planet.donarmstrong.com

The Tom Clancy book Debt of Honor published in August 1994 first introduced the concept of a heavy passenger aircraft being used as a weapon by terrorists against a well defended building. In April 1994 there was an attempt to hijack and deliberately crash FedEx flight 705. It’s possible for a book to be changed 4 months before publication, but it seems unlikely that a significant plot point in a series of books was changed in such a small amount of time so it’s likely that Tom Clancy got the idea first. There have been other variations on that theme, such as the Yokosuka_MXY-7 Kamakazi flying bomb (known by the Allies as “Baka” which is Japanese for idiot). But Tom Clancy seemed to pioneer the idea of a commercial passenger jet being subverted for the purpose of ground attack.

7 years after Tom Clancy’s book was published the 911 hijackings happened.

The TV series Black Mirror first aired in 2011, and the first episode was about terrorists kidnapping a princess and demanding that the UK PM perform an indecent act with a pig for her release. While the plot was a little extreme (the entire series is extreme) the basic concept of sexual extortion based on terrorist acts is something that could be done in real life, and if terrorists were inspired by this they are taking longer than expected to do it.

Most democracies seem to end up with two major parties that are closely matched. Even if a government was strict about not negotiating with terrorists it seems likely that terrorists demanding that a politician perform an unusual sex act on TV would change things, supporters would be divided into groups that support and oppose negotiating. Discussions wouldn’t be as civil as when the negotiation involves money or freeing prisoners. If an election result was perceived to have been influenced by such terrorism then supporters of the side that lost would claim it to be unfair and reject the result. If the goal of terrorists was to cause chaos then that would be one way of achieving it, and they have had over 10 years to consider this possibility.

Are we overdue for a terror attack inspired by Black Mirror?

For a while now, I’ve been looking for a good way to stream music from my home music collection on my phone.

There are quite a few options for music servers that support streaming. However, Android apps that can stream music from one of those servers tend to be unmaintained, clunky or slow (or more than one of those).

It is possible to use something that runs in a web server, but that means no offline caching - which can be quite convenient in spots without connectivity, such as the Underground or other random bits of London with poor cell coverage.

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apiVersion: apps/v1
kind: Deployment
metadata:
 name: navidrome
spec:
 replicas: 1
 selector:
   matchLabels:
     app: navidrome
 template:
   metadata:
     labels:
       app: navidrome
   spec:
     containers:
       - name: navidrome
         image: deluan/navidrome:latest
         imagePullPolicy: Always
         resources:
           limits:
             cpu: ".5"
             memory: "2Gi"
           requests:
             cpu: "0.1"
             memory: "10M"
         ports:
           - containerPort: 4533
         volumeMounts:
           - name: navidrome-data-volume
             mountPath: /data
           - name: navidrome-music-volume
             mountPath: /music
         env:
           - name: ND_SCANSCHEDULE
             value: 1h
           - name: ND_LOGLEVEL
             value: info
           - name: ND_SESSIONTIMEOUT
             value: 24h
           - name: ND_BASEURL
             value: /navidrome
         livenessProbe:
            httpGet:
              path: /navidrome/app
              port: 4533
            initialDelaySeconds: 30
            periodSeconds: 3
            timeoutSeconds: 90
     volumes:
        - name: navidrome-data-volume
          hostPath:
           path: /srv/navidrome
           type: Directory
        - name: navidrome-music-volume
          hostPath:
            path: /srv/media/music
            type: Directory
---
apiVersion: v1
kind: Service
metadata:
  name: navidrome
spec:
  ports:
    - port: 4533
      name: web
  selector:
    app: navidrome
  type: ClusterIP

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apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: navidrome
spec:
  ingressClassName: nginx
  rules:
  - host: example.com
    http:
      paths:
      - backend:
          service:
            name: navidrome
            port:
              name: web
        path: /navidrome(/|$)(.*)
        pathType: Prefix

Previously I setup a CC2531 as a Zigbee coordinator for my home automation. This has turned out to be a good move, with the 4 gang wireless switch being particularly useful. However the range of the CC2531 is fairly poor; it has a simple PCB antenna. It’s also a very basic device. I set about trying to improve the range and scalability and settled upon a CC2538 + CC2592 device, which feature an MMCX antenna connector. This device also has the advantage that it’s ARM based, which I’m hopeful means I might be able to build some firmware myself using a standard GCC toolchain.

For now I fetched the JetHome firmware from https://github.com/jethome-ru/zigbee-firmware/tree/master/ti/coordinator/cc2538_cc2592 (JH_2538_2592_ZNP_UART_20211222.hex) - while it’s possible to do USB directly with the CC2538 my board doesn’t have those bits so going the external USB UART route is easier.

The device had some existing firmware on it, so I needed to erase this to force a drop into the boot loader. That means soldering up the JTAG pins and hooking it up to my Bus Pirate for OpenOCD goodness.

source [find interface/buspirate.cfg]

buspirate_port /dev/ttyUSB1
buspirate_mode normal
buspirate_vreg 1
buspirate_pullup 0

transport select jtag

source [find target/cc2538.cfg]

$ telnet localhost 4444
Trying ::1...
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
Open On-Chip Debugger
> mww 0x400D300C 0x7F800
> mww 0x400D3008 0x0205
> shutdown
shutdown command invoked
Connection closed by foreign host.

At that point I can switch to the UART connection (on PA0 + PA1) and flash using cc2538-bsl:

$ git clone https://github.com/JelmerT/cc2538-bsl.git
$ cc2538-bsl/cc2538-bsl.py -p /dev/ttyUSB1 -e -w -v ~/JH_2538_2592_ZNP_UART_20211222.hex
Opening port /dev/ttyUSB1, baud 500000
Reading data from /home/noodles/JH_2538_2592_ZNP_UART_20211222.hex
Firmware file: Intel Hex
Connecting to target...
CC2538 PG2.0: 512KB Flash, 32KB SRAM, CCFG at 0x0027FFD4
Primary IEEE Address: 00:12:4B:00:22:22:22:22
    Performing mass erase
Erasing 524288 bytes starting at address 0x00200000
    Erase done
Writing 524256 bytes starting at address 0x00200000
Write 232 bytes at 0x0027FEF88
    Write done
Verifying by comparing CRC32 calculations.
    Verified (match: 0x74f2b0a1)

I then wanted to migrate from the old device to the new without having to repair everything. So I shut down Home Assistant and backed up the CC2531 network information using zigpy-znp (which is already installed for Home Assistant):

python3 -m zigpy_znp.tools.network_backup /dev/zigbee > cc2531-network.json

I copied the backup to cc2538-network.json and modified the coordinator_ieee to be the new device’s MAC address (rather than end up with 2 devices claiming the same MAC if/when I reuse the CC2531) and did:

python3 -m zigpy_znp.tools.network_restore --input cc2538-network.json /dev/ttyUSB1

The old CC2531 needed unplugged first, otherwise I got an RuntimeError: Network formation refused, RF environment is likely too noisy. Temporarily unscrew the antenna or shield the coordinator with metal until a network is formed. error.

After that I updated my udev rules to map the CC2538 to /dev/zigbee and restarted Home Assistant. To my surprise it came up and detected the existing devices without any extra effort on my part. However that resulted in 2 coordinators being shown in the visualisation, with the old one turning up as unk_manufacturer. Fixing that involved editing /etc/homeassistant/.storage/core.device_registry and removing the entry which had the old MAC address, removing the device entry in /etc/homeassistant/.storage/zha.storage for the old MAC and then finally firing up sqlite to modify the Zigbee database:

$ sqlite3 /etc/homeassistant/zigbee.db
SQLite version 3.34.1 2021-01-20 14:10:07
Enter ".help" for usage hints.
sqlite> DELETE FROM devices_v6 WHERE ieee = '00:12:4b:00:11:11:11:11';
sqlite> DELETE FROM endpoints_v6 WHERE ieee = '00:12:4b:00:11:11:11:11';
sqlite> DELETE FROM in_clusters_v6 WHERE ieee = '00:12:4b:00:11:11:11:11';
sqlite> DELETE FROM neighbors_v6 WHERE ieee = '00:12:4b:00:11:11:11:11' OR device_ieee = '00:12:4b:00:11:11:11:11';
sqlite> DELETE FROM node_descriptors_v6 WHERE ieee = '00:12:4b:00:11:11:11:11';
sqlite> DELETE FROM out_clusters_v6 WHERE ieee = '00:12:4b:00:11:11:11:11';
sqlite> .quit

So far it all seems a bit happier than with the CC2531; I’ve been able to pair a light bulb that was previously detected but would not integrate, which suggests the range is improved.

(This post another in the set of “things I should write down so I can just grep my own website when I forget what I did to do foo”.)

Recently a relative who owned a 50″ Plasma TV asked me for advice on getting a new TV. Looking at the options all the TVs seem to be smart TVs (running Android with built in support for YouTube and Netflix) and most of them seem to be 4K resolution. 4K doesn’t provide much benefit now as most people don’t have BlueRay DVD players and discs, there aren’t a lot of 4K YouTube videos, and most streaming services don’t offer 4K resolution. But as 4K doesn’t cost much more it doesn’t make sense not to get it.

I gave my relative a list of good options from Kogan (the Australian company that has the cheapest consumer electronics) and they chose a 65″ 4K Smart TV from Kogan. That only cost $709 plus delivery which is reasonably affordable for something that will presumably last for a long time and be used by many people.

Netflix on a web browser won’t do more than FullHD resolution unless you use Edge on Windows 10. But Netflix on the smart tv has a row advertising 4K shows which indicates that 4K is supported. There are some 4K videos on YouTube but not a lot at this time.

Size

It turns out that 65″ is very big. It didn’t fit on the table that had been used for the 50″ Plasma TV.

Rtings.com has a good article about TV size vs distance [1]. According to their calculations if you want to sit 2 meters away from a TV and have a 30 degree field of view (recommended for “mixed” use) then a 45″ TV is ideal.

According to their calculations on pixel sizes, if you have a FullHD display (or the common modern case a FullHD signal displayed on a 4K monitor) that is between 1.8 and 2.5 meters away from you then a 45″ TV is the largest that will be useful. To take proper advantage of a monitor larger than 45″ at a distance of 2 meters you need a 4K signal. If you have a 4K signal then you can get best results by having a 45″ monitor less than 1.8 meters away from you. As most TV watching involves less than 3 people it shouldn’t be inconvenient to be less than 1.8 meters away from the TV.

The 65″ TV weighs 21Kg according to the specs, that isn’t a huge amount for something small, but for something a large and inconvenient as a 65″ TV it’s impossible for one person to safely move. Kogan sells 43″ TVs that weigh 6KG, that’s something that most adults could move with one hand. I think that a medium size TV that can be easily moved to a convenient location would probably give an equivalent viewing result to an extremely large TV that can’t be moved at all. I currently have a 40″ LCD TV, the only reason I have that is because a friend didn’t need it, the previous 32″ TV that I used was adequate for my needs. Most of my TV viewing is on a 28″ monitor, which I find adequate for 2 or 3 people. So I generally wouldn’t recommend a 65″ TV for anyone.

Android for TVs

Android wasn’t designed for TVs and doesn’t work that well on them. Having buttons on the remote for Netflix and YouTube is handy, but it would be nice if there were programmable buttons for other commonly used apps or a way to switch between the last few apps (like ALT-TAB on a PC).

One good feature of Android for TV is that it can display a set of rows of shows (similar to the Netflix method of displaying) where each row is from a different app. The apps I’ve installed on that TV which support the row view are Netflix, YouTube, YouTube Music, ABC iView (that’s Australian ABC), 7plus, 9now, and SBS on Demand. That’s nice, now we just need channel 10’s app to support that to have coverage for all Australian free TV stations in the Android TV interface.

Conclusion

It’s a nice TV and it generally works well. Android is OK for TV use but far from great. It is running Android version 9, maybe a newer version of Android works better on TVs.

It’s too large for reasonable people to use in a home. I’ve seen smaller TVs used for 20 people in an office in a video conference. It’s cheap enough that most people can afford it, but it’s easier and more convenient to have something smaller and lighter.

• [1] https://www.rtings.com/tv/reviews/by-size/size-to-distance-relationship

I have recently signed up for the Curiosity Stream [1] documentary site, this is designed to be like Netflix but for non-fiction content only. The service costs $US15 per annum or $52US per annum for 4K (I think the 4K service was about $US120 per annum when I signed up). The extra price for 4K seems excessive, while it is in line with the bandwidth requirements a large portion of the costs of the service would be about user support and running the service reliably for which 4K makes little difference.

My aim in subscribing was to just get a service like Netflix with new documentary content as I have watched every documentary I want to watch on Netflix (I think I’ve watched over 1000 hours of Netflix documentaries). So naturally I compare the service to Netflix and I found that it doesn’t compare well. Curiosity Stream (CS) has no button to skip the intro and has a problem with using the right arrow to skip forward (seems to only work once and then I have to use the mouse), this costs me about 30 seconds for each episode which adds up when watching documentaries at 1.5* speed. The method of controlling the viewing is a little clunky, sometimes the popup menu at the bottom of the screen to control playback doesn’t disappear by itself until you mouse over it and space bar doesn’t select pause instead it selects the last action. CS allows selecting individual episodes for your watch list instead of entire series, this could be useful for some people but I just find it annoying, it might be good for classroom use. The method of searching for new shows to watch isn’t as good as the Netflix method or the way things are displayed on Android TV (which seems to have an API for multiple video providers to show a list of shows with one row per provider). Some of these things might seem OK if you haven’t used other services, but if you are used to Netflix and Amazon Prime then it will seem clunky.

The amount of content on Curiosity Stream doesn’t seem that large, I don’t know how to get a full measure of it, but when I search for things I seem to get less results than on Netflix. That could be something to do with what I’m searching for.

In terms of value for money $US15 per annum for the content that CS provides is a good deal. Netflix overall offers better value for home users having fiction as well as non-fiction in large quantities. But for documentary content $US15 per annum is pretty cheap. I recommend signing up for CS, but for most people signing up for Netflix first will be a good option.

1. [1] https://curiositystream.com/