Colony

  Authors: James Kong and Greg Tress

  Last Modified: 4/30/06 by James

  -Started log_distance conversion function !!!NOT COMPLETE!!!

  -Cleaning up comments

  -----------------

  rangefinder.c

  Using Sharp GP2D02 IR Rangefinder

  Vin is the input to the rangefinder, designated RANGE_CTRL.

  Vout is the output from the rangefinder, designated RANGE_IN# where # is the rangefinder you are reading from

  Expected Initial Conditions:

  Vin is high and Vout should read high.

  Usage:

  1.) Set Vin low. Vout should read low.

  2.) Wait for high on Vout.

  3.) Begin clocking Vin and reading 8 bits from Vout (MSB first).

  4.) Set Vin high for 2ms or more to turn off rangefinder

  read_distance returns the 8-bit reading from the rangefinder

  parameters:

  range_id - dio pin set as the rangefinder Vout [i.e. RANGE_IN0]

  NOTE:

  The Sharp GD2D02 returns values on a decreasing logrithmic scale.

  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.

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

   I'm using this for the heck of it.  We can do whatever.

   Note the minimum value is .4V (20), and the maximum is 2.6V (133).

   Gives distance in mm.

   excel formula(valid for inputs 20-133):  ROUND(2353.6*(E2^(-1.1146))*10,0)

   This is only valid for the GP2D12, with objects directly ahead and more than

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

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

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

  ,288,282,276,270,265,260,255,250,245,241,237,232,228,224,221,217

  ,213,210,207,203,200,197,194,191,189,186,183,181,178,176,173,171

  ,169,166,164,162,160,158,156,154,152,151,149,147,145,144,142,140

  ,139,137,136,134,133,131,130,129,127,126,125,124,122,121,120,119

  ,118,117,115,114,113,112,111,110,109,108,107,106,105,105,104,103

  ,102,101

  digital_output(_PIN_B4,0);

int range_read_distance (int range_id) {

  return linearize_distance(analog8(range_id));

int linearize_distance(int value) {

  if(value < MIN_IR_ADC8) {

  } else if(value > MAX_IR_ADC8) {

  } else {