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???
05/19/08 19:44
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 		 #154918 - Precision...
Responding to: ???'s previous message
Richard Erlacher said:
I don't know what Robert's application for this pot that he's measuring is, nor do I know how precise or accurate his readings must be.


The answer is that the readings don't really have to be that accurate or precise in as much as I don't really care if I'm measuring 2.016V for example. This is a MIDI control for controlling parameters on a synthesizer (for example) and what really matters is that there should be no output unless the control has been moved.

The actual output must vary from 0-127 (the range of a MIDI message) so I'm not all that concerned with resolution either.

What I've done is to implement a set of buffers that check if the value currently being read is the same as one of the last 8 values read. If it is, then don't send the result. This may be crude, but it seems to work quite nicely within my requirements, and has removed the flicker I was experiencing.

Thanks to all who responded.




List of 41 messages in thread
TopicAuthorDate
ADC smoothing assistance...            01/01/70 00:00      
   Low-pass filter            01/01/70 00:00      
      How stabile is your power supply?            01/01/70 00:00      
         Not very, apparently.            01/01/70 00:00      
            Getting better...            01/01/70 00:00      
            To ground            01/01/70 00:00      
            Start by cleaning up the supply ...            01/01/70 00:00      
               Right!            01/01/70 00:00      
            Correction.            01/01/70 00:00      
               Maybe what you need is a low-impedance probe            01/01/70 00:00      
                  Springtime...            01/01/70 00:00      
                     yes, that looks like mine ... sort-of            01/01/70 00:00      
      Still listening...            01/01/70 00:00      
   Digital and Analog            01/01/70 00:00      
   try steady and more than minimum            01/01/70 00:00      
   ahhhhhh...........so its not only me!            01/01/70 00:00      
   is 2 lsb random error close enough?            01/01/70 00:00      
      Thanks...            01/01/70 00:00      
      Yep.....and that IS the final answer......            01/01/70 00:00      
      Don't truncate ...            01/01/70 00:00      
   LSB flickering            01/01/70 00:00      
      Erm ... not quite true.            01/01/70 00:00      
         Specific Case....            01/01/70 00:00      
            Should work in any case ...            01/01/70 00:00      
         Sorry, but you are entirely wrong...            01/01/70 00:00      
            You must know more about the flickering            01/01/70 00:00      
            I shouldn\\\'t post after a long workday ...            01/01/70 00:00      
   I need to chime in on this thread,,,,            01/01/70 00:00      
      throwing away bits            01/01/70 00:00      
      Integrate and Decimate            01/01/70 00:00      
         Here's my code            01/01/70 00:00      
            Where's the integration?            01/01/70 00:00      
         Dropping bits will not prevent flickering...            01/01/70 00:00      
            this confuses the issue            01/01/70 00:00      
               Immanent flickering            01/01/70 00:00      
                  I don't disagree ...            01/01/70 00:00      
                     Precision...            01/01/70 00:00      
   How I solved my Midi Controller LSB Flicker/Flutte            01/01/70 00:00      
      "Slack" same as hystersis            01/01/70 00:00      
         Sorry!            01/01/70 00:00      
      slack            01/01/70 00:00      

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