Winter Maintenance 2020/21

[Penri]

Topic started to capture issues that should be addressed as part of the 2020/21 winter workshop.


"Real-time" clock controlling Minster actions is out of sync with the actual time.

Minster Pi need to be connected to the WMT network so it canoe accessed for maintenance remotely.

The currently installed speakers / sound system emitting a loud audible hum them can be heard outside the building itself, when I've witnessed it (on 2 occasions) it has not been accompanied by music. Toggling the switches didn't appear to do anything, either kill the hum or cause music to re-start. The only remedy, used on both occasions, has been to power cycle the system, this returns the system to normal operation (without hum).

[TerryJC]

Minster Pi need to be connected to the WMT network so it can be accessed for maintenance remotely.

My idea for this is to use a WiFi Adapter with an external Antenna at the end of 6 m of coaxial extension lead. I have an old Edimax WiFi Adaptor with a removable antenna that works well with the extension. I bought the extension cable some time ago (I can't remember why) but never used it. We could plug the adaptor into one of the USB ports on the Pi 3 and run the extension up to the Bell Tower (or even the roof if need be).

Once this was done, we would not only be able to change the clock; we wouldn't need to because the Pi would get it's time from the Internet via the VPN server.

The currently installed speakers / sound system emitting a loud audible hum them can be heard outside the building itself, when I've witnessed it (on 2 occasions) it has not been accompanied by music. Toggling the switches didn't appear to do anything, either kill the hum or cause music to re-start. The only remedy, used on both occasions, has been to power cycle the system, this returns the system to normal operation (without hum).

This hum seems to have been an intermittent problem since the system was originally set to work. Usually it is fairly quiet, but occasionally it is quite loud. Ideally the system should be re-engineered to provide better isolation between the sound coming out of the audio jack / USB Audio Adaptor and the rest of the electronics but that might be a hiding to nothing because the Raspberry Pi sound system is a bit naff at the best of times and the USB Adaptor for the Music isn't much better.

We could go the whole hog and put in a proper audio DAC for the music and the Rolls-Royce system would have a DAC for the Bells as well (a second Pi would be needed). Both functions could be performed with two Pi Zeros and we could retain the Pi 3 as a spare (or for the Staff / Visitor GUI). These DACs were available when we did the original system, but they were circa £50-60 each at that time, so I went for the cheaper option of using the Kemo Audio Amplifiers from Maptlin which were about £15 each and good for 12 W. The Audio DAC that I used for the Railway Room Sound Effects Player was less than £20 and comes with a display and various other useful features, including being able to control it over a network.

Here are some examples:

1. What I used in the Railway Room - 3 W Stero Amplifier DAC (https://shop.pimoroni.com/products/pira ... stereo-amp). That might be a bit quiet in that there is only 3 W per channel available. However, these DACs can be switched to mono and the second channel could be used for a new speaker in the Porch, further up the Nave.
2. This is a Lineout equivalent of the above (https://shop.pimoroni.com/products/pira ... o-line-out) that we could use with the Kemo Amps.
3. The above may be OTT for the application, because we clearly wouldn't need (or want) the screen. There are other audio DACs out there such as (https://shop.pimoroni.com/products/adaf ... i-mini-kit). Adafruit don't seem to do a Lineout equivalent.

Thoughts?

[hamishmb]

For sorting out the Minster RTC, we could sync it with the NAS box if it's to join the WMT network.

Wifi adaptor comments:

Does this happen to be an Edimax Ew-7811Un, or a similar one with an RTL8xxx chipset inside ("lsusb" will tell you on Linux)? I have had numerous issues setting one of these up to work reliably (or at all!) as a WiFi AP. I have not been able to get this to work at all as of Raspbian Buster (but it did work on a older version). I guess I'm either warning you away from this , or, if you have a working procedure, I'm interested to see it

[TerryJC]

Does this happen to be an Edimax Ew-7811Un, or a similar one with an RTL8xxx chipset inside ("lsusb" will tell you on Linux)? I have had numerous issues setting one of these up to work reliably (or at all!) as a WiFi AP. I have not been able to get this to work at all as of Raspbian Buster (but it did work on a older version). I guess I'm either warning you away from this , or, if you have a working procedure, I'm interested to see it

No it's an EW-7318USg (https://www.amazon.co.uk/EW-7318USG-Wir ... B000NNSY7K). Also, we won't be using it as a AP; just to provide network access for the Pi(s).

I used it for ages on an old laptop that I had and it always worked fine.

[hamishmb]

Should be fine if you're not using it as an AP. Worth checking with a pi at home first though - some of these tend to flake out in my experience.

Note that as this is a b/g device, if the AP it connects to is 802.11n or higher, it will probably slow everything down to 802.11g speeds.

[TerryJC]

Note that as this is a b/g device, if the AP it connects to is 802.11n or higher, it will probably slow everything down to 802.11g speeds.

Very possibly, but then so would any visitor connecting to the network with an older phone or laptop.

I think 54 Mbps is fast enough for anybody

[hamishmb]

True, true

Any ideas how many people are using it?

[TerryJC]

True, true :)Any ideas how many people are using it?

Do you mean 802.11g or the WMT WiFi? If the former then it's anyone with an older phone or laptop. If the latter, then I don't really know. WMT don't advertise the WiFi very obviously, so probably not a huge number.

[TerryJC]

I have created a new Forum to cover the Requirements, Design, Development, Installation and Maintenance of the new system, see viewforum.php?f=47. At the moment there is only one Topic; Requirements. I would appreciate comments on what I have posted.