Revision 2:6bfef0839102, committed 2014-11-07

Comitter:

Bobty

Date:

Fri Nov 07 16:09:15 2014 +0000

Parent:

1:518f39df3485

Child:

3:9f00be404f8f

Commit message:

Working - detects between pulse time and counts total pulses

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PulsePin.cpp	Fri Nov 07 16:09:15 2014 +0000
@@ -0,0 +1,53 @@
+// Handles a pin that has a slow pulse applied
+// Written for a gas meter monitor
+
+#include "PulsePin.h"
+
+PulsePin::PulsePin(DigitalIn& pin, bool risingEdge, int waitForPinStabilisationMs) :
+    _pin(pin)
+{
+    _risingEdge = risingEdge;
+    _waitForPinStabilisationMs = waitForPinStabilisationMs;
+    _pinTimer.start();
+    _curPinState = _pin;
+    _lastStableTimeMs = _pinTimer.read_ms();
+    _firstEdgeDetected = false;
+    _timeBetweenEdgesMs = 0;
+}
+
+bool PulsePin::Service()
+{
+    // Check time since last edge - looking for stability
+    int timeNowMs = _pinTimer.read_ms();
+    if (timeNowMs < _lastStableTimeMs + _waitForPinStabilisationMs)
+        return false;
+
+    // Check for a change of state
+    bool pinState = _pin;
+    if (pinState == _curPinState)
+        return false;
+        
+    _curPinState = pinState;
+    _lastStableTimeMs = timeNowMs;
+    
+    // Check if this is the direction of edge we're looking for
+    if (pinState != _risingEdge)
+        return false;
+        
+    // Reset the timer to avoid wrap around problems
+    bool firstEdgeDetected = _firstEdgeDetected;
+    _pinTimer.reset();
+    _firstEdgeDetected = true;
+    _lastStableTimeMs = 0;
+    
+    // Check if this should be returned
+    if (!firstEdgeDetected)
+        return false;
+    _timeBetweenEdgesMs = timeNowMs;
+    return true;
+}
+
+int PulsePin::GetLastCycleTimeMs()
+{
+    return _timeBetweenEdgesMs;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PulsePin.h	Fri Nov 07 16:09:15 2014 +0000
@@ -0,0 +1,24 @@
+#ifndef __PULSEPIN__H
+#define __PULSEPIN__H
+#include "mbed.h"
+
+class PulsePin
+{
+    public:
+        PulsePin(DigitalIn& pin, bool risingEdge, int pinStableTimeMs);
+        bool Service();
+        int GetLastCycleTimeMs();
+    
+    private:
+        DigitalIn& _pin;
+        Timer _pinTimer;
+        bool _curPinState;
+        bool _firstEdgeDetected;
+        int _lastStableTimeMs;
+        int _waitForPinStabilisationMs;
+        bool _risingEdge;
+        int _timeBetweenEdgesMs;
+};
+
+
+#endif
\ No newline at end of file

--- a/main.cpp	Fri Nov 07 14:44:23 2014 +0000
+++ b/main.cpp	Fri Nov 07 16:09:15 2014 +0000
@@ -1,11 +1,12 @@
 #include "mbed.h"
 #include "EthernetInterface.h"
+#include "PulsePin.h"
 
 DigitalIn gpPin(p21);
+PulsePin pulsePin(gpPin, false, 200);
 DigitalOut led(LED1);
 
 const int BROADCAST_PORT = 42853; // Arbitrarily chosen port number
-const int NUM_GASPULSE_VALS_IN_PACKET = 10;
 Serial pc(USBTX, USBRX);
 
 int main()
@@ -22,12 +23,9 @@
     Timer connectRetryTimer;
     connectRetryTimer.start();
     bool isConnected = false;
-
-    // Gas Meter Pulse sample timer
-    Timer gasPulseTimer;
-    gasPulseTimer.start();
-    int gasPulseCount = 0;
-    bool gasPulseVals[NUM_GASPULSE_VALS_IN_PACKET];
+    
+    // Count of gas pulses
+    int gasCount = 0;
     
     // Forever    
     while (true)
@@ -54,41 +52,30 @@
         }
         else
         {
-            if (gasPulseTimer.read_ms() > 1000)
+            led = gpPin;
+            // Check for an edge
+            bool edgeDetected = pulsePin.Service();
+            if (edgeDetected)
             {
-                gasPulseTimer.reset();
-                
-                // Read from Gas Pulse pin
-                gasPulseVals[gasPulseCount++] = gpPin;
-                led = gpPin;
-                if (gasPulseCount >= NUM_GASPULSE_VALS_IN_PACKET)
+                gasCount++;
+                char outBuf[200];
+                sprintf(outBuf, "[{\"n\":\"gasCount\",\"v\":%d},{\"n\":\"gasInterPulse\",\"v\":%d,\"u\":\"ms\"}]", 
+                                    gasCount, pulsePin.GetLastCycleTimeMs());
+                int bytesToSend = strlen(outBuf);
+                int rslt = sendSocket.sendTo(broadcast, outBuf, bytesToSend);
+                if (rslt == bytesToSend)
                 {
-                    gasPulseCount = 0;
-                    
-                    // Send the packet
-                    char outBuf[] = "{\"gaspulseval\":[0,0,0,0,0,0,0,0,0,0]}\n";
-                    char* pOutBuf = strchr(outBuf, '[') + 1;
-                    for (int i = 0; i < NUM_GASPULSE_VALS_IN_PACKET; i++)
-                    {
-                        *pOutBuf = gasPulseVals[i] ? '1' : '0';
-                        pOutBuf+=2;
-                    }
-                    int bytesToSend = sizeof(outBuf) - 2;
-                    int rslt = sendSocket.sendTo(broadcast, outBuf, bytesToSend);
-                    if (rslt == bytesToSend)
-                    {
-                        printf("Sent ok %s", outBuf);
-                    }
-                    else if (rslt == -1)
-                    {
-                        printf("Failed to send %s", outBuf);
-                        isConnected = false;
-                    }
-                    else
-                    {
-                        printf("Didn't send all of %s", outBuf);
-                        isConnected = false;
-                    }
+                    printf("Sent ok %s\n", outBuf);
+                }
+                else if (rslt == -1)
+                {
+                    printf("Failed to send %s\n", outBuf);
+                    isConnected = false;
+                }
+                else
+                {
+                    printf("Didn't send all of %s\n", outBuf);
+                    isConnected = false;
                 }
             }