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On 10/12/2025 10:53, c186282 wrote:
> On 12/10/25 05:24, The Natural Philosopher wrote:
>> On 10/12/2025 10:02, c186282 wrote:
>>> On 12/10/25 04:14, Andy Burns wrote:
>>>> c186282 wrote:
>>>>
>>>>> ÿÿ I think it was you ... said how a cam would
>>>>> ÿÿ more or less drop out when the Big Red Truck
>>>>> ÿÿ was there.
>>>> No, maybe TNP said his oil level monitor would drop out?
>>>
>>> ÿÿ Posting traffic has considerably increased of late,
>>> ÿÿ partly my "fault" ... but COSLM was kind of dying
>>> ÿÿ and that would have been tragic. Forgive the sort
>>> ÿÿ of off-topic stuff, but it DOES keep minds alive -
>>> ÿÿ you can't ALWAYS think about Linux without kind
>>> ÿÿ of seizing up :-)
>>>
>> I stated for te record and for the interest of others doing outside 
>> wifi coupled IOT shit that rain wind and possibly cars made a difference.
>>
>> Someone else remarked that so did fire trucks.
>>
>> The downside of the new oil monitor is that is is so accurate - to 
>> within a litre it seems - that I can visibly see how much a shower or 
>> washing the dishes costs me, and a cold night is very expensive. :-)
>> LOL.
>>
>> Now off to write the software that will look at it for me and warn me 
>> of things by email.
>> So I can get on with the next project.
> 
>  ÿ Somebody said something interesting ... that
>  ÿ the effect of the Big Red Truck on the wifi
>  ÿ signal kind of turned it into a radio proximity
>  ÿ sensor. Ya know, THAT might be useful ......
> 
That was in fact how Radar was born. Engineers noted that HF radio was 
affected by planes flying overhead.

Chain Home was built to run between 20MHz and 55MHz.

The Germans sent a Zeppelin to investigate,m but they spotted it miles 
away and switched it off.

Germany thought the frequency was too low for proper radiolocation. 
They thought it was probably a LORAN style system for navigation.

At that time I don't think a radio valve (tube) was much uses over about 
150MHz. They had to sue klystrons and later magnetrons for transmitting 
GigaHertz stuff.


>  ÿ As for The Project ... with enough interesting
>  ÿ input The Project might change ... to something
>  ÿ More Interestingÿ :-)
> 
>  ÿ Hmmm ... My stuff gives off wifi, and there are a
>  ÿ few neighbors too. MIGHT be I could sample signal
>  ÿ strength and come up with certain 'fingerprints' -
>  ÿ like of vehicles driving by or, more important,
>  ÿ the Amazon truck pulling into my driveway ...
>  ÿ BEEP !!!
> 
It is certainly doable at 2.4 GHz.

Build a directional mirror - parabolic, and send a wifi signal up it.

Point it away from a similarly equipped receiver, and wait for something 
to reflect it back.

Or just spend $2 for one already built ready to hook up to your Pi.

https://thepihut.com/products/microwave-motion-sensor-rcwl-0516

>  ÿ See how little stuff can spawn bigger ideas ?ÿ :-)
> 
> 

-- 
"Women actually are capable of being far more than the feminists will 
let them."




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