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???
08/05/05 18:35
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 		 #98906 - and...
Responding to: ???'s previous message
Kai Klaas said:

The only you have to do now, is to find a suited LDR, which provides a resistance change that matches to your micro. In our example an intensity between "daylight" and "dark" should result in 1.5V port voltage, with the weak internal active pull-up (200µA) turned-on.


...and the tolerance on LDRs is usually terrible....Which is why twilight switches have moved to Photodiodes (so I am told)

Steve



List of 33 messages in thread
TopicAuthorDate
Detecting Light with 8051            01/01/70 00:00      
   detecting light            01/01/70 00:00      
      Too specific            01/01/70 00:00      
   have a peek            01/01/70 00:00      
   TAOS inc            01/01/70 00:00      
      simple and cheap            01/01/70 00:00      
         Twilight Switch?            01/01/70 00:00      
         possible schematic            01/01/70 00:00      
            Add            01/01/70 00:00      
               re:add            01/01/70 00:00      
                  NO !            01/01/70 00:00      
                     updated schematic            01/01/70 00:00      
            possible, but not goog            01/01/70 00:00      
               Consensus!            01/01/70 00:00      
                  a comparator with hysteresis constitutes            01/01/70 00:00      
                     Better with            01/01/70 00:00      
                        a 555 ....            01/01/70 00:00      
                           555...            01/01/70 00:00      
         The simplest solution would be...            01/01/70 00:00      
            and...            01/01/70 00:00      
   Try this, It works and it's cheap            01/01/70 00:00      
      how do you know?            01/01/70 00:00      
         OT - you are fully right erik            01/01/70 00:00      
            that is not the issue            01/01/70 00:00      
               What is diddelysquat            01/01/70 00:00      
                  http://wordwebonline.com/en/DIDDLYSQUAT            01/01/70 00:00      
         Because I build it            01/01/70 00:00      
            nobody disputes that, but that does not            01/01/70 00:00      
            re:you built it            01/01/70 00:00      
               and thus Kai states "it's not clear, wh            01/01/70 00:00      
                  re:            01/01/70 00:00      
                     Yes-ish            01/01/70 00:00      
                     Isn't it funny...            01/01/70 00:00      

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