Diff: pressure_sensors.cpp

Revision:

8:208d965a3bd2

Parent:

7:f4e248182d31

Child:

9:95fdcdc0977e

--- a/pressure_sensors.cpp	Mon Apr 20 21:58:36 2020 +0000
+++ b/pressure_sensors.cpp	Thu Apr 23 17:05:36 2020 +0000
@@ -1,6 +1,7 @@
 
 #include "mbed.h"
 #include "stdint.h"
+#include "math.h"
 #include "project_defines.h"
 #include "pressure_sensors.h"
 
@@ -10,9 +11,11 @@
 I2C pressure_sensor_02(PRESSURE_SENSOR_02_SDA_PIN, PRESSURE_SENSOR_02_SCL_PIN);
 
 /* Global variable definition */
-uint16_t pressure_01_bin, pressure_02_bin, diff_pressure_bin;
-float pressure_01_psi, pressure_02_psi; 
-float diff_pressure_psi;
+int16_t pressure_01_bin, pressure_02_bin;
+float pressure_01_psi, pressure_02_psi;
+float flow_lpm, volume_ml;
+
+//float diff_pressure_psi;
 
 char sensor_read_data_buffer[2];
 
@@ -31,13 +34,47 @@
     pressure_01_bin = ((sensor_read_data_buffer[0] << 8) | sensor_read_data_buffer[1]) & 0x3FFF;
     pressure_sensor_02.read(PRESSURE_SENSOR_02_SRA, sensor_read_data_buffer, 2);
     pressure_02_bin = ((sensor_read_data_buffer[0] << 8) | sensor_read_data_buffer[1]) & 0x3FFF;
-    diff_pressure_bin =  pressure_01_bin - pressure_02_bin;
     
     /* Calculate pressure values in PSI */
     pressure_01_psi = (5.0 * pressure_01_bin) / 16383; 
     pressure_02_psi = (5.0 * pressure_02_bin) / 16383;
-    diff_pressure_psi = (5.0 * diff_pressure_bin) / 16383;
+
     
 } 
 
+void Calculate_Flow_From_Pressure(void){
+    
+    int16_t diff_pressure_bin;
+    float diff_pressure_psi;
+    
+    diff_pressure_bin =  pressure_02_bin - pressure_01_bin;
+    diff_pressure_psi = (5.0 * diff_pressure_bin) / 16383;
+    
+    if(diff_pressure_psi < 0){
+        flow_lpm = -SPIROMETER_SENSOR_CONSTANT * sqrt(-diff_pressure_psi);    
+    }else{
+        flow_lpm = SPIROMETER_SENSOR_CONSTANT * sqrt(diff_pressure_psi);  
+    }    
+}
 
+void Calculate_Volume_From_Flow(void){
+    
+    static float previous_flow_lpm = 0.0;
+    float delta_volume_ml;
+    
+    delta_volume_ml = (PRESSURE_SENSOR_READ_PERIOD_MS * (flow_lpm + previous_flow_lpm)) / 60.0;
+    
+    volume_ml = volume_ml + delta_volume_ml;
+    
+    previous_flow_lpm = flow_lpm;
+    
+}
+
+void Pressure_01_LPF(void){
+
+}
+
+
+void Pressure_02_LPF(void){
+
+}