From: Sam Moore <matches@ucc.asn.au>
Date: Mon, 14 Oct 2013 06:28:21 +0000 (+0800)
Subject: Add pressure sensors
X-Git-Url: https://git.ucc.asn.au/?a=commitdiff_plain;h=a87a6176816d9dc67e0cee99e707a5e87c3a7c4d;p=matches%2FMCTX3420.git

Add pressure sensors

Untested on BBB
---

diff --git a/server/bbb_pin_defines.h b/server/bbb_pin_defines.h
index 2eb2d08..cb77dac 100644
--- a/server/bbb_pin_defines.h
+++ b/server/bbb_pin_defines.h
@@ -136,6 +136,9 @@ extern const unsigned char g_pin_index_to_gpio[GPIO_NUM_PINS];
 #define ADC5 5
 #define ADC6 6
 #define ADC7 7
+#define ADC_VOLTAGE_MAX 1800
+#define ADC_RAW_MAX (2 << ADC_BITS)
+#define ADC_TO_MVOLTS(x) ((double)((x)/2 << ADC_BITS) * (double)ADC_VOLTAGE_MAX)
 
 /** Number of ADC pins **/
 #define ADC_NUM_PINS 8
diff --git a/server/sensor.c b/server/sensor.c
index 792bbbd..fd477c9 100644
--- a/server/sensor.c
+++ b/server/sensor.c
@@ -68,11 +68,14 @@ int Sensor_Add(const char * name, int user_id, ReadFn read, InitFn init, CleanFn
  */
 #include "sensors/resource.h"
 #include "sensors/strain.h"
-#include "sensors/piped.h"
+#include "sensors/pressure.h"
 void Sensor_Init()
 {
 	Sensor_Add("cpu_stime", RESOURCE_CPU_SYS, Resource_Read, NULL, NULL, 1e50,-1e50,1e50,-1e50);	
 	Sensor_Add("cpu_utime", RESOURCE_CPU_USER, Resource_Read, NULL, NULL, 1e50,-1e50,1e50,-1e50);	
+	Sensor_Add("pressure_high0", PRES_HIGH0, Pressure_Read, Pressure_Init, Pressure_Cleanup, 800, 110, 800, 110);
+	Sensor_Add("pressure_high1", PRES_HIGH1, Pressure_Read, Pressure_Init, Pressure_Cleanup, 800, 110, 800, 110);
+	Sensor_Add("pressure_low0", PRES_LOW0, Pressure_Read, Pressure_Init, Pressure_Cleanup, 250, 110, 250, 110);
 	//Sensor_Add("../testing/count.py", 0, Piped_Read, Piped_Init, Piped_Cleanup, 1e50,-1e50,1e50,-1e50);
 	//Sensor_Add("strain0", STRAIN0, Strain_Read, Strain_Init, 5000,0,5000,0);
 	//Sensor_Add("strain1", STRAIN1, Strain_Read, Strain_Init, 5000,0,5000,0);
diff --git a/server/sensors/Makefile b/server/sensors/Makefile
index b72201d..a412f7c 100644
--- a/server/sensors/Makefile
+++ b/server/sensors/Makefile
@@ -3,7 +3,7 @@ CXX = gcc
 FLAGS = -std=c99 -Wall -pedantic -g -I../
 #-I/usr/include/opencv -I/usr/include/opencv2/highgui For OpenCV
 LIB = -lpthread
-OBJ = strain.o resource.o piped.o
+OBJ = strain.o resource.o pressure.o
 HEADERS = $(wildcard *.h)
 RM = rm -f
 
diff --git a/server/sensors/pressure.c b/server/sensors/pressure.c
new file mode 100644
index 0000000..ddb46df
--- /dev/null
+++ b/server/sensors/pressure.c
@@ -0,0 +1,103 @@
+/**
+ * @file pressure.c
+ * @purpose Implementation of Pressure reading functions
+ */
+
+#include "pressure.h"
+#include "../bbb_pin.h"
+#include "../log.h" // For Fatal()
+
+#define PSI_TO_KPA 6.89475729
+
+/**
+ * Get the ADC number of a Pressure sensor
+ * @param id - Id of the sensor
+ * @returns ADC as defined in bbb_pin_defines.h
+ */
+static int Pressure_GetADC(int id)
+{
+	switch (id)
+	{
+		case PRES_HIGH0:
+			return ADC1;
+		case PRES_HIGH1:
+			return ADC3;
+		case PRES_LOW0:
+			return ADC5;
+		default:
+			Fatal("Unknown Pressure id %d", id);
+			return -1; // Should never happen
+	}
+}
+
+/**
+ * Convert an ADC voltage into a Pressure reading
+ * @param id - Sensor ID
+ * @param adc - ADC reading
+ * @returns Pressure in kPa
+ */
+double Pressure_Callibrate(int id, int adc)
+{
+	//double voltage = ADC_TO_VOLTS(adc); // convert reading to voltage
+
+	switch (id)
+	{
+		case PRES_HIGH0:
+		case PRES_HIGH1:
+		{
+			static const double Vs = 5e3; // In mVs
+			static const double Pmin = 0.0;
+			static const double Pmax = 150.0 * PSI_TO_KPA;
+			double Vout = ADC_TO_MVOLTS(adc);
+			return ((Vout - 0.1*Vs)/(0.8*Vs))*(Pmax - Pmin) + Pmin;
+		}	
+		case PRES_LOW0:
+			return (200.0 * (adc / ADC_RAW_MAX));
+		default:
+			Fatal("Unknown Pressure id %d", id);
+			return -1; // Should never happen
+	}
+	
+}
+
+/**
+ * Initialise a Pressure sensor
+ * @param name - Ignored
+ * @param id - The id of the Pressure sensor
+ * @returns true on success, false on error
+ */
+bool Pressure_Init(const char * name, int id)
+{
+	return ADC_Export(Pressure_GetADC(id));
+}
+
+/**
+ * Cleanup a Pressure Sensor
+ * @param id - The id of the sensor to cleanup
+ * @returns true on success, false on failure
+ */
+bool Pressure_Cleanup(int id)
+{
+	ADC_Unexport(Pressure_GetADC(id));
+	return true;
+}
+
+/**
+ * Read a Pressure Sensor
+ * @param id - id of the sensor to read
+ * @param value - Where the value will be stored on a successful read
+ * @returns true on success, false on failure
+ */
+bool Pressure_Read(int id, double * value)
+{
+	//static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+	//pthread_mutex_lock(&mutex);
+	bool result = false;
+	if (ADC_Read(Pressure_GetADC(id), value))
+	{
+		*value = Pressure_Callibrate(id, *value);
+		result = true;
+	}
+	//pthread_mutex_unlock(&mutex);
+	return result;
+}
diff --git a/server/sensors/pressure.h b/server/sensors/pressure.h
new file mode 100644
index 0000000..22d1adc
--- /dev/null
+++ b/server/sensors/pressure.h
@@ -0,0 +1,23 @@
+/**
+ * @file pressure.h
+ * @purpose Declarations for Pressure Sensor functions
+ */
+
+#ifndef _PRESSURE_H
+
+#include "../common.h"
+
+typedef enum
+{
+	PRES_HIGH0,
+	PRES_HIGH1,
+	PRES_LOW0
+} PressureId;
+
+extern bool Pressure_Init(const char * name, int id);
+extern bool Pressure_Cleanup(int id);
+extern bool Pressure_Read(int id, double * value);
+
+#endif //_PRESSURE_H
+
+