Wiring for 1-wire sensors

[SteveH]

 Sorry for going OT...

type in 'charmap' into Start Run

 Think that only works in "Wine-doze"

Good for making secure Passwords. More here:http://www.irongeek.com/alt-numpad-ascii-key-combos-and-chart.html

 I'm out of my depth with other OS's, as I trained on DOS back in the early 80's. You can get extended character sets on other OS's but they don't tend to use  ASCII. Unix/Linux use Unicode, but a quick Search with the OS name & Unicode should find the information.

 Ubuntu uses UTF & has "Gucharmap"

 But it can be done...
 

 

[KLD]

For the Linux users: In Debian you can access unicode characters via the following key combination:

Hold Ctrl-Shift, first press U, followed by the hex code for the character.
The degree sysmbol (°) is hex 00B0, for example. It's part of the Unicode Latin-1 Supplement.  I found a how-to here (near the bottom of the page).

What a luxury having a German keyboard ;-)

Klaus

[KLD]

Sorry for dragging this up again, and then even on the OT part 

My old laptop is slowly giving up it's ghost, and after lots of faffing about I got myself a new Acer Travelmate Timeline notebook. I don't know what these designers think about, but they forgot to put a degree (°) sign on the keyboard. 

I've installed Debian, with Gnome window manager. In order to re-instate the degree key, I changed the keyboard mapping in X. It's unbelievable how well hidden the link is, between pressing a key and writing something on the screen. In short:
When X starts, it calls a config file (/etc/X11/xorg.conf). In there are defined the input and output devices. In the keyboard section it states

Code:

Option     "XkbLayout"       "gb"

The reference to kdb layout "gb" is actually to a file,  /usr/share/X11/xkb/symbols/gb . The first section reads

Code:

xkb_symbols "basic" {

    include "latin"

    name[Group1]="United Kingdom";

    key <AE02> { [         2,   quotedbl,  twosuperior,    oneeighth ] };
    key <AE03> { [         3,   sterling, threesuperior,    sterling ] };
    key <AE04> { [         4,     dollar,     EuroSign,   onequarter ] };

    key <AC11> { [apostrophe,         at, dead_circumflex, dead_caron] };
    key <TLDE> { [     grave,    notsign,          bar,          bar ] };

    key <BKSL> { [numbersign, asciitilde,   dead_grave,   dead_breve ] };
    key <LSGT> { [ backslash,        bar,          bar,    brokenbar ] };

    include "level3(ralt_switch_multikey)"
};

I wanted to have the degree ° symbol on the leftmost key in the number row, which for some reason gets the name tilde or <TLDE>. So, the corresponding line was edited to read

Code:

    key <TLDE> { [     grave,    degree,          bar,          bar ] };

and I was done.  The edited file has a new name, and is called from the xorg.conf instead of the standard "gb" file.
I'm not very good at finding the right and up-to-date docu, so don' ask how long I spend on this 

Hope it'll be of use to somebody.
°Klaus

[tony.]

I think alarm cable would be a good cable to use.

4,6,8,12 core available.

very flexible multistranded conductor.
max 50 volts and 1Amp.

ie

http://www.tlc-direct.co.uk/Products/CALV4.html

regards

tony

[wyleu]

My old laptop is slowly giving up it's ghost, and after lots of faffing about I got myself a new Acer Travelmate Timeline notebook. I don't know what these designers think about, but they forgot to put a degree (°) sign on the keyboard.  

You will smart for that right now       ...
Isn't character mapping fun?

 שלום

[KLD]

Oh look!

Klaus

[wyleu]

I'm trying to get my head round unicode, and given my lazy desire to follow all threads I can find, this is a long process.
Thanks for dredging up that arcane little file. It makes following the chain of events, so much easier, when you get close to the source of the stream. Especially if that outpouring is a little turbulent. 

Unicode itself is an easily grasped concept, but it does lack upside down numbers and emoticons ,
 it's the implementation thats the problem.
I've been trying to build a fairly complete test case but am wondering how far to extend.

° obviously.
and €, but pragmatically what else?...

[KLD]

In my lazy searches I found somebody looking for a key symbol in unicode. There is a challenge! And as additional motivation (as if you need that  ) they wanted to use the key symbol somewhere with SQL, as an indicator for the primary key.

 
Klaus

[wookey]

Unix/Linux use Unicode,
Ubuntu uses UTF

It's a lot more complicated than that actually, but setting everything to 'UTF-8' if you get asked is generally the right answer these days.

Unix/Linux of course uses whatever you tell it to use. And the full path from keyboard mapping through console and desktop character set/fonts to the glyphs that appear on your screen is a vilely complicated thing that you really don't want to know about if you can help it.
You can tell your system to work in english-UTF8 or english-iso8859-1 ('ascii with most western european accents/chars), english-iso-8859-15 (8859-1 plus the euro symbol), plain ascii, any other language you care to name and either UTF-8 or whatever the suitable local charset is (KOI8-R for russian, 8859-various for europe, EUC-JP for japan). Look in /etc/locale.gen (on debian at least) for the full list.

One thing that is worth noting is that 'Unicode' is the full 4-byte character set. But you really don't want to use 4 bytes for every character when almost all the ones you actually use can be represented in one, so files are actually encoded in a devious scheme. Unix/Linux/nearly everything uses UTF-8 for this encoding, which means that characters take up 1, 2, 3 or 4 bytes as required, and files with no funny chars in look exactly the same as old ASCII files. Windows (and Java) uses UTF-16 which means that everything takes up 2 bytes except for some that use 4.

None of this covers font selection, and which fonts cover which parts of the Unicode charset but like I say, you really don't want to know about that - it's not pretty.

Klaus - I find that degree ° is already on my gb keyboard on altgr-shift-0 (and also altgr-shift-leftbracket,leftbracket). (note that that's algr before shift, not shift first - because 'altgr' is the 'compose' key). It comes from the /usr/share/X11/xkb/symbols/latin upon which the /usr/share/X11/xkb/symbols/gb file is based. I see that having it on the top-left key is where a german keyboard user expects to find it :-)

Back to the original subject. Tony - I looked at alarm cable and I'm sure it does generally work OK, but it is normally shielded and the 1-wire spec recommends using unshielded cable because shielded cable increases the capacitance. I have no idea how much it matters in practice. There is clearly something to be said for the fact that it is flexible and you can use 4 cores instead of 8 for "1-wire"!

You can of course get multistranded cat-5 too for a small premium over the single-core stuff (£55 vs £47 for 100m). Personally this is now my favoured cable, just because I can decide later whether to use it for ethernet or 1-wire. And the flex version is more reliable at connectors.

[tony.]

wookey,

standard intruder alarm cable is not shielded its just covered with a pvc oversheath.

you can buy shielded stuff but cant think why you would need to, clearly it will have an application in a commercial/industrial scenario, such as card readers,proximity tags perhaps

tony

[wookey]

Hmm, OK. The CPC catalogue definately gave me the impression that 4-core alarm cable was shielded, but I see from looking again that I was mistaken and it doesn't have to be. It'd be interesting to see whether UTP was better for rejecting mains/other interference when run in skirtings and the like than plain alarm cable. It does certainly look like a good option (along with telephone cable - also 4-core and available stranded as well as solid, and a rather neat flat format).

[wyleu]

For what it's worth I'm playing with a high current +12V & 0V with an additional pair OV & DQ for one wire controlled 'emergency lighting' Basically it's motion sensors talking to one-wire and one wire controlling one-wire controlled LED's. The half bee modules suit all this rather well.

Anyone seen a cable that might suit? 6mm² or even 10mm² (that's Ctrl/shift U00B2 for the ²)  It sounds automobile related and I'm keen to see what might develop at 42Volts in the next few years.

[tony.]

wyleu,

what about a 4 core yy cable, grey in colour, multistrand conductors, so small tight bendi radius etc.

available in large drums

tony

[KLD]

Wyleu
Sounds a bit like a waste of resources to run 1-wire signals in a 6mm² wire, just to keep the installation tidy.  instead of running a 2-core 6mm² alongside your pick of a 1-wire cable.

(After Wookey pointed it out, there are ever so many symbols hidden behind your keys  Try AltGr 2 for the ², or  ³ instead of 
Not sure it's implemented on the karma buttons?

Klaus™

[wyleu]

Klaus™

Very fetching.

Now it's a matter of remembering the short cut ones, Since in one day I'm on Mac, Linux and PC I'll probably just try to learn the grips for Unicode on each respective machine, and then learn the codes . I'm probably looking at making up a 'wyleu standard' crib sheet for that, and If I can use it for unit testing as well then so much the better.

Sorry I didn't make myself clear.

2 high current cores and a twisted pair for one wire data. I can probably make it up with Red/Black wires and either a black/green twist or green-green/white or green-blue     The last pair is the same as the hobbyboard one-wire spec.Although black/white with white as data could be easily achieved.  Pt a bit of  heat wrap over it every .25 metres and i might look quite fetching and allow some form of standard tapping mechanism. Maybe something like the vampire tap from very old Ethernet days.

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0381315

with

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0822888

Athough something like this could be vaguely interesting...

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&binCount=1&Ne=4294957561&Ntt=twisted+pairs&Ntk=I18NAll&Nr=AND%28avl%3auk%2csearchDiscon_uk%3aN%29&Ntx=mode%2bmatchallpartial&N=4294954844&Nty=1