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Revision 1372

Added by Abraham Levkoy over 13 years ago

Moved prototype for linearize_distance and constants MIN_IR_ADC8 and
MAX_IR_ADC8 from rangefinder.c to rangefinder.h. Added Doxy comments for these
items. Realize that linearize_distance was probably intended to be hidden from
the average user, but doxy errors compelled me to act.

View differences:

rangefinder.c
68 68 

  		




  69
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  NOTE:


  		




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  The Sharp GD2D02 returns values on a decreasing logrithmic scale.


  		




  71
  
  
    
  So higher values correspond to closer distances.  Use linearize_distance to convert to normal centimeter scale.  Also, when reading distances closer than 8cm, the Sharp GD2D02 will return lower values than the values at 8cm.


  		




  
  71
  
    
  So higher values correspond to closer distances.  Use linearize_distance to convert to normal centimeter scale.


  		




  
  72
  
    
  Also, when reading distances closer than 8cm, the Sharp GD2D02 will return lower values than the values at 8cm.


  		




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  At this point, we are only reading from one rangefinder [RANGE_IN0].


  		




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*/


  		




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  ......




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   10cm from the detector.  See the datasheet for more information.


  		




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*/


  		




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#define MIN_IR_ADC8 20


  		




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#define MAX_IR_ADC8 133


  		




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static int IR_dist_conversion[114] = {


  		




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  800,791,751,714,681,651,623,597,574,552,531,512,494,478,462,447


  		




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  ,434,421,408,397,386,375,365,356,347,338,330,322,315,307,301,294


  		




  ......




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  ,102,101


  		




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};


  		




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int linearize_distance(int value);


  		




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/**


  		




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 * @defgroup rangefinder Rangefinder


  		




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 * @brief Functions for using the IR rangefinders


  		




  ......




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 *


  		




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 * @see range_init


  		




  134
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 **/


  		




  135
  
  
    
int range_read_distance (int range_id) {


  		




  
  131
  
    
int range_read_distance(int range_id) {


  		




  136
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  return linearize_distance(analog8(range_id));


  		




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}


  		




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/** @} **/ //end defgroup


  		




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/**


  		




  
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 * Transforms distance readings from logarithmic to linear scale.


  		




  
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 * This probably isn't the function you are looking for.


  		




  
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 *


  		




  
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 * @param value the 8-bit analog value from rangefinder


  		




  
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 *


  		




  
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 * @return linearized distance reading from rangefinder (integer in [101,800])


  		




  
  142
  
    
 **/


  		




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int linearize_distance(int value) {


  		




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  if(value < MIN_IR_ADC8) {


  		




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    return -1;


  		




  ......




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    return IR_dist_conversion[value - MIN_IR_ADC8];


  		




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  }


  		




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}


  		




  
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/** @} **/ //end defgroup


  		












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