Revision 0:2df78a4443cd, committed 2016-04-10

Comitter:

Joseph Radford

Date:

Sun Apr 10 15:47:33 2016 +1000

Commit message:

Initial commit

Changed in this revision

diff -r 000000000000 -r 2df78a4443cd DHT.lib
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DHT.lib	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,1 @@
+http://developer.mbed.org/users/Wimpie/code/DHT/#9b5b3200688f

diff -r 000000000000 -r 2df78a4443cd DS_1337.lib
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DS_1337.lib	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,1 @@
+http://mbed.org/users/loovee/code/DS_1337/#f4f9b627adf9

diff -r 000000000000 -r 2df78a4443cd Handlers/AbstractHandler.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Handlers/AbstractHandler.h	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,34 @@
+#ifndef __ABSTRACT_HANDLER_H__
+#define __ABSTRACT_HANDLER_H__
+
+#include "../timers.h"
+
+/*!
+ * \brief The AbstractHandler class is inherited by all handlers. It forms the basis of any handler, by having
+ * a simple \a run function, called in main.cpp, and a \a setRequest function which is used to set a request
+ * specific to the reimplemented class.
+ */
+class AbstractHandler
+{
+public:
+    AbstractHandler(MyTimers *_timer) : m_timer(_timer) {}
+    ~AbstractHandler() {}
+
+    /*!
+     * \brief run is inherited by each Handler class. It is called from the main while loop in main.cpp.
+     * It runs through the state machine, specific to each Handler class.
+     */
+    virtual void run() = 0; // run the handler
+
+    /*!
+     * \brief setRequest sets a request that the handler will complete when it is able to
+     * \param request unique to the reimplemented class (an enum) that will be completed in the state machine
+     * \param message an optional array of information relevant to the \a request
+     */
+    virtual void setRequest(int request, void *data = 0) = 0;
+
+protected:
+    MyTimers *m_timer;  ///< Handler classes use timers to pause in the state machine, and continue after delay has finished
+};
+
+#endif // __ABSTRACT_HANDLER_H__

diff -r 000000000000 -r 2df78a4443cd Handlers/GprsHandler.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Handlers/GprsHandler.cpp	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,260 @@
+#ifdef ENABLE_GPRS_TESTING
+#include "GprsHandler.h"
+#include "mbed.h"
+#include "config.h"
+#include "UsbComms.h"
+#include "circbuff.h"
+#define TX_GSM P1_27
+#define RX_GSM P1_26
+
+// declare led3 to display GPRS handler state
+extern DigitalOut myled3;
+
+/*
+ * PINPWR to low on Q10 drives 3V3 to Q7, which drives Q5 to ground, which powers VBAT_900, with
+ * either VCC_BUCK or VCC_BAT
+ */
+#define PINPWR                  P1_2
+#define PINONOFF                P1_7
+
+#define REQ_SEND_SMS     0b00000001
+
+#define USB_BUFF_SIZE 256
+
+#define SIM900_SERIAL_TIMEOUT 10000
+
+GprsHandler::GprsHandler(MyTimers * _timer, UsbComms *_usb) : AbstractHandler(_timer)
+{
+    m_serial = new Serial(TX_GSM, RX_GSM);	// create object for UART comms
+    mode = gprs_Start;		// initialise state machine
+
+    m_sim900_pwr = new DigitalOut(PINPWR);		// create pin out for
+    m_sim900_on  = new DigitalOut(PINONOFF);
+    m_reqReg = 0;
+
+    m_usb = _usb;
+    m_rxBuff = new CircBuff(USB_BUFF_SIZE);
+
+    m_atReq = atreq_Test;
+}
+
+GprsHandler::~GprsHandler()
+{
+    // TODO Auto-generated destructor stub
+    delete m_serial;
+    delete m_rxBuff;
+    delete m_sim900_pwr;
+    delete m_sim900_on;
+}
+
+void GprsHandler::run()
+{
+    switch(mode)
+    {
+    case gprs_Start:
+
+        mode = gprs_PowerOff;
+        break;
+
+
+        // POWER HANDLERS
+
+    case gprs_PowerOff:
+        m_sim900_pwr->write(1);				// turn power supply off
+        m_sim900_on->write(1);
+        m_timer->SetTimer(MyTimers::tmr_GprsPower, 500);	// wait to settle
+        mode = gprs_PowerOffWait;
+        break;
+
+    case gprs_PowerOffWait:
+        if (!m_timer->GetTimer(MyTimers::tmr_GprsPower))
+        {
+            mode = gprs_PowerSupplyOn;		// timer has elapsed
+        }
+        break;
+
+    case gprs_PowerSupplyOn:
+        m_sim900_pwr->write(0);		// turn power supply on
+        m_sim900_on->write(0);		// from the ref: "drive the PWRKEY to a low level for 1 second then release."
+
+
+        m_timer->SetTimer(MyTimers::tmr_GprsPower, 1000);	// wait for one second
+        mode = gprs_PowerSupplyOnWait;						// go to wait state
+        break;
+
+    case gprs_PowerSupplyOnWait:
+        if (!m_timer->GetTimer(MyTimers::tmr_GprsPower))
+        {
+            mode = gprs_PowerSwitchOn;		// timer has elapsed
+        }
+        break;
+
+    case gprs_PowerSwitchOn:
+        m_sim900_on->write(1);		// release power key
+        m_timer->SetTimer(MyTimers::tmr_GprsPower, 500);	// wait to settle
+        mode = gprs_PowerSwitchOnWait;
+        break;
+
+    case gprs_PowerSwitchOnWait:
+        if (!m_timer->GetTimer(MyTimers::tmr_GprsPower))
+        {
+            mode = gprs_CheckATReqs;		// timer has elapsed
+        }
+        break;
+
+
+        // REQUEST HANDLERS
+
+    case gprs_CheckATReqs:
+        switch (m_atReq) {
+        case atreq_Test:
+            sprintf((char*)txBuf, "AT\r\n");
+            txBufLen = 4;
+            mode = gprs_PostTx;
+            break;
+
+        case atreq_CheckSMS:
+            sprintf((char*)txBuf, "AT+CMGL=\"ALL\"");
+            txBufLen = 13;
+            mode = gprs_PostTx;
+            break;
+
+        default:
+            m_atReq = atreq_Test;
+        }
+        break;
+
+
+        // TX/RX HANDLERS
+
+    case gprs_PostTx:
+        // use putc, other write functions in serial don't really seem to work
+        for (int i = 0; i < txBufLen; i++) {
+            m_serial->putc(txBuf[i]);
+        }
+
+        // make sure buffer is null terminated before printing to USB
+        txBuf[txBufLen+1] = 0;
+        m_usb->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, txBuf);
+
+        // clear the buffer
+        txBufLen = 0;
+
+        // set timeout
+        m_timer->SetTimer(MyTimers::tmr_GprsRxTx, SIM900_SERIAL_TIMEOUT);
+
+        // wait for a response
+        mode = gprs_WaitRx;
+        break;
+
+    case gprs_WaitRx:
+        if (m_timer->GetTimer(MyTimers::tmr_GprsRxTx))
+        {
+            // we have not timed out yet
+            // we need a generic rx handler here.
+            while (m_serial->readable())
+            {
+                char ch = m_serial->getc();
+
+                // save this to our rx circular buffer
+                m_rxBuff->putc(ch);
+
+                mode = gprs_CheckRx;
+    			wait(0.1);
+            }
+            // we have not timed out, and have not got anything back yet
+            // keep waiting in this state
+        }
+        else {
+        	m_usb->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, (char*)"SIM900 TIMEOUT!");
+            mode = gprs_RxTimeout;
+        }
+        break;
+
+    case gprs_CheckRx:
+        if (m_rxBuff->dataAvailable()) {
+
+            // read out
+            unsigned char s[50];
+            uint16_t len = m_rxBuff->read(s, 50);
+
+            // write to USB
+            m_usb->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, s);
+
+            // process the reply
+            switch(m_atReq) {
+            case atreq_Test:
+                // should have just gotten an ok back
+                bool bOk = false;
+                for (int i = 0; i < (len - 1); i++) {
+                    if ((s[i] == 'O') && (s[i+1] == 'K')) {
+                        bOk = true;
+                    }
+                }
+
+                if (bOk) {
+                    myled3 = 1;
+                    // so we know that comms are definitely OK.
+                    // now check to see what requests need to get fulfilled
+
+                    if (m_reqReg&REQ_SEND_SMS) {
+                        // we want to check what sms is
+                        m_atReq = atreq_SendSMS;
+
+                        m_reqReg &= ~REQ_SEND_SMS;
+                    }
+                    else {
+                        // no requests, but see if there are any received SMSs
+                        m_atReq = atreq_CheckSMS;
+                    }
+                }
+                else {
+                    // did not get the reply we were hoping for.
+                }
+                break;
+
+            default:
+                // todo: handle replies for checking/sending SMSs
+                m_atReq = atreq_Test;
+                break;
+            }
+        }
+        else {
+
+        }
+        m_timer->SetTimer(MyTimers::tmr_GprsRxTx, 2000);
+        // now that we're done here, go check what needs to get sent to the SIM900 next
+        mode = gprs_WaitUntilNextRequest;
+        break;
+        
+    case gprs_WaitUntilNextRequest:
+    	if (!m_timer->GetTimer(MyTimers::tmr_GprsRxTx)) {
+			mode = gprs_CheckATReqs;
+		}
+		break;
+    case gprs_RxTimeout:
+    case gprs_RxError:
+    default:
+        mode = gprs_Start;
+        break;
+
+
+    }
+}
+
+void GprsHandler::setRequest(int request, void *data)
+{
+    m_lastRequest = (request_t)request;
+    switch(request) {
+    case gprsreq_SmsSend:
+        GprsRequest *req = (GprsRequest*)data;
+
+        // make a copy
+        m_lastMessage = *req;     // there are strings, do i have to copy these manually?
+
+        // set the request
+        m_reqReg |= REQ_SEND_SMS;
+        break;
+    }
+}
+#endif

diff -r 000000000000 -r 2df78a4443cd Handlers/GprsHandler.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Handlers/GprsHandler.h	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,112 @@
+#ifndef GPRSHANDLER_H_
+#define GPRSHANDLER_H_
+
+#include "config.h"
+#ifdef ENABLE_GPRS_TESTING
+/*
+ *  This section of the program is currently under development. The rest of the functions
+ * can run wtihout this component by using the ENABLE_GPRS_TESTING flag.
+ */
+
+#include "USBDevice.h"	// need to include this, so that USBSerial has correct typedefs!
+#include "USBSerial.h"
+#include "AbstractHandler.h"
+
+#define GPRS_BUF_LEN 20
+
+#define GPRS_MESSAGE_MAXLEN 160
+#define GPRS_RECIPIENTS_MAXLEN 20
+
+struct GprsRequest
+{
+    char message[GPRS_MESSAGE_MAXLEN];
+    char recipients[GPRS_RECIPIENTS_MAXLEN];
+};
+class UsbComms;
+class CircBuff;
+
+/*!
+ * \brief The GprsHandler class saves recipients and looks after incoming and outgoing messages
+ *
+ * Options: save recipients internally to this class.
+ * Or - request sends a struct that includes recipients list and message string
+ */
+class GprsHandler : public AbstractHandler
+{
+public:
+	GprsHandler(MyTimers * _timer, UsbComms *_usb);
+	virtual ~GprsHandler();
+
+	void run();
+
+    void setRequest(int request, void *data = 0);
+
+    enum request_t{
+        gprsreq_GprsNone,       ///< No request (for tracking what the last request was, this is initial value for that)
+        gprsreq_SmsSend,        ///< got a string to send to recipient(s)
+        gprsreq_SetRecipients   ///< got a string holding the number(s) we want to send
+    };
+
+private:
+    enum mode_t{
+        gprs_Start,          	///< Set up the state machine and the hardware
+
+        // Restart sequence
+        gprs_PowerOff,          ///< Ensure module is powered down first, so we know it is in its initial state
+        gprs_PowerOffWait,      ///< Give module time to power down
+        gprs_PowerSupplyOn,		///< Once module has fully powered down, power back up to begin using it
+        gprs_PowerSupplyOnWait,	///< Give time to power on properly
+        gprs_PowerSwitchOn,
+        gprs_PowerSwitchOnWait,
+
+        gprs_CheckATReqs,       ///< Check was AT request is next
+
+        // read AT+CMGR=?
+        // write AT+CMGS=?
+        gprs_PostTx,            ///< Send the current buffer to SIM900 and setup timeouts
+        gprs_WaitRx,            ///< Wait for a response over serial
+        gprs_CheckRx,           ///< Check the response. Go back into state machine depending on response
+        
+        gprs_WaitUntilNextRequest, 
+
+        gprs_RxTimeout,         ///< no response
+        gprs_RxError            ///< wrong response
+
+
+    };
+    mode_t mode;            ///< the current state in the state machine
+    mode_t returnMode;      ///< the state to go back to when the expected reply returns from the SIM900
+
+    ///
+    /// \brief The at_req enum stores what AT command should be sent/was just sent to the SIM900
+    ///
+    enum at_req {
+        atreq_Test,         ///< Ping the SIM900
+        atreq_CheckSMS,     ///< Check if an SMS is available
+        atreq_SendSMS       ///< Send an SMS, according to m_lastRequest
+    };
+    at_req m_atReq;
+
+    request_t m_lastRequest;
+    GprsRequest m_lastMessage;
+
+    Serial * m_serial; //!< Serial port for comms with SIM900
+
+    DigitalOut * m_sim900_pwr;	//!< pin used to enable the SIM900 power switch
+    DigitalOut * m_sim900_on;	//!< pin used to drive the power key
+
+    uint8_t m_reqReg;   ///< request register
+
+    unsigned char txBuf[GPRS_BUF_LEN];
+    uint16_t txBufLen;
+    unsigned char rxBuf[GPRS_BUF_LEN];
+    
+    UsbComms *m_usb;
+    CircBuff *m_rxBuff;
+    
+};
+
+#endif
+
+#endif /* GPRSHANDLER_H_ */
+

diff -r 000000000000 -r 2df78a4443cd Handlers/GroveDht22.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Handlers/GroveDht22.cpp	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,121 @@
+#include "GroveDht22.h"
+#include "measurementhandler.h"
+
+#define GROVE_NUM_RETRIES 10        // number of retries for reading sensor
+
+DigitalOut grovePwr(P1_3);          // if anything else is interfaced to uart/adc/i2c connectors, this will have to change, as they share this enable line
+
+GroveDht22::GroveDht22(MeasurementHandler *_measure, MyTimers * _timer) : AbstractHandler(_timer), m_measure(_measure)
+{
+    // initialise class variables
+    mode            = dht_StartTurnOff;
+    _lastCelcius    = 0.0f;
+    _lastHumidity   = 0.0f;
+    _lastDewpoint   = 0.0f;
+    _lastError      = ERROR_NONE;
+    _retries        = 0;
+    _newInfo        = 0;
+
+    m_sensor = new DHT(P1_14,SEN51035P);        // Use the SEN51035P sensor
+}
+
+GroveDht22::~GroveDht22()
+{
+    delete m_sensor;
+}
+
+void GroveDht22::run()
+{
+    switch(mode)
+    {
+    case dht_StartTurnOff:
+        powerOn(false);
+        m_timer->SetTimer(MyTimers::tmr_GroveMeasure, 1000);     // leave off for 1 second
+        mode = dht_StartTurnOffWait;
+        break;
+
+    case dht_StartTurnOffWait:
+        if (!m_timer->GetTimer(MyTimers::tmr_GroveMeasure))      // wait until timer has elapsed
+            mode = dht_StartTurnOn;
+        // else come back here
+        break;
+
+    case dht_StartTurnOn:
+        powerOn(true);
+        m_timer->SetTimer(MyTimers::tmr_GroveMeasure, 1000);     // wait one second for sensor to settle
+        mode = dht_StartTurnOnWait;
+        break;
+
+    case dht_StartTurnOnWait:
+        if (!m_timer->GetTimer(MyTimers::tmr_GroveMeasure))      // wait until timer has elapsed
+            mode = dht_TakeMeasurement;
+        // else come back here
+        break;
+
+    case dht_TakeMeasurement:
+        _lastError = (eError)m_sensor->readData();     // take the measurement (todo: see if nonblocking is available)
+        if (_lastError == ERROR_NONE)
+        {
+            _retries = 0;                   // reset retries as measurement was successful
+            _lastCelcius = m_sensor->ReadTemperature(CELCIUS);
+            _lastHumidity = m_sensor->ReadHumidity();
+            _lastDewpoint = m_sensor->CalcdewPoint(_lastCelcius, _lastHumidity);
+            m_timer->SetTimer(MyTimers::tmr_GroveMeasure, 3000); // wait three seconds
+            
+            // add the date time
+            time_t _time = time(NULL); // get the seconds since dawn of time
+            Dht22Result data = {_time, _lastCelcius, _lastHumidity, _lastDewpoint};
+            m_measure->setRequest(MeasurementHandler::measreq_DhtResult, (void*)&data);
+            mode = dht_WaitMeasurement;
+        }
+        else
+        {
+            _retries++;     // there was an error. See if we have reached critical retries
+            if (_retries >= GROVE_NUM_RETRIES)
+            {
+                _retries = 0;
+                mode = dht_StartTurnOff; // restart the sensor
+            }
+            else
+            {
+                // haven't reach critical retries yet, so try again, after waiting
+                m_timer->SetTimer(MyTimers::tmr_GroveMeasure, 3000); // wait three seconds
+                mode = dht_WaitMeasurement;
+            }
+            int sendData = (int)_lastError; // just to make sure nothing funny happens with the enum
+            m_measure->setRequest(MeasurementHandler::measreq_DhtError, (int*)&sendData);
+        }
+        _newInfo = 1;
+        break;
+
+    case dht_WaitMeasurement:
+        if (!m_timer->GetTimer(MyTimers::tmr_GroveMeasure))  // if timer elapsed
+            mode = dht_TakeMeasurement;
+        // else come back here
+        break;
+
+    }
+}
+
+void GroveDht22::setRequest(int request, void *data)
+{
+    // no requests (yet)
+}
+
+// check if there is new information and reset the flag once the check occurs
+unsigned char GroveDht22::newInfo()
+{
+    unsigned char retval = _newInfo;
+    _newInfo = 0;
+    return retval;
+}
+
+// turn the enable pin for the peripheral plugins on the Arch GPRS v2
+// it is active low and acts on Q1
+void GroveDht22::powerOn(unsigned char ON)
+{
+    if (ON)
+        grovePwr = 0;   // active low, will turn power on
+    else
+        grovePwr = 1;   // will turn power off
+}

diff -r 000000000000 -r 2df78a4443cd Handlers/GroveDht22.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Handlers/GroveDht22.h	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,81 @@
+#ifndef __GROVE_DHT_22_H__
+#define __GROVE_DHT_22_H__
+
+#include "DHT.h"
+#include "mbed.h"
+#include "AbstractHandler.h"
+
+class MeasurementHandler;
+
+/*!
+ * \brief The Dht22Result struct is the information read from a Dht22 Grove sensor
+ */
+struct Dht22Result {
+    time_t resultTime;      ///< timestamp of when the result was returned from the Dht22
+    float  lastCelcius;     ///< Temperature result (degC)
+    float  lastHumidity;    ///< Humidity result
+    float  lastDewpoint;    ///< Dewpoint result
+};
+
+/*!
+ * \brief The GroveDht22 class handles the interface to the DHT22 humidity and temperature sensor.
+ *
+ * The state machine checks for errors and retries and will power cycle the sensor if there are
+ * GROVE_NUM_RETRIES number of retries.
+
+ * The state machine also ensures that at least two seconds is left between readings.
+
+ * At any time the parent class can access the last good readings, or the last error.
+
+ * The newInfo flag exists so that the parent can decide to only notify (print to terminal or otherwise) when there
+ * is new information available. Calling the newInfo getter will clear the newInfo flag.
+ */
+class GroveDht22 : public AbstractHandler
+{
+public:
+    GroveDht22(MeasurementHandler *_measure, MyTimers * _timer);
+    ~GroveDht22();
+
+    void run();
+
+    void setRequest(int request, void *data = 0);
+
+    // getters
+    float  lastCelcius()  { return _lastCelcius; }
+    float  lastHumidity() { return _lastHumidity; }
+    float  lastDewPoint() { return _lastDewpoint; }
+    eError lastError()    { return _lastError; }
+    unsigned char newInfo();
+
+private:
+    // state machine
+    typedef enum {
+        dht_StartTurnOff,       ///< Begin by ensuring the sensor is switched off
+        dht_StartTurnOffWait,   ///< Allow it to power down completely
+        dht_StartTurnOn,        ///< Turn the sensor on
+        dht_StartTurnOnWait,    ///< Allow sensor to settle after powering on
+        dht_TakeMeasurement,    ///< Take a measurement, check if valid, update measurment vars, set newInfo
+        dht_WaitMeasurement     ///< Wait for 2 seconds between measurements
+    } mode_t;
+
+    mode_t mode;            ///< The current state in the state machine
+
+    float _lastCelcius;     ///< Last temperature reading from the Dht22 sensor
+    float _lastHumidity;    ///< Last humidity reading from the Dht22 sensor
+    float _lastDewpoint;    ///< Last dewpoint calculation from last temp, humidity vales
+    unsigned char _newInfo; ///< This flag indicates there is new information (an error, or a measurement)
+    int _retries;           ///< Number of bad readings from the Dht22 sensor
+    eError _lastError;      ///< The last error, or lack thereof
+
+    /*!
+     * \brief powerOn powers the Dht22 on or off, by toggling the enable pin
+     * \param ON true to power on, false to power off
+     */
+    void powerOn(unsigned char ON);
+
+    MeasurementHandler *m_measure;  ///< Reference to send measurement results and errors to for handling
+
+    DHT *m_sensor;                  ///< Interface to hardware DHT sensor
+};
+
+#endif // __GROVE_DHT_22_H__

diff -r 000000000000 -r 2df78a4443cd Handlers/SdHandler.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Handlers/SdHandler.cpp	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,224 @@
+#include "SdHandler.h"
+
+#include "GroveDht22.h" // for interpreting the result struct
+#include "circbuff.h"
+
+#define SD_BUFFER_LEN 256u   // length of circular buffers
+
+// define pins for communicating with SD card
+#define PIN_MOSI        P1_22
+#define PIN_MISO        P1_21
+#define PIN_SCK         P1_20
+#define PIN_CS          P1_23
+
+#define DATA_FILE_NAME   "/sd/data.csv"
+#define SYSLOG_FILE_NAME "/sd/log.txt"
+
+// declare led that will be used to express state of SD card
+extern DigitalOut myled2;
+
+SdHandler::SdHandler(MyTimers * _timer) : AbstractHandler(_timer)
+{
+    // init file system and files
+    m_sdfs = new SDFileSystem(PIN_MOSI, PIN_MISO, PIN_SCK, PIN_CS, "sd");
+    m_data = NULL;
+    m_syslog = NULL;
+
+    // initialise circular buffers
+    m_dataLogBuff = new CircBuff(SD_BUFFER_LEN);
+    m_sysLogBuff  = new CircBuff(SD_BUFFER_LEN);
+    
+    mode = sd_Start;
+    m_lastRequest = sdreq_SdNone;
+}
+
+SdHandler::~SdHandler()
+{
+    delete m_dataLogBuff;
+    delete m_sysLogBuff;
+}
+
+void SdHandler::run()
+{
+    uint16_t tempInt = 0, tempInt2 = 0;
+
+    unsigned char tempBuff[SD_BUFFER_LEN];
+
+    switch(mode)
+    {
+    case sd_Start:              /* Set up the state machine */
+        // check if card is inserted??
+        //m_sdfs->unmount();
+        // close both files if necessary
+        if (m_data != NULL)
+            fclose(m_data);
+        if (m_syslog != NULL)
+            fclose(m_syslog);
+
+        m_data = NULL;
+        m_syslog = NULL;
+
+        //mkdir("/sd", 0777);
+        //m_sdfs->mount();
+        m_data = fopen(DATA_FILE_NAME, "a");
+        m_syslog = fopen(SYSLOG_FILE_NAME, "a");
+
+        if ((m_data != NULL) && (m_syslog != NULL))
+        {
+            // both opened successfully
+            fprintf(m_syslog, "Unit booted OK\n");
+            fclose(m_syslog);
+            
+            // write the header in on startup
+            fprintf(m_data, "Timestamp, Temperature (degC), Humidity (pc), Dewpoint\n");            
+            fclose(m_data);
+            mode = sd_CheckSysLogBuffer;
+        }
+        break;
+
+    case sd_CheckSysLogBuffer:     /* See if any data should be written to the log file */
+        if (m_sysLogBuff->dataAvailable())
+        {
+            tempInt = m_sysLogBuff->read(tempBuff, SD_BUFFER_LEN);
+            tempInt2 = fprintf(m_syslog, (const char*)tempBuff);
+            if (tempInt == tempInt2)
+            {
+                // success
+                mode = sd_CheckDataLogBuffer;
+            }
+            else
+            {
+                // something went wrong
+                m_timer->SetTimer(MyTimers::tmr_SdWaitError, 2000);
+                mode = sd_WaitError;
+            }
+        }
+        else {
+            mode = sd_CheckDataLogBuffer;
+        }
+        break;
+
+    case sd_CheckDataLogBuffer:    /* See if any data should be written to the data file */
+        if (m_dataLogBuff->dataAvailable())
+        {            
+            m_data = fopen(DATA_FILE_NAME, "a");
+
+            if (m_data != NULL)
+            {
+                // opened successfully            
+                tempInt = m_dataLogBuff->read(tempBuff, SD_BUFFER_LEN);
+                tempInt2 = fprintf(m_data, (const char*)tempBuff);            
+                fclose(m_data);
+                if (tempInt == tempInt2)
+                {
+                    // success
+                    myled2 = 0;
+                    mode = sd_CheckSysLogBuffer;
+                }
+                else
+                {
+                    // something went wrong
+                    m_timer->SetTimer(MyTimers::tmr_SdWaitError, 2000);
+                    mode = sd_WaitError;
+                }
+            }            
+            else
+            {
+                // something went wrong
+                m_timer->SetTimer(MyTimers::tmr_SdWaitError, 2000);
+                mode = sd_WaitError;
+            }
+        }
+        else {
+            mode = sd_CheckSysLogBuffer;
+        }
+        break;
+
+    case sd_WaitError:     /* Many fails, much wow, wait for a while */
+        if (!m_timer->GetTimer(MyTimers::tmr_SdWaitError))
+        {
+            // timer has elapsed. go back to start.
+            mode = sd_Start;
+        }
+        break;
+    }
+}
+
+void SdHandler::setRequest(int request, void *data)
+{
+    request_t req = (request_t)request;
+    m_lastRequest = req;
+    switch(req) {
+    case sdreq_SdNone:
+    
+        break;
+    case sdreq_LogData:
+            
+        myled2 = 1;
+        // have received the data struct. cast it
+        Dht22Result *result = (Dht22Result*)data;
+        
+        // write things to sd card buffer
+        char s[50]; // buffer
+        int temp;   // length of buffer
+        csvStart(result->resultTime);
+        temp = sprintf(s, "%4.2f", result->lastCelcius);
+        csvData(s, temp);
+        temp = sprintf(s, "%4.2f",    result->lastHumidity);
+        csvData(s, temp);
+        temp = sprintf(s, "%4.2f",    result->lastDewpoint);
+        csvData(s, temp);
+        csvEnd();
+        break;
+    case sdreq_LogSystem:
+        char *str = (char*)data;
+        logEvent(str);
+        break;
+    }
+}
+
+void SdHandler::csvStart(time_t _time)
+{
+    unsigned char sTemp[17];
+    
+    
+    // extract time_t to time info struct
+    
+    struct tm * timeinfo = localtime(&_time);
+    
+    // print the formatted timestamp at the start of terminalBuffer, with comma
+    sprintf((char*)&sTemp[0], "%04d%02d%02d %02d%02d%02d,", (timeinfo->tm_year + 1900),
+                                                    (timeinfo->tm_mon + 1),
+                                                    timeinfo->tm_mday,
+                                                    timeinfo->tm_hour,
+                                                    timeinfo->tm_min,
+                                                    timeinfo->tm_sec);
+                      
+    sTemp[16] = 0;
+                          
+    m_dataLogBuff->add(sTemp);
+}
+
+void SdHandler::csvData(const char * s, int len)
+{
+    unsigned char sTemp[50];
+    int idx = 0;
+    // add a column to the buffer
+    sprintf((char*)&sTemp[idx], s);
+    idx += len;
+    sTemp[idx++] = ',';
+    sTemp[idx] = 0;
+    m_dataLogBuff->add(sTemp);
+}
+
+void SdHandler::csvEnd()
+{
+    unsigned char sTemp[2];
+    sTemp[0] = '\n';
+    sTemp[1] = 0;
+    m_dataLogBuff->add(sTemp);
+}
+
+void SdHandler::logEvent(const char * s)
+{
+}

diff -r 000000000000 -r 2df78a4443cd Handlers/SdHandler.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Handlers/SdHandler.h	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,59 @@
+#ifndef __SD_HANDLER_H__
+#define __SD_HANDLER_H__
+
+#include "SDFileSystem.h"
+#include "AbstractHandler.h"
+
+class CircBuff;
+
+/*!
+ * \brief The SdHandler class writes messages to file and handles SD card status
+ * 
+ * A data CSV file is written with timestamps and the result from the GroveDht22.
+ * A system log, not yet fully implemented, tracks system events for debugging purposes.
+ */
+class SdHandler : public AbstractHandler
+{
+public:
+    SdHandler(MyTimers * _timer);
+    ~SdHandler();
+
+    void run();
+
+    void setRequest(int request, void *data = 0);
+
+    bool sdOk();
+
+    enum request_t {
+        sdreq_SdNone,       ///< to init
+        sdreq_LogData,      ///< Send struct containing a result and timestamp. This turns it into a line in a csv file
+        sdreq_LogSystem     ///< write raw string to system logging file (errors, events, etc)
+    };
+
+private:
+    SDFileSystem * m_sdfs;
+    FILE * m_data;
+    FILE * m_syslog;
+
+    enum mode_t{
+        sd_Start,                   ///< Set up the state machine
+        sd_CheckSysLogBuffer,       ///< See if any data should be written to the log file
+        sd_CheckDataLogBuffer,      ///< See if any data should be written to the data file
+
+        sd_WaitError                ///< Error. wait for a while
+    };
+    mode_t mode;
+
+    request_t m_lastRequest;
+    
+    // helpers
+    void csvStart(time_t time);
+    void csvData(const char * s, int len);
+    void csvEnd();
+    void logEvent(const char * s);
+    
+    CircBuff *m_dataLogBuff;        ///< Data waiting to be written to the data CSV file
+    CircBuff *m_sysLogBuff;         ///< Data waiting to be written to the system log file (not yet implemented)
+};
+
+#endif // __SD_HANDLER_H__

diff -r 000000000000 -r 2df78a4443cd Handlers/UsbComms.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Handlers/UsbComms.cpp	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,125 @@
+#include "UsbComms.h"
+#include "mbed.h"
+
+#include "USBDevice.h"
+#include "USBSerial.h"
+
+#include "circbuff.h"
+
+#define USB_CIRC_BUFF 256
+
+extern DigitalOut myled1; // this led is used to notify state of USB comms
+
+UsbComms::UsbComms(MyTimers *_timer) : AbstractHandler(_timer)
+{
+    mode = usb_Start;
+
+    m_circBuff = new CircBuff(USB_CIRC_BUFF);
+
+    // Declare serial port for communication with PC over USB
+    _serial = new USBSerial;
+}
+
+UsbComms::~UsbComms()
+{
+    delete _serial;
+    delete m_circBuff;
+}
+
+void UsbComms::run()
+{
+    unsigned char temp;
+    switch(mode) {
+    case usb_Start:
+        mode = usb_CheckInput;
+        break;
+    case usb_CheckInput:
+        if (_serial->readable()) {
+            _serial->getc();
+            // todo: do something with it! this is where config events are started
+            // uncomment to print a message confirming input
+            // _serial->writeBlock((unsigned char*)"getc\r\n", 6);
+            //mode = usb_WaitForInput;
+            mode = usb_CheckOutput;
+        } else {
+            mode = usb_CheckOutput;
+        }
+        break;
+    case usb_CheckOutput:
+        if (m_circBuff->dataAvailable() && _serial->writeable()) {
+            // ensure only 64 bytes or less are written at a time
+            unsigned char s[TX_USB_MSG_MAX];
+            int len = m_circBuff->read(s, TX_USB_MSG_MAX);
+            _serial->writeBlock((unsigned char*)s, len);
+            myled1 = 1;
+
+        } else {
+            myled1 = 0;
+        }
+        mode = usb_CheckInput;
+        break;
+    }
+}
+
+void UsbComms::setRequest(int request, void *data)
+{
+    request_t req = (request_t)request;
+
+    switch (req) {
+    case usbreq_PrintToTerminal:
+        printToTerminal((char*)data);
+        break;
+    case usbreq_PrintToTerminalTimestamp:
+        printToTerminalEx((char*)data);
+        break;
+    }
+}
+
+void UsbComms::printToTerminal(char *s)
+{
+    // simply add this string to the circular buffer
+    m_circBuff->add((unsigned char*)s);
+}
+
+// print the message, but prepend it with a standard timestamp
+// YYYYMMDD HHMMSS: 
+// 01234567890123456
+void UsbComms::printToTerminalEx(char *s)
+{
+    unsigned char tempBuff[TX_USB_BUFF_SIZE];
+    // this won't work! needs to be a circular buffer...
+    uint16_t sSize = 0, i = 0, j = 0;
+
+    // get the length of the passed array (it should be null terminated, but include max buffer size for caution)
+    for (sSize = 0; (sSize < TX_USB_BUFF_SIZE) && (s[sSize] != 0); sSize++);
+
+
+    time_t _time = time(NULL); // get the seconds since dawn of time
+
+    // extract time_t to time info struct
+    struct tm * timeinfo = localtime(&_time);
+
+    // print the formatted timestamp at the start of terminalBuffer
+    sprintf((char*)&tempBuff[0], "%04d%02d%02d %02d%02d%02d:", (timeinfo->tm_year + 1900),
+            (timeinfo->tm_mon + 1),
+            timeinfo->tm_mday,
+            timeinfo->tm_hour,
+            timeinfo->tm_min,
+            timeinfo->tm_sec);
+
+
+    // copy the string into the remainder of the terminal buffer
+    for (i = 16; i < (16 + sSize); i++) {
+        tempBuff[i] = s[j++];
+    }
+
+    // add a carriage return and new line to the output buffer
+    tempBuff[i++] = '\r';
+    tempBuff[i++] = '\n';
+    tempBuff[i++] = 0;
+
+    // add it to the circular buffer
+    m_circBuff->add(tempBuff);
+}
+
+

diff -r 000000000000 -r 2df78a4443cd Handlers/UsbComms.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Handlers/UsbComms.h	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,51 @@
+#ifndef __USB_COMMS_H__
+#define __USB_COMMS_H__
+#include "AbstractHandler.h"
+
+#define TX_USB_MSG_MAX 64u       // only send 64 bytes at a time
+#define TX_USB_BUFF_SIZE 256u    // the tx buffer can hold up to 256 bytes
+
+class USBSerial;
+class CircBuff;
+
+/*!
+ * \brief The UsbComms class handles input and output for the serial port connected to a PC
+ * The main run() function cycles through checking for input and copying to a buffer to be handled,
+ * and checking the output buffer to see if there is anything to be sent out.
+ *
+ * Data can be queued for output by copying it to the circular buffer
+ */
+class UsbComms : public AbstractHandler
+{
+public:
+    UsbComms(MyTimers *_timer);
+    ~UsbComms();
+
+    void run();
+
+    void setRequest(int request, void *data = 0);
+    
+    enum request_t{
+        usbreq_PrintToTerminal,         ///< Print to terminal normally
+        usbreq_PrintToTerminalTimestamp ///< Print to terminal, including the timestamp
+    };
+
+private:
+    USBSerial *_serial;         ///< Interface to the serial port
+    CircBuff *m_circBuff;       ///< Data waiting to be printed to the serial port
+
+    // state machine
+    enum mode_t{
+        usb_Start,          ///< Set up the state machine
+        usb_CheckInput,     ///< See if any data is waiting to be read in - currently does not process anything
+        usb_CheckOutput,    ///< See if any data should be sent over serial
+    };
+    mode_t mode;
+    
+    // helpers
+    void printToTerminal(char *s);  // raw
+    void printToTerminalEx(char *s); // add timestamp
+};
+
+
+#endif

diff -r 000000000000 -r 2df78a4443cd Handlers/measurementhandler.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Handlers/measurementhandler.cpp	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,234 @@
+#include "measurementhandler.h"
+#include "mbed.h"
+#include "SdHandler.h"
+#include "UsbComms.h"
+
+// declare led4 so we can flash it to reflect state of this handler
+extern DigitalOut myled4;
+
+// flags for the request register
+#define REQ_RESULT 0b00000001
+#define REQ_ERROR  0b00000010
+#ifdef ENABLE_GPRS_TESTING
+#define REQ_SMS    0b00000100
+#endif
+
+#ifdef ENABLE_GPRS_TESTING
+MeasurementHandler::MeasurementHandler(SdHandler *_sd, UsbComms *_usb, GprsHandler *_gprs, MyTimers *_timer)
+    : AbstractHandler(_timer), m_sd(_sd), m_usb(_usb), m_gprs(_gprs)
+#else
+MeasurementHandler::MeasurementHandler(SdHandler *_sd, UsbComms *_usb, MyTimers *_timer)
+    : AbstractHandler(_timer), m_sd(_sd), m_usb(_usb)
+#endif
+{
+    m_lastError         = ERROR_NONE;
+    mode                = meas_Start;
+    m_lastRequest       = measreq_MeasReqNone;
+    m_flashOn           = false;
+    m_requestRegister   = 0;
+
+#ifdef ENABLE_GPRS_TESTING
+    for (int i = 0; i < GPRS_RECIPIENTS_MAXLEN; i++) {
+        m_lastSender[i] = 0;
+    }
+#endif
+}
+
+void MeasurementHandler::run()
+{
+    switch(mode) {
+    case meas_Start:
+        // start here, and come back here if an error has been flushed out and waited
+        mode = meas_CheckRequest;
+        break;
+
+    case meas_CheckRequest:
+        if (m_requestRegister) {
+            // check what has been requested, starting from most highest priority
+            
+#ifdef ENABLE_GPRS_TESTING
+            if (m_requestRegister&REQ_SMS) {
+                // an SMS has been requested
+                mode = meas_PostStateSMS;
+            }
+            else if (m_requestRegister&REQ_RESULT) {
+#else
+            if (m_requestRegister&REQ_RESULT) {
+#endif
+                // a result has been sent, we need to post it
+                mode = meas_PostResult;
+            }
+            else if (m_requestRegister&REQ_ERROR) {
+                // an error has been sent, we need to post it
+                mode = meas_PostError;
+            }
+            else {
+                // something went wrong, a flag was set that isn't defined
+                m_requestRegister = 0;
+                mode = meas_FlashTimer;
+            }
+        }
+        else {
+            // no requests, check if running led needs to be flashed
+            mode = meas_FlashTimer;
+        }
+        break;
+
+#ifdef ENABLE_GPRS_TESTING
+    case meas_PostStateSMS:
+        if (m_requestRegister&REQ_SMS) {
+            char s[64];
+            // usb print
+            sprintf(s, "Temperature is %4.2f degC\nHumidity is %4.2f pc\nDew point is %4.2f", m_lastResult.lastCelcius, m_lastResult.lastHumidity, m_lastResult.lastDewpoint);
+
+            GprsRequest req;
+            strcpy(req.message, s);
+            strcpy(req.recipients, m_lastSender);
+            m_gprs->setRequest(GprsHandler::gprsreq_SmsSend, &req);
+
+            // clear the request reqister's sms flag
+            m_requestRegister &= ~REQ_SMS;
+        }
+        mode = meas_CheckRequest;
+        break;
+#endif
+
+    case meas_PostResult:
+        if (m_requestRegister&REQ_RESULT) {
+            // we have a result, post it
+
+            // TODO: check when the last result came in. if it has not been very long (< 5s? < 1s?) avoid posting, so we don't hammer it
+
+            char s[50];
+            // usb print
+            sprintf(s, "Temperature is %4.2f degC", m_lastResult.lastCelcius);
+            m_usb->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, s);
+            sprintf(s, "Humidity is %4.2f pc",      m_lastResult.lastHumidity);
+            m_usb->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, s);
+            sprintf(s, "Dew point is %4.2f ",    m_lastResult.lastDewpoint);
+            m_usb->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, s);
+            
+            // post to SD card
+            m_sd->setRequest(SdHandler::sdreq_LogData, &m_lastResult);
+
+            // clear the request
+            m_requestRegister &= ~REQ_RESULT;
+        }
+
+        // go back to check if there are more requests
+        mode = meas_CheckRequest;
+        break;
+
+
+    case meas_PostError:
+        if (m_requestRegister&REQ_ERROR) {
+            // there is an error, check the value of it and post the corresponding string to USB
+            // TODO: post to SD syslog
+            switch (m_lastError)
+            {
+            case BUS_BUSY:
+                m_usb->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, (char*)"BUSY!");
+                break;
+            case ERROR_NOT_PRESENT:
+                m_usb->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, (char*)"NOT PRESENT");
+                break;
+            case ERROR_ACK_TOO_LONG:
+                m_usb->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, (char*)"TOO LONG");
+                break;
+            case ERROR_SYNC_TIMEOUT:
+                m_usb->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, (char*)"SYNC TIMEOUTr\n");
+                break;
+            case ERROR_DATA_TIMEOUT:
+                m_usb->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, (char*)"DATA TIMEOUT");
+                break;
+            case ERROR_CHECKSUM:
+                m_usb->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, (char*)"CHECKSUM");
+                break;
+            case ERROR_NO_PATIENCE:
+                m_usb->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, (char*)"NO PATIENCE!");
+                break;
+            default:
+                m_usb->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, (char*)"UNKNOWN");
+                break;
+            }
+
+            // we have posted it, clear the flag
+            m_requestRegister &= ~REQ_ERROR;
+        }
+        // check if there are any more requests
+        mode = meas_CheckRequest;
+        break;
+        
+    case meas_FlashTimer:
+        // flash timer to know that we are still alive.        
+        if (!m_timer->GetTimer(MyTimers::tmr_MeasFlash)) {      // wait until timer has elapsed
+            if (m_flashOn) {
+                // turn off
+                myled4 = 0;
+                m_timer->SetTimer(MyTimers::tmr_MeasFlash, 2000); // stay off for 2 seconds
+                m_flashOn = false;
+            }
+            else {
+                // turn on
+                myled4 = 1;
+                m_timer->SetTimer(MyTimers::tmr_MeasFlash, 1000); // stay on for 1 second
+                m_flashOn = true;
+            }
+                
+        }
+        mode = meas_CheckRequest;
+        break;
+
+    case meas_WaitError:
+        // TODO: timer
+        mode = meas_Start;
+        break;
+    }
+}
+
+void MeasurementHandler::setRequest(int request, void *data)
+{
+    m_lastRequest = (request_t)request;
+    switch(request) {
+    case measreq_DhtResult:
+        // this should contain time as well
+        Dht22Result *result = (Dht22Result*)data;
+
+        // copy the structure into our own structure
+        m_lastResult = *result;
+
+        // set the request
+        m_requestRegister |= REQ_RESULT;
+
+        break;
+
+    case measreq_DhtError:
+        int *iResult = (int*)data;
+        m_lastError = *iResult;
+        m_requestRegister |= REQ_ERROR;
+
+        break;
+
+#ifdef ENABLE_GPRS_TESTING
+    case measreq_Status:
+        // need to send SMS of last result
+        // the sender's number is the sent data
+        char *sender = (char*)data;
+
+        int i = 0;
+        // copy the sender's number
+        for (i = 0; (i < GPRS_RECIPIENTS_MAXLEN) && (sender[i] != 0); i++) {
+            m_lastSender[i] = sender[i];
+        }
+
+        // set the rest of the destination array to null
+        for (i; i < GPRS_RECIPIENTS_MAXLEN; i++) {
+            m_lastSender[i] = 0;
+        }
+
+        // set the request
+        m_requestRegister |= REQ_SMS;
+        break;
+#endif
+    }
+}

diff -r 000000000000 -r 2df78a4443cd Handlers/measurementhandler.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Handlers/measurementhandler.h	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,94 @@
+#ifndef MEASUREMENTHANDLER_H
+#define MEASUREMENTHANDLER_H
+
+#include "AbstractHandler.h"
+#include "GroveDht22.h"
+#include "config.h"
+#ifdef ENABLE_GPRS_TESTING
+#include "GprsHandler.h"
+#endif
+
+class SdHandler;
+class UsbComms;
+
+
+/*!
+ * \brief The MeasurementHandler class forms the link between data generation and data output, and stores settings.
+ *
+ * Receives requests from \a GroveDht22 when a new measurement has been taken or error has occurred. This handler then
+ * sends that information on to \a UsbComms for printing that information to terminal and \a SdHandler for printing
+ * that information to the CSV data file.
+ *
+ * This handler also determines if the necessary conditions have been met to send an SMS. This is based on last measurement,
+ * the set alert threshold, and time since last alert was sent. An SMS is sent using \a GprsHandler.
+ *
+ * Other requests from inputs asking for current measurement states (such as the latest measurement) may come from \a UsbComms
+ * or \a GprsHandler. The string inspection and matching is handled here, and responses sent to the data outputs.
+ *
+ *
+ * Flashes LED4 constantly to inform that normal operation is occurring.
+ */
+class MeasurementHandler : public AbstractHandler
+{
+public:
+#ifdef ENABLE_GPRS_TESTING
+    MeasurementHandler(SdHandler *_sd, UsbComms *_usb, GprsHandler *_gprs, MyTimers *_timer);
+#else
+    MeasurementHandler(SdHandler *_sd, UsbComms *_usb, MyTimers *_timer);
+#endif
+
+    void run();
+
+    void setRequest(int request, void *data = 0);
+
+    Dht22Result lastResult() const { return m_lastResult; }
+
+    enum request_t{
+        measreq_MeasReqNone,        ///< No request (for tracking what the last request was, this is initial value for that)
+        measreq_DhtResult,          ///< Dht22 returned with a result
+        measreq_DhtError,           ///< Dht22 returned with an error
+#ifdef ENABLE_GPRS_TESTING
+        measreq_Status,             ///< We got an SMS asking for the status (time, last error, last result)
+#endif
+    };
+
+private:
+    SdHandler *m_sd;            ///< Reference to write to SD card
+    UsbComms *m_usb;            ///< Reference to write to USB serial port
+
+#ifdef ENABLE_GPRS_TESTING
+    GprsHandler *m_gprs;        ///< Reference to write to GPRS (SMS)
+#endif
+
+    Dht22Result m_lastResult;   ///< Copy of the last result that came from Dht22
+    int  m_lastError;           ///< Copy of the last error that came from Dht22
+
+#ifdef ENABLE_GPRS_TESTING
+    char m_lastSender[GPRS_RECIPIENTS_MAXLEN];         ///< The last sender of an SMS
+#endif
+
+    bool m_flashOn;             ///< LED is currently on when true
+
+    enum mode_t{
+        meas_Start,             ///< Set up the state machine
+        meas_CheckRequest,      ///< Check request register
+
+#ifdef ENABLE_GPRS_TESTING
+        meas_PostStateSMS,      ///< Send an SMS of the last result and state
+#endif
+        meas_PostResult,        ///< Write the last Grove result to SD and USB
+        meas_PostError,         ///< Write the last Grove error to USB (and in future, SD syslog)
+
+        meas_FlashTimer,        ///< Flash an LED on and off so user knows device is still running
+
+        meas_WaitError          ///< Lots of fails, wait for a while
+    };
+    mode_t mode;
+
+    request_t m_lastRequest;    ///< tracks if result or error was the last request
+
+    uint8_t m_requestRegister;  ///< contains the current pending requests as bitwise flags
+
+};
+
+#endif // MEASUREMENTHANDLER_H

diff -r 000000000000 -r 2df78a4443cd SDFileSystem.lib
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SDFileSystem.lib	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,1 @@
+http://developer.mbed.org/teams/mbed/code/SDFileSystem/#7b35d1709458

diff -r 000000000000 -r 2df78a4443cd USBDevice.lib
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/USBDevice.lib	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/USBDevice/#d17693b10ae6

diff -r 000000000000 -r 2df78a4443cd circbuff.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/circbuff.cpp	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,106 @@
+#include "circbuff.h"
+
+CircBuff::CircBuff(uint16_t buffSize)
+{
+    // set up the buffer with parsed size
+    m_buffSize = buffSize;
+    m_buf = new unsigned char [m_buffSize];
+    for (int i = 0; i < m_buffSize; i++) {
+        m_buf[i] = 0;
+    }
+
+    // init indexes
+    m_start = 0;
+    m_end   = 0;
+}
+
+CircBuff::~CircBuff()
+{
+    delete m_buf;
+}
+
+void CircBuff::putc(unsigned char c)
+{
+    // get the remaining space left in the buffer by checking end and start idx
+    uint16_t remSize = remainingSize();
+
+    // check we have enough room for the new array passed in
+    if (remSize == 0) {
+        return;
+    }
+
+    // else copy the byte in
+    m_buf[m_end++] = c;
+    if (m_end == m_buffSize) {
+        m_end = 0;  // wrap around
+    }
+
+}
+
+void CircBuff::add(unsigned char *s)
+{
+    // check if can write? How to check if we have connected.
+    uint16_t sSize = 0, i = 0, j = 0;
+
+    // get the length of the passed array (it should be null terminated, but include max buffer size for caution)
+    for (sSize = 0; (sSize < m_buffSize) && (s[sSize] != 0); sSize++);
+
+    // get the remaining space left in the buffer by checking end and start idx
+    uint16_t remSize = remainingSize();
+
+    // check we have enough room for the new array passed in
+    if (sSize > remSize) {
+        return;
+    }
+
+    // copy the array in
+    for (i = 0; i < sSize; i++) {
+        m_buf[m_end++] = s[i];
+        if (m_end == m_buffSize) {
+            m_end = 0;  // wrap around
+        }
+    }
+}
+
+uint16_t CircBuff::remainingSize()
+{
+    // get the remaining space left in the buffer by checking end and start idx
+    uint16_t retval = 0;
+    if (m_start == m_end) {
+        retval = m_buffSize;
+    }
+    else if (m_start < m_end) {
+        // the distance between the start and end point
+        // subtract that from the total length of the buffer
+        retval = m_buffSize - (m_end - m_start);
+    }
+    else {
+        // the amount of space left is whatever is between the end point and the start point
+        retval = m_start - m_end;
+    }
+    return retval;
+}
+
+uint16_t CircBuff::read(unsigned char *s, uint16_t len)
+{
+    if (m_start == m_end) {
+        return 0; // there is nothing stored in the circular buffer
+    }
+
+    // start copying the desired amount over
+    for (int i = 0; i < len; i++) {
+        s[i] = m_buf[m_start++];
+        
+        if (m_start == m_buffSize) {
+            m_start = 0;    // wrap start pointer
+        }
+
+        if (m_start == m_end) {
+            s[++i] = 0;
+            return (i); // we have reached the end of the buffer
+        }
+    }
+    return len;
+}
+
+

diff -r 000000000000 -r 2df78a4443cd circbuff.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/circbuff.h	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,46 @@
+#ifndef __CIRC_BUFF_H__
+#define __CIRC_BUFF_H__
+
+#include "mbed.h"
+
+/*!
+ * \brief The CircBuff class writes in and reads out byte arrays into a circular buffer
+ */
+class CircBuff {
+public:
+    CircBuff(uint16_t buffSize = 256);
+    ~CircBuff();
+
+    /*!
+     * \brief putc adds a single byte, \a c, into the array
+     * \param c is the byte copied into the circular buffer.
+     */
+    void putc(unsigned char c);
+
+    /*!
+     * \brief add adds \a s into the buffer, up until the NULL byte
+     * \param s is the byte array copied into the buffer
+     */
+    void add(unsigned char *s);
+
+    /*!
+     * \brief read puts the current data from the buffer into \a s
+     * \param s is the reference buffer to copy current data into. Caller's responsibility to make it the correct size
+     * \param len is the number of bytes to copy into \a s
+     * \return the number of bytes copied into \a s. Will be less than \a len if there was less data in the buffer.
+     */
+    uint16_t read(unsigned char *s, uint16_t len);
+    bool dataAvailable() { return (m_start != m_end); }
+    
+
+private:
+    uint16_t m_start;       ///< The start index of the circular buffer, where the current data starts
+    uint16_t m_end;         ///< The end index, where the current data goes to
+    unsigned char *m_buf;   ///< the byte array
+    uint16_t m_buffSize;    ///< size of \a m_buf
+    
+    // helper
+    uint16_t remainingSize();
+};
+
+#endif // __CIRC_BUFF_H__

diff -r 000000000000 -r 2df78a4443cd config.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/config.h	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,11 @@
+#ifndef CONFIG_H_
+#define CONFIG_H_
+
+/*
+ * This file contains global definitions to configure the program
+ */
+
+// uncomment this to continue development and testing with GPRS
+// #define ENABLE_GPRS_TESTING
+
+#endif /* CONFIG_H_ */

diff -r 000000000000 -r 2df78a4443cd main.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,205 @@
+/*!
+ * Project:     Humidity SMS Alert
+ * Author:      Joseph Radford
+ * Date start:  January 2016
+ * Date mod:
+ * Target:      Arch GPRS V2
+ * Peripherals: SD Card
+ *              SIM Card
+ *              Grove Humidity and Temperature Sensor Pro (DHT22 on a breakout board)
+ *
+ *
+ * Takes intermittent readings from the humidity temperature sensor. These are written to a timestamped CSV file
+ * on the SD card and printed over serial if there is a connection to a terminal window (Screen on Linux, Putty on Windows, etc)
+ *
+ * When conditions have been met, an SMS alert is sent notifying the recipient of the last sensor readings.
+ *
+ * States can be requested, and configurations changed, by sending requests over USB serial or SMS.
+ *
+ * Inputs:
+ * \a GroveDht22
+ *
+ * Outputs:
+ * \a SdHandler
+ *
+ *
+ * Inputs and outputs:
+ * \a GprsHandler
+ * \a UsbComms
+ *
+ * Linker:
+ * \a MeasurementHandler
+ *
+ * 10/04/2016 v0.0.1 - Writes timestamped humidity data to an SD card
+ *
+ * Issues:
+ * Stops communicating over USB after ~10 mins. 
+ * Will not work if USB not present.
+ * Will not work if SD card is not present
+ * GPRS yet to be implemented
+ * RTC is set to 01/01/2000 00:00:00 at startup. No way of setting it yet.
+ */
+
+#include "config.h"
+
+#include "mbed.h"
+#include "math.h"
+
+// Clocks and timers
+#include "DS1337.h"
+#include "rtc.h"
+#include "timers.h"
+
+// Handlers
+#include "Handlers/GroveDht22.h"
+#include "Handlers/UsbComms.h"
+#include "Handlers/SdHandler.h"
+#include "Handlers/measurementhandler.h"
+
+#ifdef ENABLE_GPRS_TESTING
+#include "Handlers/GprsHandler.h"
+#endif
+
+/* Declare hardware classes */
+ 
+DigitalOut myled1(LED2);    ///< startup, and USB handler when writing occurring (right most)
+DigitalOut myled2(LED3);    ///< SD handler - on when buffer pending, off when written. If error, will be on as buffer won't clear
+DigitalOut myled3(LED4);    ///< GPRS handler information
+DigitalOut myled4(LED1);    ///< measurement handler flashes, periodically to inform running (left most)
+
+//DigitalOut myenable(P0_6);
+
+DS1337 * RTC_DS1337;        ///< RTC interface class
+
+I2C i2c(P0_5, P0_4);        ///< I2C comms - this is required by the RTC - do NOT change the name of the instance
+
+
+/* Declare helpers */
+MyTimers *mytimer;         ///< declare timers class - required for other classes to use timers (do not change name)
+
+
+/* Declare handlers */
+GroveDht22          *grove;         ///< grove humidity sensor handler class
+UsbComms            *usbcomms;      ///< reading and writing to usb
+SdHandler           *sdhandler;     ///< Writing data to a file on SD
+MeasurementHandler  *measure;       ///< Handle measurements, and route data to the user and user to configuration
+
+#ifdef ENABLE_GPRS_TESTING
+GprsHandler * gprs; ///< Reading and writing to the SIM900
+#endif
+
+#ifdef ENABLE_GPRS_TESTING
+#define NUM_HANDLERS 5
+#else
+#define NUM_HANDLERS 4
+#endif
+
+#define PROGRAM_TITLE   "Arch GPRS V2 Alert and Request"
+#define PROGRAM_INFO    "v0.0.1, released 09/04/2016"
+
+/*!
+ * \brief main pulses LED1, creates all classes, pulses LED1, then runs through all handlers forever
+ * \return
+ */
+int main()
+{
+    /* start up sequence, so we know we reached main */
+    myled1 = 1;
+    wait(0.2);
+    myled1 = 0;
+    wait(0.2);
+    myled1 = 1;
+    wait(0.2);
+    myled1 = 0;
+    wait(1);
+    myled1 = 1;
+    wait(0.2);
+    myled1 = 0;
+    wait(0.2);
+    myled1 = 1;
+    wait(0.2);
+    myled1 = 0;
+    wait(1);
+    
+    /* Declare all classes */
+
+    // create MyTimers object, which can be used for waiting in handlers
+    mytimer = new MyTimers();
+
+    // RTC interface class
+    RTC_DS1337 = new DS1337();
+    attach_rtc(&my_rtc_read, &my_rtc_write, &my_rtc_init, &my_rtc_enabled);
+
+    // set the time to the start of the year 2000, by default
+    // this will be removed when time can be set, so that time is not reset each time the program starts.
+    tm timeinfo;
+    timeinfo.tm_hour = 0;   timeinfo.tm_min = 0; timeinfo.tm_sec = 0;
+    timeinfo.tm_year = (2001 - 1900); timeinfo.tm_mon = 0; timeinfo.tm_mday = 1;
+    set_time(mktime(&timeinfo));
+    
+    // declare usbcomms
+    usbcomms = new UsbComms(mytimer);
+    
+    // declare sd handler
+    sdhandler = new SdHandler(mytimer);
+
+#ifdef ENABLE_GPRS_TESTING
+    gprs = new GprsHandler(mytimer, usbcomms);
+    measure = new MeasurementHandler(sdhandler, usbcomms, gprs, mytimer);
+#else
+    measure = new MeasurementHandler(sdhandler, usbcomms, mytimer);
+#endif
+
+    // declare grove
+    grove = new GroveDht22(measure, mytimer);
+
+    // put the handlers in an array for easy reference
+#ifdef ENABLE_GPRS_TESTING
+    AbstractHandler* handlers[] = {grove, usbcomms, sdhandler, measure, gprs};
+#else
+    AbstractHandler* handlers[] = {grove, usbcomms, measure, sdhandler};
+#endif
+
+    // send startup message to terminal
+    usbcomms->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, (char*)PROGRAM_TITLE);
+    usbcomms->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, (char*)PROGRAM_INFO);
+    usbcomms->setRequest(UsbComms::usbreq_PrintToTerminalTimestamp, (char*)"\r\n******************\r\n");
+
+    // flush output
+    fflush(stdout); 
+
+    
+    /* Pulse LED1 again to signify start up was successful */
+    myled1 = 1;
+    wait(0.2);
+    myled1 = 0;
+    wait(0.2);
+    myled1 = 1;
+    wait(0.2);
+    myled1 = 0;
+    wait(1);
+    myled1 = 1;
+    wait(0.2);
+    myled1 = 0;
+    wait(0.2);
+    myled1 = 1;
+    wait(0.2);
+    myled1 = 0;
+    wait(1);
+
+    
+    while(1) 
+    {
+        // perform run functions for all handlers, one after the other
+        for (int i = 0; i < NUM_HANDLERS; i++) {
+            handlers[i]->run();
+        }
+    }   // while
+
+    for (int i = 0; i < NUM_HANDLERS; i++) {
+        delete handlers[i];
+    }
+}   // main
+
+
+

diff -r 000000000000 -r 2df78a4443cd mbed.bld
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/4f6c30876dfa
\ No newline at end of file

diff -r 000000000000 -r 2df78a4443cd readme.md
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/readme.md	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,59 @@
+This project is written for the Arch GPRS V2.
+
+It aims to provide a convenient method of alerting a user of humidity. However, the grove DHT22
+sensor could easily be replaced with another Grove sensor with small changes to the code.
+
+Directories:
+ * DHT 
+	- for accessing the grove
+ * DS_1337 
+	- interface to the real time clock (which is a separate chip, i.e. not part of the micro)
+ * mbed 
+	- all mbed libraries
+ * SDFileSystem 
+	- for accessing the SD card. You need to be careful to import the right one (link to my blog)
+ * USBDevice 
+	- interface to serial comms over USB (talk to it from a PC)
+ * Handlers 
+	- this is where almost all of my code lives
+
+Handlers
+The handlers have the same structure (although they do not inherit from a common base class, but they should). They have a run function, which is a state machine called from the main while loop in main.cpp. This will run continuous routines such as polling and checking if a request has been raised.
+
+A request might be raised through a common request interface that passes an enum. However this might have to be more specific. Either way, the request is then handled in the state machine.
+
+GroveDht22
+ * Takes a measurement from the DHT22 hardware at a set interval
+ * On success, sends to measurement handler
+
+SdHandler
+ * Initialises and polls the SD card, checks for errors, etc
+ * Receives requests for writing a system message to the log, or writing a measurement to CSV
+
+UsbComms
+ * Checks to see if there is a connection to a PC
+ * Receives requests to send messages to PC
+ * Diverts incoming messages from PC to appropriate handlers
+
+MeasurementHandler
+ * GroveDht22 sends a measurement to this and it decides what to do with it
+ * Stores values for schedules, thresholds, last measurements
+ * Decides if a new measurement should be sent over SMS, SD
+ * Receives a request for last measurement, state, etc, from either UsbComms or SmsHandler
+
+GprsHandler (WIP)
+ * Checks to see if there are any incoming messages, directs them appropriately
+ * Gets requests from other handlers to send an SMS
+ 
+ 
+ 
+ 
+To do:
+	* Complete basic GprsHandler
+    * Set a threshold for humidity (hardcoded to start with) and send messages at this threshold
+    * Avoid sending more than x messages per y time (so don't get bombarded with messages)
+    * Send messages to a list of numbers, not just one
+    * Send messages on a schedule, e.g. send current humidity and temp once a day, so user knows it's OK
+    * Make the above three points configurable over USB (threshold, time off, list of numbers, schedule)
+    * Respond to certain messages, over SMS, to configure and make status known.
+    * Make a base class for handlers to inherit from, so that interface stays consistent

diff -r 000000000000 -r 2df78a4443cd rtc.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rtc.cpp	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,60 @@
+#include "rtc.h"
+#include "DS1337.h"
+
+// declare reference to interface to the hardware real time clock
+extern DS1337* RTC_DS1337;
+
+// RTC enabled flag
+static int _rtcEnabled;
+
+time_t my_rtc_read()
+{
+    time_t  retval = 0;     // time since start of epoch
+    tm      _time_tm;
+
+    RTC_DS1337->readTime();
+
+    // extract values from RTC to tm struct
+    _time_tm.tm_year = ((int)RTC_DS1337->getYears()) - 1900;       // struct tm stores (year - 1900)
+    _time_tm.tm_mon  = (int)RTC_DS1337->getMonths() - 1;         // struct tm stores months 0 - 11, DS1337 stores 1-12
+    _time_tm.tm_mday = (int)RTC_DS1337->getDays();
+    _time_tm.tm_hour = (int)RTC_DS1337->getHours();
+    _time_tm.tm_min  = (int)RTC_DS1337->getMinutes();
+    _time_tm.tm_sec  = (int)RTC_DS1337->getSeconds();
+
+    // convert to time_t    
+    retval = mktime(&_time_tm);
+    if (retval == (time_t) -1)
+        return (time_t)1;               // error
+    else
+        return retval;
+}
+
+
+//https://developer.mbed.org/teams/Seeed/code/Seeed_Arch_GPRS_V2_RTC_HelloWorld/file/6db7dfbab0f1/main.cpp
+void my_rtc_write(time_t _time)
+{
+    // extract time_t to time info struct
+    tm * timeinfo = localtime(&_time);
+
+    RTC_DS1337->setSeconds   (timeinfo->tm_sec);
+    RTC_DS1337->setMinutes   (timeinfo->tm_min);
+    RTC_DS1337->setHours     (timeinfo->tm_hour);
+    RTC_DS1337->setDays      (timeinfo->tm_mday);           // day of month
+    RTC_DS1337->setDayOfWeek (timeinfo->tm_wday);
+    RTC_DS1337->setMonths    (timeinfo->tm_mon + 1);        // struct tm stores months 0 - 11, DS1337 stores 1-12
+    RTC_DS1337->setYears     (timeinfo->tm_year + 1900);    // struct tm subtracts 1900 from year
+
+    RTC_DS1337->setTime();
+}
+
+void my_rtc_init()
+{
+    RTC_DS1337->start();
+    _rtcEnabled = 1;
+}
+
+int my_rtc_enabled()
+{
+    return _rtcEnabled;
+}

diff -r 000000000000 -r 2df78a4443cd rtc.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rtc.h	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,50 @@
+#ifndef __RTC_H__
+#define __RTC_H__
+
+#include "mbed.h"
+
+//! The functions needed to configure time in the micro, used in \sa attach_rtc, using the on board DS_1337
+/*!
+  As there is no on-chip RTC, connecting the time functionality to the DS_1337 enables more convenient use of time
+
+  The function which is called to configure is as such:
+  void attach_rtc(time_t (*read_rtc)(void), void (*write_rtc)(time_t), void (*init_rtc)(void), int (*isenabled_rtc)(void))
+
+ read_rtc is assigned \sa my_rtc_read
+
+ write_rtc is assigned \sa my_rtc_write
+
+ init_rtc is assigned \sa my_rtc_init
+
+ isenabled_rtc is assigned \sa my_rtc_enabled
+ */
+
+
+/*!
+ * \brief my_rtc_read Interfaces to the on board RTC DS1337 and converts read values to time_t
+ * \return the value read from the on board RTC converted to system struct time_t
+ */
+time_t my_rtc_read();
+
+
+/*!
+ * \brief my_rtc_write Interfaces to the on board RTC DS1337 and converts and writes the time given as time_t
+ * \param _time is the time in system time_t format which will be written to DS1337
+ */
+void my_rtc_write(time_t _time);
+
+
+/*!
+ * \brief my_rtc_init Initialises the RTC DS1337
+ */
+void my_rtc_init();
+
+
+/*!
+ * \brief my_rtc_enabled Checks if RTC DS1337 is enabled
+ * \return 1 if enabled, 0 if not enabled (i.e. \sa my_rtc_init never called)
+ */
+int my_rtc_enabled();
+
+
+#endif // __RTC_H__

diff -r 000000000000 -r 2df78a4443cd timers.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/timers.cpp	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,74 @@
+#include "timers.h"
+
+MyTimers::MyTimers()
+{
+    // initialise timers
+    groveMeasureTimer = 0;
+    gprsPowerTimer    = 0;
+    gprsRxTxTimer     = 0;
+    sdWaitErrorTimer  = 0;
+    measFlashTimer    = 0;
+
+    m_tick = new Ticker();
+    // configure the ticker object to run every 1ms, and to call \sa run when it does so.
+    m_tick->attach(this, &MyTimers::run, 0.001);
+}
+
+MyTimers::~MyTimers()
+{
+    delete m_tick;
+}
+
+void MyTimers::run()
+{
+    // decrement each timer in the class
+    if (groveMeasureTimer) groveMeasureTimer--;
+    if (gprsPowerTimer   ) gprsPowerTimer--;
+    if (gprsRxTxTimer    ) gprsRxTxTimer--;
+    if (sdWaitErrorTimer ) sdWaitErrorTimer--;
+    if (measFlashTimer   ) measFlashTimer--;
+}
+
+
+void MyTimers::SetTimer(eTimerType timertype, unsigned long time_ms)
+{
+    // see which timer we have to set, and set it
+    switch(timertype)
+    {
+    case tmr_GroveMeasure:
+        groveMeasureTimer = time_ms;
+        break;
+    case tmr_GprsPower:
+        gprsPowerTimer = time_ms;
+        break;
+    case tmr_GprsRxTx:
+        gprsRxTxTimer = time_ms;
+        break;
+    case tmr_SdWaitError:
+        sdWaitErrorTimer = time_ms;
+        break;
+    case tmr_MeasFlash:
+        measFlashTimer = time_ms;
+        break;
+    }
+}
+
+unsigned long MyTimers::GetTimer(eTimerType timertype)
+{
+    // see which timer we have to get, and return it.
+    switch(timertype)
+    {
+    case tmr_GroveMeasure:
+        return groveMeasureTimer;
+    case tmr_GprsPower:
+        return gprsPowerTimer;
+    case tmr_GprsRxTx:
+        return gprsRxTxTimer;
+    case tmr_SdWaitError:
+        return sdWaitErrorTimer;
+    case tmr_MeasFlash:
+        return measFlashTimer;
+    }
+    return 0;
+}
+

diff -r 000000000000 -r 2df78a4443cd timers.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/timers.h	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,57 @@
+#ifndef __TIMERS_H__
+#define __TIMERS_H__
+
+#include "mbed.h"
+
+/*!
+ * \brief The MyTimers class creates a Ticker and decrements a collection of unsigned longs that act as timers across the program
+ *
+ *  \sa eTimerType is used to link external callers with a collection of unsigned longs which are decremented
+ *  each ms by \sa run().
+ *  This acts as a collection of timers.
+ *  This collection can be set by \sa SetTimer and retrieved by \sa GetTimer.
+ */
+class MyTimers
+{
+public:
+    MyTimers();
+    ~MyTimers();
+
+    ///< eTimerType identifies each of the timers in program, and is used to set and get a timer
+    typedef enum
+    {
+        tmr_GroveMeasure,       ///< Used in GroveDht22 handler
+        tmr_GprsPower,          ///< Used to power the SIM900 on and off
+        tmr_GprsRxTx,           ///< Timeout waiting for a response from the SIM900 over the serial line
+        tmr_SdWaitError,        ///< Sd card has hit an error, wait before retrying
+        tmr_MeasFlash           ///< Flash once every 2 seconds for heartbeat
+    } eTimerType;
+
+    //! run is called each time Ticker fires, which is every 1ms, and decrements all timers if necessary
+    void run();
+
+    /*!
+     * \brief SetTimer sets the value of the timer
+     * \param timertype identifies the timer whose value we want to set
+     * \param time_ms is the value the timer will be set to, to start counting down from, in ms
+     */
+    void SetTimer(eTimerType timertype, unsigned long time_ms);
+
+    /*!
+     * \brief GetTimer gets the value of a timer
+     * \param timertype identifies the timer whose value we want to get
+     * \return the value of the timer
+     */
+    unsigned long GetTimer(eTimerType timertype);
+
+private:
+    unsigned long groveMeasureTimer;    ///< current value of timer for \sa tmr_GroveMeasure
+    unsigned long gprsPowerTimer;       ///< current value of timer for \sa tmr_GprsPower
+    unsigned long gprsRxTxTimer;        ///< current value of timer for \sa tmr_GprsRxTx
+    unsigned long sdWaitErrorTimer;     ///< current value of timer for \sa tmr_SdWaitError
+    unsigned long measFlashTimer;       ///< current value of timer for \sa tmr_MeasFlash
+
+    Ticker *m_tick;        ///< Used to call \a run a function periodically
+};
+
+#endif