet (gasp!) I could leave a server in there running the house file system and so on. And that's where the handle "niksgarage" came from. It replaced the name I used before, which was "niks42", which I used a lot when I was single again, as a short cut to those first questions on a bulletin board a/s/l ?

I wired the house for internet, shared out through a smoothwall box with a frog modem on it:-

The famed Alcatel Speedtouch USB ADSL modem, running at a cool 500K bits/second (a huge leap up from the 56k modem).

So that's why this, my new location, being all posh, custom designed and made is not my garage - besides, there is also a garage. And a shed, for Trish's stuff and garden tools.

Studio sounds too pretentious. (though I do have a machine called studio, which runs the music software).

Also, an office sounds too square.

stu·di·o

Noun:

A room where an artist, photographer, sculptor, etc., works

of·fice

Noun:

A room, set of rooms, or building used as a place for commercial, professional, or bureaucratic work.

So, in due deference to both the company name of Hayling Island Laboratories Ltd - itself a pun on IBM UK Laboratories Ltd at Hursley Park, my alma mater, this is now my lab. 

lab

Noun:

A laboratory: "a science lab" So, come up to the lab,  and see what's on the slab. I see you shiver with antici ... pation.

.. and I forgot to mention the subwoofer project

I also have a Peerless 850140 25cm drive unit for a subwoofer. I have only had it about 19-20 years, in a box with a plastic port tube and a bundle of wadding. I now also have a collection of amplifiers ready to go, and I have a suitable 6dB/octave filter that I can use to make sure it doesn't get overcooked by higher frequencies.

So I really should bring all of those bits together, along with a 30-0-30 toroid, some 4700uF 63v nice capacitors, bridge rectifier and a suitably large heatsink and let's see if we can make the Lab reverberate.

TBS8922 on Liberator

So I think the clue is in the top line:

[   25.228598] cx88xx: subsystem: 8922:8888, board: NotOnlyTV LV3H [card=91,insmod option]

It would seem that the card is not being identified correctly, so when it comes to loading the firmware, that succeeds but is probably the wrong code for the board. Hence when the DVB bit tries to load, nothing happen.

I'm currently using the TBS recommended open source fork of their own driver, so I have the source code tree. The code that looks after the bring-up of the card is in their source code tree, somewhere in tbsdriver/media_build/v4l/.

It would seem that it is somewhere in cx88-dvb.c that this all goes horribly wrong. That file embeds cx88.h which has the definitions of all of the boards:

#define CX88_BOARD_NOTONLYTV_LV3H          91
#define CX88_BOARD_TBS_8922                92

Ah, so somehow the code misses the correct board. I wonder if there is a way of enforcing the correct board when the machine boots ? 

So, after a bit more hacking and installing different versions of the software, and remembering to "make clean", or sometimes destroying the entire source code tree, I am now at the stage of: 

niks@liberator ~ $ dmesg | grep cx88
[   27.332697] cx88xx: subsystem: 8922:8888, board: TurboSight TBS 8922 DVB-S/S2 [card=92,insmod option], frontend(s): 1
[   27.964969] rc rc0: cx88 IR (TurboSight TBS 8922 DV as /devices/pci0000:00/0000:00:1e.0/0000:06:01.2/rc/rc0
[   27.965042] rc rc0: lirc_dev: driver cx88xx registered at minor = 0, raw IR receiver, no transmitter
[   27.965069] input: cx88 IR (TurboSight TBS 8922 DV as /devices/pci0000:00/0000:00:1e.0/0000:06:01.2/rc/rc0/input37
[   27.965228] cx8802: cx2388x 8802 Driver Manager
[   27.965262] cx8800: found at 0000:06:01.0, rev: 5, irq: 21, latency: 128, mmio: 0xf9000000
[   27.965305] cx8802: found at 0000:06:01.2, rev: 5, irq: 21, latency: 128, mmio: 0xf8000000
[   27.965408] cx8800: registered device video2 [v4l2]
[   27.965473] cx8800: registered device vbi0
[   28.698345] cx88_dvb: cx2388x dvb driver version 1.0.0 loaded
[   28.698346] cx8802: registering cx8802 driver, type: dvb access: shared
[   28.698348] cx8802: subsystem: 8922:8888, board: TurboSight TBS 8922 DVB-S/S2 [card=92]
[   28.698348] cx88_dvb: cx2388x based DVB/ATSC card
[   28.698349] cx88_dvb: cx8802_alloc_frontends: allocating 1 frontend(s)
[   29.317187] dvbdev: DVB: registering new adapter (cx88[0])

Happy 2020 and all that

It's very nearly Brexit time.

I have decided to retire hermit-like, troglodyte-ish into my man-cave, my secret den, my Lab. And as always there are a ton of things to sort out in here.

There's the modular synth. I've only been actively building it since 1992, so time it was more permanently enclosed, and started being used all together rather than in bits on a bench. That's one project.

I have a Cambridge P500 power amp - discrete of course, no integrated amps here. (well there is one in the Optonica 4000). Anyway the Cambridge has lost one channel - both output transistors (class B) have decided to go short. Replacements are here, just waiting for me to box it up. Actually I have paused, since the heat sink on it looks a little, well, weedy and I wondered if I should get a heatsink out of one of the dead home cinema amps I have and use that. On the other hand, I will probably only ever use the P500 to provide the output amp for the mini-studio.

There's a whole bunch of FPGA and Arduino projects on the bench. Some relate to music. I want to recreate the authentic sounds of a Hammond B3, with Leslie on an FPGA. I also have a project to do digital SP/DIF output music synthesis. And then there are the many projects based around a 16 x 16 illuminated matrix for controlling sequencers and all. There' also the mini project here that will take the video from the HP16500a logic analyser / digital scope, make it into something suitable like s-Video and send it to the Hauppauge video card in  Liberator, the main Linux box that drives all of the screens here so I can use the Logic Analyser and put the video big enough on the screen that I can see it without squinting. I have a mouse that works on the HP16500a so I don't need to use the touch screen overlay, etc.

But the first thing to fix is the DVB-S2 satellite receiver in the Lab. It's a TBS8922 card, full PCI, has been working for several years at the old house but I can't get it to work on Liberator. I have been struggling on and off for a couple of months - scarcely a priority to fix here given everything else that needed doing. Anyway, now I am at the point where it *nearly* works;

niks@liberator ~ $ dmesg | grep -i cx88
[   25.228598] cx88xx: subsystem: 8922:8888, board: NotOnlyTV LV3H [card=91,insmod option], frontend(s): 1
[   25.781804] cx8800: found at 0000:06:01.0, rev: 5, irq: 21, latency: 128, mmio: 0xf9000000
[   25.781807] cx8802: cx2388x 8802 Driver Manager
[   25.781890] cx8802: found at 0000:06:01.2, rev: 5, irq: 21, latency: 128, mmio: 0xf8000000
[   25.781996] cx8800: registered device video0 [v4l2]
[   25.782026] cx8800: registered device vbi0
[   25.782054] cx8800: registered device radio0
[   26.111299] cx88_dvb: cx2388x dvb driver version 1.0.0 loaded
[   26.111301] cx8802: registering cx8802 driver, type: dvb access: shared
[   26.111302] cx8802: subsystem: 8922:8888, board: NotOnlyTV LV3H [card=91]
[   26.111302] cx88_dvb: cx2388x based DVB/ATSC card
[   26.111303] cx88_dvb: cx8802_alloc_frontends: allocating 1 frontend(s)
[   26.368863] cx88_dvb: frontend initialization failed
[   26.368865] cx88_dvb: dvb_register failed (err = -22)
[   26.368866] cx8802: cx8802 probe failed, err = -22