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   REPLYADDR tnp@invalid.invalid   
   REPLYTO 3:770/3.0 UUCP   
   MSGID:  800d7b90   
   REPLY:  a44348bb   
   PID: SoupGate-Win32 v1.05   
   On 30/03/2024 16:26, Pancho wrote:   
   > On 30/03/2024 09:17, The Natural Philosopher wrote:   
   >> On 30/03/2024 02:04, Jim H wrote:   
   >>> On Fri, 29 Mar 2024 10:49:13 +0000, in ,   
   >>> The Natural Philosopher  wrote:   
   >>>   
   >>>> Maybe ascii art will help   
   >>>>   
   >>>> CONTROL=10µs   
   >>>> ____| |________   
   >>>>   
   >>>> RETURN = wahatever   
   >>>> _____|^^^^^^^^^^^^|____________   
   >>>>   
   >>>   
   >>> Assuming my bleary-eyed math is correct, 10µs is the length of one   
   >>> cycle of ultrasound at 100,000 Hz.   
   >>>   
   >> The width of that pulse is pretty much immaterial - its only a digital   
   >> trigger, It doesn't send anything directly.   
   >>   
   >> The unit does that, and senses a high to the output. Then it transmits   
   >> a squawk., When it receives an echo it switches that to low.   
   >>   
   >> Its a smart device .   
   >>   
   >   
   > I think that is the part I was missing. I assumed it was like an analog   
   > device, out pin was for send  and the in pin signalled it was receiving.   
   >   
   > On reflection, the code makes sense if it is a smart device. The in pin   
   > just goes high (or low) for the period between sending and receiving a   
   > few micro seconds of the echo.   
   >   
   >   
   >> https://cdn.sparkfun.com/datasheets/Sensors/Proximity/HCSR04.pdf   
   >>   
   >   
   > Not the most precise wording.   
   >   
   > Having taken the trouble to understand. I might buy one to tell me if my   
   > garage door is open. Buy an echo device that is, not a PICO.   
   >   
   >   
   Well hook it to a pico and tell a server via wifi that  the door   
   is/isn't open!   
      
   It seems reiable so far.   
      
      
   Now running of 3 dry cells to see at what point the voltage gets too low   
   for reliable pinging.   
      
      
   --   
   Canada is all right really, though not for the whole weekend.   
      
   "Saki"   
      
   --- SoupGate-Win32 v1.05   
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