Revision 1372
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.
| trunk/code/projects/libdragonfly/rangefinder.c | ||
|---|---|---|
| 68 | 68 |
|
| 69 | 69 |
NOTE: |
| 70 | 70 |
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. |
|
| 72 | 73 |
At this point, we are only reading from one rangefinder [RANGE_IN0]. |
| 73 | 74 |
*/ |
| 74 | 75 |
|
| ... | ... | |
| 85 | 86 |
10cm from the detector. See the datasheet for more information. |
| 86 | 87 |
*/ |
| 87 | 88 |
|
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#define MIN_IR_ADC8 20 |
|
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#define MAX_IR_ADC8 133 |
|
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|
|
| 91 | 89 |
static int IR_dist_conversion[114] = {
|
| 92 | 90 |
800,791,751,714,681,651,623,597,574,552,531,512,494,478,462,447 |
| 93 | 91 |
,434,421,408,397,386,375,365,356,347,338,330,322,315,307,301,294 |
| ... | ... | |
| 99 | 97 |
,102,101 |
| 100 | 98 |
}; |
| 101 | 99 |
|
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int linearize_distance(int value); |
|
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|
|
| 104 | 100 |
/** |
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* @defgroup rangefinder Rangefinder |
| 106 | 102 |
* @brief Functions for using the IR rangefinders |
| ... | ... | |
| 132 | 128 |
* |
| 133 | 129 |
* @see range_init |
| 134 | 130 |
**/ |
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int range_read_distance (int range_id) {
|
|
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int range_read_distance(int range_id) {
|
|
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return linearize_distance(analog8(range_id)); |
| 137 | 133 |
} |
| 138 | 134 |
|
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/** @} **/ //end defgroup |
|
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|
|
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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]) |
|
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**/ |
|
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int linearize_distance(int value) {
|
| 142 | 144 |
if(value < MIN_IR_ADC8) {
|
| 143 | 145 |
return -1; |
| ... | ... | |
| 147 | 149 |
return IR_dist_conversion[value - MIN_IR_ADC8]; |
| 148 | 150 |
} |
| 149 | 151 |
} |
| 152 |
|
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/** @} **/ //end defgroup |
|
| trunk/code/projects/libdragonfly/rangefinder.h | ||
|---|---|---|
| 52 | 52 |
#define IR4 3 |
| 53 | 53 |
/** @brief IR Rangefinder 5 **/ |
| 54 | 54 |
#define IR5 2 |
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/** @brief smallest meaningful rangefinder reading (logarithmic scale) **/ |
|
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#define MIN_IR_ADC8 20 |
|
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/** @brief largest meaningful rangefinder reading (logarithmic scale) **/ |
|
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#define MAX_IR_ADC8 133 |
|
| 55 | 59 |
|
| 56 | 60 |
/** @brief Initialize the rangefinders **/ |
| 57 | 61 |
void range_init(void); |
| 58 | 62 |
/** @brief Read the distance from a rangefinder **/ |
| 59 | 63 |
int range_read_distance(int range_id); |
| 64 |
/** @brief Convert logarithmic-scale distance readings to a linear scale **/ |
|
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int linearize_distance(int value); |
|
| 60 | 66 |
|
| 61 | 67 |
/** @} **/ //end addtogroup |
| 62 | 68 |
|
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