I'm using these below for detecting outdoor cat. Transmitter works at
50ft, but maybe not 50M. The 9V batt lasts for nearly a year. It's
thermal-IR, but if non-ambient mail is falling right across it, probably
it will trigger. Or, cut into the sensor and add a leaf-switch and
resistor.
In reply to MSF's message of Thu, 30 Dec 2021 00:32:28 +:
Hi,
[snip]
>
>On the other hand, you could go totally old school and use a coherer. The mail
>deliverer might object to the long antenna on the mail box, but it could work.
>Check out my favorite coherer link:
>
On the other hand, you could go totally old school and use a coherer. The mail
deliverer might object to the long antenna on the mail box, but it could work.
Check out my favorite coherer link:
http://sparkbangbuzz.com/els/coherer-el.htm
‐‐‐ Original Message ‐‐‐
On Wednesday,
Very sad for the condition of the almost non-existent manufacturing sector of
the U.S. economy. I'm in a manufacturing business and almost all of my
suppliers are foreign. I've been ranting on for nearly 40 years about us giving
away the store on manufacturing and have been mocked for it. The
Brilliant ... and (in general) such gadgets as solar powered motion detectors
are such a bargain aren't they?
Isn't it amazing how the level of affordable sophistication in relatively
mundane products has increased - and at very low cost considering the
technology involved. The progress in
The solution to your problem has likely already been built. It's the remote
motion detector. You can buy these on ebay for around 20 dollars US. Just drop
the motion detector in the mailbox and it triggers a really loud alarm on the
receiving unit inside your house. I have used these in my back
In reply to MSF's message of Wed, 29 Dec 2021 18:29:56 +:
Hi,
[snip]
>
>What's your goal? Is it to demonstrate how simple or clever such a thing could
>be or do you have a practical result in mind? Do you want this to operate as a
>remote switch or merely to show a record of the bit
In reply to Terry Blanton's message of Wed, 29 Dec 2021 11:57:08 -0500:
Hi,
[snip]
>https://kotsanas.com/gb/exh.php?exhibit=1201001
>
>:)
This sounds like the origin of the concept behind Morse code/EBCDIC/ASCII.
Regards,
Robin van Spaandonk
What's your goal? Is it to demonstrate how simple or clever such a thing could
be or do you have a practical result in mind? Do you want this to operate as a
remote switch or merely to show a record of the bit transfer on the receiving
end?
‐‐‐ Original Message ‐‐‐
On Wednesday,
https://kotsanas.com/gb/exh.php?exhibit=1201001
:)
Sound is still more reliable, easy to produce and receive, cheaper
electronics involved and can carry more info if needed. You also don't need
to focus it. Why not to go with this solution?
On Tue, Dec 28, 2021 at 7:24 PM Robin
wrote:
> In reply to Jones Beene's message of Wed, 29 Dec 2021
In reply to Jones Beene's message of Wed, 29 Dec 2021 02:16:22 + (UTC):
Hi,
[snip]
> Here's one to look at
>https://en.wikipedia.org/wiki/Optical_telegraph
>
Actually I considered a mirror system, but it wouldn't work on cloudy days.
Regards,
Robin van Spaandonk
In reply to Giovanni Santostasi's message of Tue, 28 Dec 2021 17:58:27 -0800:
Hi,
[snip]
>Anyway, probably sound is the best and cheapest mean to transfer the info
>on such a short distance (is the distance an open space or are there
>buildings?).
Open space.
>It would be easy to create a
In reply to Giovanni Santostasi's message of Tue, 28 Dec 2021 17:51:41 -0800:
Hi,
[snip]
>What is the rate of transfer of information? Only a single bit one time?
No more than 1 bit / day.
Regards,
Robin van Spaandonk
Here's one to look at
https://en.wikipedia.org/wiki/Optical_telegraph
Giovanni Santostasi wrote:
What is the rate of transfer of information? Only a single bit one time?
On Tue, Dec 28, 2021 at 5:43 PM Robin wrote:
In reply to Giovanni Santostasi's message of Tue, 28 Dec 2021
Anyway, probably sound is the best and cheapest mean to transfer the info
on such a short distance (is the distance an open space or are there
buildings?). It would be easy to create a device that can separate sound
based on frequency or loudness (Arduino hooked to a microphone). If it is
only a
What is the rate of transfer of information? Only a single bit one time?
On Tue, Dec 28, 2021 at 5:43 PM Robin
wrote:
> In reply to Giovanni Santostasi's message of Tue, 28 Dec 2021 17:35:35
> -0800:
> Hi,
>
> Very inventive. :) However no human intervention possible. Method
> preferably
In reply to Giovanni Santostasi's message of Tue, 28 Dec 2021 17:35:35 -0800:
Hi,
Very inventive. :) However no human intervention possible. Method preferably
electronic.
>An arrow with a message written on a piece of paper wrapped around the
>arrow. 50 meters should be a relatively easy shot.
An arrow with a message written on a piece of paper wrapped around the
arrow. 50 meters should be a relatively easy shot.
Giovanni
On Tue, Dec 28, 2021 at 5:23 PM Robin
wrote:
> In reply to Robin's message of Wed, 29 Dec 2021 12:21:14 +1100:
> Hi,
>
> I should add that the transmitter has no
In reply to Robin's message of Wed, 29 Dec 2021 12:21:14 +1100:
Hi,
I should add that the transmitter has no mains connection thus may at best be
battery powered.
Regards,
Robin van Spaandonk
Hi,
I'm looking for an elegant, simple, cheap means of transmitting a single bit of
information over a distance of 50
meters, without wires.
Imaginative solutions sought. :)
Regards,
Robin van Spaandonk
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