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Controlling a Raspberry PI I/O pins via web App
by steve-ALUG＠hst.me.uk 12 Oct '17

12 Oct '17

Can any Raspberry Pi users out there or web people help? I Want to use webpage to control Neopixels plugged into a Raspberry Pi. The webpage will have slider controls for R, G, B & overall brightness. I was initially thinking of using cgi-bin scripts using python, but I want the colour to change as the slider moves so I don't know if that would be responsive enough. Reading around, there seem to be many python-based solutions* so I could use cgi scripts, web sockets, webpy, flask, danjo or others. Anyone got a recommendation of which way to go. Lightweight and no security will do. *I want to use python if possible as that's what I'm most familiar with ATM, with a bit of Javascript as required. Any advice appreciated. Steve

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Ubuntu 17.04 sleeping?
by Clark, Adrian F 12 Oct '17

12 Oct '17

Hello everyone, I have a machine running Ubuntu 17.04 (desktop version) on a Dell Optiplex 5050 which needs to run a long shell script (doing some machine learning runs) overnight. I've turned off suspend via Unity's "power management" control panel but it looks as though the machine still goes to sleep after being left alone for an hour. I wonder if anyone has any suggestions as to what's going on? ..Adrian -- Dr Adrian F Clark WEB: http://privatewww.essex.ac.uk/~alien/ EMAIL: alien/at/essex.ac.uk TEL: +44 1206 872432 RADIO: M0PDF PAPER: Comp Sci & Elec Eng, University of Essex, Colchester, CO4 3SQ, UK "The great tragedy of science: the slaying of a beautiful hypothesis by an ugly fact" -- Huxley

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Controlling a Raspberry PI I/O pins via web App
by Martyn Smith 12 Oct '17

12 Oct '17

I rarely comment on here so I hope I have responded correctly? I have a Pi but I have done very little with python. However, as for a web app solution - although I use C#, PHP (and some Scheme) I would probably be tempted to use web2py if encouraged to use python. Failing that - use something rather popular like Django. Please note that this below is an example. I have *not *tested it (or even downloaded web2py) but I hope this serves as an example for what, I believe, you are trying to accomplish. This code is based on general experience and what the web2py tutorials cover. The only area that needs additonal attention is ensuring the sliders are loaded with the correct values, which I have not done. However, using jquery, I have created an ajax post when the user 'mouse up' on the slider - the values are passed over (which the data variable 'should' be storing in the slider function. again - expect a few hiccups. Hope this helps. *Controller - controls.py* def slider() data = request.post_vars # Do raspberry Pi stuff here # .. or, if not, send to 'some queue' to be processed elsewhere *View - controls/slider.html* <html> <head> <title>Brightness controls</title> <meta charset="utf-8"/> <script src=" https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script> </head> <body> <form method="post" action="/controls/slider"> <input id="brightnessR" type="range" min="0" max="100" step="5" /> <input id="brightnessG" type="range" min="0" max="100" step="5" /> <input id="brightnessB" type="range" min="0" max="100" step="5" /> </form> <script type="text/javascript"> function update() { alert("updating"); $.post('/controller/method', { red: $("#brightnessR").val(), green: $("#brightnessG").val(), blue: $("#brightnessB").val() }); } $(document).ready(function() { $("#brightnessR").mouseup(update); $("#brightnessG").mouseup(update); $("#brightnessB").mouseup(update); }); </script> </body> </html>

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[ALUG Announce] ALUG Norwich Pub Meet Thursday 12th October
by Viperfang 11 Oct '17

11 Oct '17

ALUG Announce Please send announcements to Announce(a)lists.alug.org.uk Unsub, change settings via https://lists.alug.org.uk/mailman/listinfo/announce ----- Hello Norwich Aluggers, Our monthly ALUG Norwich social meeting will be held this Thursday, 12th October at The Coach and Horses (82 Thorpe Road, Norwich, NR1 1BA). The meeting officially starts at 8pm, although some people may arrive earlier. More information on those people can be found on the list and the IRC channel. If you are unsure if you will recognise us then make yourself and your intent to attend known by either posting on list or visiting us on IRC so we can look out for you rather than hiding in the corner. Optionally you could ask at the bar if they know where the geeky computer weirdos are and they'll point you in the right direction (seriously!). Another possibility is look for heaps of electronics on a table that may possibly look like movie props that would used for detonating explosives. Feel free to bring electronics/laptops/gadgets to the meet, you will by no means be alone. Ben Bewick aka Viperfang NB: This mail is automated, please refer to the usual sources for more information. ALUG Contact Details: Website : http://www.alug.org.uk/ IRC : #alug on irc.alug.org.uk List : http://lists.alug.org.uk/mailman/listinfo Twitter : http://twitter.com/anglianlug Identica: TBA Facebook: http://www.facebook.com/group.php?gid=2381613902 ----- Send discussion replies to main(a)lists.alug.org.uk (Reply-To set) Unsub, change settings via https://lists.alug.org.uk/mailman/listinfo/announce

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calendar and Nextcloud
by Phil Thane 06 Oct '17

06 Oct '17

I did it a disservice earlier, installing the upgrade of Nextcloud to version 10.*.* doesn't actually remove the calendar and contacts apps, it just disables them re-enabling them restores them without loss of data. Hopefully this manual upgrade is a one-off and in future the automagical system will work. -- Phil Thane www.pthane.co.uk phil(a)pthane.co.uk 01767 449759 07582 750607 Twitter @pthane

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Calendar server recommendations wanted
by Chris Green 06 Oct '17

06 Oct '17

I've been using OwnCloud for a few years but it really is becoming a bit of a pain to support. Well, it always *was* a pain to support and now I'm getting fed up with maintaining it. There's all sorts of (minor, but they add up) issues with it:- Upgrading is a pain, doesn't "just work". Various messages aboout security which don't link to anywhere useful. Basic Calendar and AddressBook apps aren't built-in, have to be re-enabled at each upgrade. Just messy generally! So I'm considering alternatives. I need a calendar server which supports Linux (Thunderbird/Lightning) and Android clients, if it does address lists as well then so much the better but that's not vital. Any recommendations anyone? -- Chris Green

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2600 meeting at 18:00 on Friday the 6th October.
by Viperfang 03 Oct '17

03 Oct '17

Quick heads up about this months Norwich 2600 meeting, more info at http://www.norwich2600.co.uk

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Manipulating files from bash
by Mark Rogers 25 Sep '17

25 Sep '17

There are lots of ways to process text files (eg sed, awk, etc); I'm after suggestions on the best/easiest way to achieve something fairly trivial to describe. Below is example output from sfdisk -d: label: dos label-id: 0xe3f4f21a device: /dev/sdd unit: sectors /dev/sdd1 : start= 8192, size= 85622, type=c /dev/sdd2 : start= 94208, size= 5521408, type=83 /dev/sdd3 : start= 5615616, size= 25499648, type=83 I want to convert this into a new script to go back into sfdisk but with some changes; I want the start values skipped (so sfdisk will put partition boundaries wherever it thinks is best), I want the last sector not have a size (ie "rest of disk"), and I don't really need any of the settings at the top. In fact, a suitable (minimal) script to go into sfdisk would be simply: ,85622,c ,5521408 ,; I don't really mind at this point whether I end up with something more like the first format or minified like the latter. In fact to be honest I'm more interested just in learning the best ways to play with text files like this. -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 1450 Registered in England (0456 0902) 21 Drakes Mews, Milton Keynes, MK8 0ER

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RPi SD backup/restore
by Mark Rogers 25 Sep '17

25 Sep '17

I've been experimenting with backing up and restoring Raspberry Pi SD cards. There is of-course a very easy way: use "dd" or similar to create a disk image. However it has three disdvantages; it is slow, and it creates very large backups. And it's hard to extract individual files from the backups. I've written up a quick process [1] for doing it manually, which is essentially: 1. Backup (or restore) the partitions using sfdisk 2. (Restore only) Create the filesystems on the destination 3. Backup (or restore) the files using tar. However I'd like some advice on scripting and improving it. In particular, this process creates three files (one for the partition info, and one each for the files from the two partitions). I'd like to end up with a single file, which I can do by just tar'ing the three at the end, but given the size of the files I want to keep the use of temporary files to a minimum. Also, at the moment it's quite inflexible in terms of restoring to a different sized card, but ought not be. But regardless, I figured there'd be enough Pi users around here who might find it useful. (Use at your own risk, it's had very limited testing so far.) [1] https://docs.google.com/document/d/e/2PACX-1vRk_zldu0Ra6MEEepTSKCzD55ANeasQ… -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 1450 Registered in England (0456 0902) 21 Drakes Mews, Milton Keynes, MK8 0ER

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Disk labels and partition names
by Mark Rogers 22 Sep '17

22 Sep '17

In my experiments with RPi backups, I note that the SD card has a label and that label is used when the partitions are mounted (eg disk label: 0xbff5ebb9, and /etc/fstab using PARTUUID=bff5ebb9-01 and bff5ebb9-02). Is it better that I (a) change my fstab to mount by partition name (/dev/sda1, /dev/sda2) and let the disk labels vary when duplicating across multiple Pi's, or (b) leave fstab to use the disk label and leave it the same across multiple Pi's? There's also option (c) which is to generate a new disk label but update fstab accordingly on restore. I'd rather avoid that unless there's a convincing argument for it though. I guess what I'm asking is how much it matters if lots of Pi's have the same disk label, and also weighed against that how much it is an advantage to mount based on disk ID instead of partition number. Mark -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 1450 Registered in England (0456 0902) 21 Drakes Mews, Milton Keynes, MK8 0ER

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