MAXREFDES117# Code Documentation  V01.00
Heart Rate / SpO2 Monitor
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algorithm.h
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62 #ifndef ALGORITHM_H_
63 #define ALGORITHM_H_
64 #include <arduino.h>
65 
66 #define true 1
67 #define false 0
68 #define FS 25 //sampling frequency
69 #define BUFFER_SIZE (FS* 4)
70 #define MA4_SIZE 4 // DONOT CHANGE
71 #define min(x,y) ((x) < (y) ? (x) : (y))
72 
73 //uch_spo2_table is approximated as -45.060*ratioAverage* ratioAverage + 30.354 *ratioAverage + 94.845 ;
74 const uint8_t uch_spo2_table[184]={ 95, 95, 95, 96, 96, 96, 97, 97, 97, 97, 97, 98, 98, 98, 98, 98, 99, 99, 99, 99,
75  99, 99, 99, 99, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100,
76  100, 100, 100, 100, 99, 99, 99, 99, 99, 99, 99, 99, 98, 98, 98, 98, 98, 98, 97, 97,
77  97, 97, 96, 96, 96, 96, 95, 95, 95, 94, 94, 94, 93, 93, 93, 92, 92, 92, 91, 91,
78  90, 90, 89, 89, 89, 88, 88, 87, 87, 86, 86, 85, 85, 84, 84, 83, 82, 82, 81, 81,
79  80, 80, 79, 78, 78, 77, 76, 76, 75, 74, 74, 73, 72, 72, 71, 70, 69, 69, 68, 67,
80  66, 66, 65, 64, 63, 62, 62, 61, 60, 59, 58, 57, 56, 56, 55, 54, 53, 52, 51, 50,
81  49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 31, 30, 29,
82  28, 27, 26, 25, 23, 22, 21, 20, 19, 17, 16, 15, 14, 12, 11, 10, 9, 7, 6, 5,
83  3, 2, 1 } ;
84 static int32_t an_x[ BUFFER_SIZE]; //ir
85 static int32_t an_y[ BUFFER_SIZE]; //red
86 
87 
88 #if defined(ARDUINO_AVR_UNO)
89 //Arduino Uno doesn't have enough SRAM to store 100 samples of IR led data and red led data in 32-bit format
90 //To solve this problem, 16-bit MSB of the sampled data will be truncated. Samples become 16-bit data.
91 void maxim_heart_rate_and_oxygen_saturation(uint16_t *pun_ir_buffer, int32_t n_ir_buffer_length, uint16_t *pun_red_buffer, int32_t *pn_spo2, int8_t *pch_spo2_valid, int32_t *pn_heart_rate, int8_t *pch_hr_valid);
92 #else
93 void maxim_heart_rate_and_oxygen_saturation(uint32_t *pun_ir_buffer, int32_t n_ir_buffer_length, uint32_t *pun_red_buffer, int32_t *pn_spo2, int8_t *pch_spo2_valid, int32_t *pn_heart_rate, int8_t *pch_hr_valid);
94 #endif
95 void maxim_find_peaks(int32_t *pn_locs, int32_t *n_npks, int32_t *pn_x, int32_t n_size, int32_t n_min_height, int32_t n_min_distance, int32_t n_max_num);
96 void maxim_peaks_above_min_height(int32_t *pn_locs, int32_t *n_npks, int32_t *pn_x, int32_t n_size, int32_t n_min_height);
97 void maxim_remove_close_peaks(int32_t *pn_locs, int32_t *pn_npks, int32_t *pn_x, int32_t n_min_distance);
98 void maxim_sort_ascend(int32_t *pn_x, int32_t n_size);
99 void maxim_sort_indices_descend(int32_t *pn_x, int32_t *pn_indx, int32_t n_size);
100 
101 #endif /* ALGORITHM_H_ */
102