randomnes...

I just installed some smoke detectors. They're wireless
interconnected, and have 8 dip switches to set their interconnect
code. I went to random.org to generate a random 8 bit number, which
it will handily show you in binary. It generated 10000000. While I'm
sure that's random, it doesn't seem like a good choice, so I generated
another one: 00000001. the third was suitable.

--
sig 78

On Sun, 3 Jul 2016 15:12:21 +0000 (UTC), David Scheidt
wrote:

I just installed some smoke detectors. They're wireless
interconnected, and have 8 dip switches to set their interconnect
code. I went to random.org to generate a random 8 bit number, which
it will handily show you in binary. It generated 10000000. While I'm
sure that's random, it doesn't seem like a good choice, so I generated
another one: 00000001. the third was suitable.

Are you really sure that they're random? Seems like an odd
coincidence.

Sounds like a Kidde smoke detector. If you had bought a First Alert
OneLink, it has 65,000 possible codes automagically set (no dip
switches). Kidde use 433.925MHz which is also shared by everything
from home weather stations to car alarm key fobs. 8 switches only
gives you 256 available codes. If you live in a large apartment
building, with a high probability of similar devices, duplicate codes
are possible. I suggest you pick a pattern of switches which is
random, rather than obvious patterns such as all 0, all 1, every other
switch 0 or 1, or other such patterns.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote:
:On Sun, 3 Jul 2016 15:12:21 +0000 (UTC), David Scheidt
wrote:

:I just installed some smoke detectors. They're wireless
:interconnected, and have 8 dip switches to set their interconnect
:code. I went to random.org to generate a random 8 bit number, which
:it will handily show you in binary. It generated 10000000. While I'm
:sure that's random, it doesn't seem like a good choice, so I generated
:another one: 00000001. the third was suitable.

:Are you really sure that they're random? Seems like an odd
:coincidence.

****, why did I post this here? Bah.

Yeah, random.org uses physical random number generators, so they
should be random. There's a bigger chance o this sort of thing than
you might think, though, since there are a number of sequences that
would make me pick a new number.

:Sounds like a Kidde smoke detector. If you had bought a First Alert
:OneLink, it has 65,000 possible codes automagically set (no dip
:switches). Kidde use 433.925MHz which is also shared by everything
:from home weather stations to car alarm key fobs. 8 switches only
:gives you 256 available codes. If you live in a large apartment
:building, with a high probability of similar devices, duplicate codes
:are possible. I suggest you pick a pattern of switches which is
:random, rather than obvious patterns such as all 0, all 1, every other
:switch 0 or 1, or other such patterns.

It's a kidde. I'm in a single family house, dense on the ground. Not
two worried about interference.


--
sig 102

with David Scheidt wrote:

I just installed some smoke detectors. They're wireless
interconnected, and have 8 dip switches to set their interconnect
code. I went to random.org to generate a random 8 bit number, which
it will handily show you in binary.

You could just ask:

{2929:8} [0:0]% perl -wle 'printf "%08b\n", rand 256 foreach 0 .. 7'
11100010
01010011
01101101
00000100
00011110
01010110
10110100
01001111

It generated 10000000. While I'm sure that's random, it doesn't seem
like a good choice, so I generated another one: 00000001. the third
was suitable.

You just defeated randomness. However, it's possible that random.org is
a crap. See above.

--
Torvalds' goal for Linux is very simple: World Domination
Stallman's goal for GNU is even simpler: Freedom

Eric Pozharski wrote:
:with David Scheidt wrote:

: I just installed some smoke detectors. They're wireless
: interconnected, and have 8 dip switches to set their interconnect
: code. I went to random.org to generate a random 8 bit number, which
: it will handily show you in binary.

:You could just ask:

: {2929:8} [0:0]% perl -wle 'printf "%08b\n", rand 256 foreach 0 .. 7'
: 11100010
: 01010011
: 01101101
: 00000100
: 00011110
: 01010110
: 10110100
: 01001111

: It generated 10000000. While I'm sure that's random, it doesn't seem
: like a good choice, so I generated another one: 00000001. the third
: was suitable.

:You just defeated randomness. However, it's possible that random.org is
:a crap. See above.

My goal isn't randomness, though. It's local uniqueness. Removing
the numbers likely to be used by people not selecting randomly, and
then selecting randomly from that set is better than just randomly
selecting from the whole set. See, for instance, a table of EV of
numbers in shared jackpot lottery. Numbers that can't be constructed
as dates have a higher EV than those that can, even though they're no
ore likely to be selected.

--
sig 33

On Sunday, July 3, 2016 at 11:12:23 AM UTC-4, David Scheidt wrote:
I just installed some smoke detectors. They're wireless
interconnected, and have 8 dip switches to set their interconnect
code. I went to random.org to generate a random 8 bit number, which
it will handily show you in binary. It generated 10000000. While I'm
sure that's random, it doesn't seem like a good choice, so I generated
another one: 00000001. the third was suitable.

--
sig 78

A HOBBY GENERATING RANDOM NUMBERS ?

as Pi or Integers ?

is there a category name ?

https://www.google.com/#q=RANDOM+NUMBER+GENERATORS


whheeeeeeee....the thrill of victory agony of dah feet .......eureka !

sez there...MATH EPIPHANY

a new hobby for Contador ?

On Sunday, July 3, 2016 at 11:12:23 AM UTC-4, David Scheidt wrote:
I just installed some smoke detectors. They're wireless
interconnected, and have 8 dip switches to set their interconnect
code. I went to random.org to generate a random 8 bit number, which
it will handily show you in binary. It generated 10000000. While I'm
sure that's random, it doesn't seem like a good choice, so I generated
another one: 00000001. the third was suitable.

--
sig 78

https://groups.google.com/forum/#!fo...tronics.repair

On 04/07/2016 9:26 AM, David Scheidt wrote:
Eric Pozharski wrote:
:with David Scheidt wrote:

: I just installed some smoke detectors. They're wireless
: interconnected, and have 8 dip switches to set their interconnect
: code. I went to random.org to generate a random 8 bit number, which
: it will handily show you in binary.

:You could just ask:

: {2929:8} [0:0]% perl -wle 'printf "%08b\n", rand 256 foreach 0 .. 7'
: 11100010
: 01010011
: 01101101
: 00000100
: 00011110
: 01010110
: 10110100
: 01001111

: It generated 10000000. While I'm sure that's random, it doesn't seem
: like a good choice, so I generated another one: 00000001. the third
: was suitable.

:You just defeated randomness. However, it's possible that random.org is
:a crap. See above.

My goal isn't randomness, though. It's local uniqueness. Removing
the numbers likely to be used by people not selecting randomly, and
then selecting randomly from that set is better than just randomly
selecting from the whole set. See, for instance, a table of EV of
numbers in shared jackpot lottery. Numbers that can't be constructed
as dates have a higher EV than those that can, even though they're no
ore likely to be selected.


Yes, but random numbers are random. How do you know they will be
unique? There are only 2^8 choices. Can't you just scan for existing
numbers? Sort of like pinging an IP address before assigning it to a
new PC.

On Sun, 3 Jul 2016 18:22:54 +0000 (UTC), David Scheidt
wrote:

****, why did I post this here? Bah.

I like it. It's an improvement over the usual off topic political
discussions.

It's a kidde. I'm in a single family house, dense on the ground. Not
two worried about interference.

So, what happens when you duplicate the code with one the neighbors?
Push the test button and their smoke alarm is triggered? If so, that
sounds like fun. Try setting one of your alarms at the default code
00000000 and see what happens. If nothing happens, try it again near
a large apartment complex. Extra credit for lashing the smoke alarm
to your bicycle and riding around randomly with it activated.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Monday, July 4, 2016 at 10:39:41 AM UTC-4, Jeff Liebermann wrote:
On Sun, 3 Jul 2016 18:22:54 +0000 (UTC), David Scheidt
wrote:

****, why did I post this here? Bah.

I like it. It's an improvement over the usual off topic political
discussions.

It's a kidde. I'm in a single family house, dense on the ground. Not
two worried about interference.

So, what happens when you duplicate the code with one the neighbors?
Push the test button and their smoke alarm is triggered? If so, that
sounds like fun. Try setting one of your alarms at the default code
00000000 and see what happens. If nothing happens, try it again near
a large apartment complex. Extra credit for lashing the smoke alarm
to your bicycle and riding around randomly with it activated.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

using a new Ford sender (2008) was possible to set off all Fords in the dealers lotand...in the Mall lot