Trigger a reset if the pH goes below 7.0 (#229)

* Trigger a reset if the pH goes below 7.0 (so bubbler isn't on continually).

* format

* Avoid tests with pH below 7.0 since that uses an infinite loop to trigger the watchdog timer.

Author: James Foster

src/Devices/PHProbe.cpp

@@ -1,5 +1,7 @@
 #include "Devices/PHProbe.h"
 
+#include <avr/wdt.h>
+
 #include "Devices/Serial_TC.h"
 
 //  class instance variables
@@ -64,6 +66,14 @@ void PHProbe::serialEvent1() {
       if (isdigit(string[0])) {  // if the first character in the string is a digit
         // convert the string to a floating point number so it can be evaluated by the Arduino
         value = string.toFloat();
+        // we have seen situations where the CO2 bubbler stays on and drives the pH down
+        if (value < 7.0) {  // hang so as to trigger the watchdog timer reset
+          wdt_disable();
+          wdt_enable(WDTO_15MS);
+          serial("pH value dropped to %5.3f so trigger a reset!", value);
+          while (true) {
+          }
+        }
       } else if (string[0] == '?') {  // answer to a previous query
         serial("PHProbe serialEvent1: \"%s\"", string.c_str());
         if (string.length() > 7 && string.substring(0, 7) == "?SLOPE,") {

test/PHControlTest.cpp

@@ -33,8 +33,8 @@ void reset() {
   DateTime_TC january(2021, 1, 15, 1, 48, 24);
   january.setAsCurrent();
   controlSolenoid->enablePID(false);
-  controlSolenoid->setTargetPh(7.00);
-  setPhMeasurementTo(7.00);
+  controlSolenoid->setTargetPh(7.50);
+  setPhMeasurementTo(7.50);
   state->serialPort[0].dataOut = "";  // the history of data written
 }
 
@@ -82,31 +82,31 @@ unittest(bubblerTurnsOnAndOff) {
 unittest(afterTenSecondsButPhStillHigher) {
   assertEqual(TURN_SOLENOID_OFF, state->digitalPin[PH_CONTROL_PIN]);
   assertFalse(controlSolenoid->isOn());
-  controlSolenoid->setTargetPh(7.00);
-  setPhMeasurementTo(8.00);
+  controlSolenoid->setTargetPh(7.50);
+  setPhMeasurementTo(8.50);
   assertEqual(TURN_SOLENOID_ON, state->digitalPin[PH_CONTROL_PIN]);
   assertTrue(controlSolenoid->isOn());
   delay(8000);
-  setPhMeasurementTo(8.00);
+  setPhMeasurementTo(8.50);
   assertEqual(TURN_SOLENOID_ON, state->digitalPin[PH_CONTROL_PIN]);
   assertTrue(controlSolenoid->isOn());
   delay(2000);
-  setPhMeasurementTo(7.25);
+  setPhMeasurementTo(7.75);
   assertEqual(TURN_SOLENOID_ON, state->digitalPin[PH_CONTROL_PIN]);
   assertTrue(controlSolenoid->isOn());
 }
 
 unittest(afterTenSecondsAndPhIsLower) {
   assertEqual(TURN_SOLENOID_OFF, state->digitalPin[PH_CONTROL_PIN]);
   assertFalse(controlSolenoid->isOn());
-  assertEqual("pH 7.000   7.000", lc->getLines().at(0));
-  controlSolenoid->setTargetPh(7.00);
-  setPhMeasurementTo(8.00);
+  assertEqual("pH 7.500   7.500", lc->getLines().at(0));
+  controlSolenoid->setTargetPh(7.50);
+  setPhMeasurementTo(8.50);
   assertEqual(TURN_SOLENOID_ON, state->digitalPin[PH_CONTROL_PIN]);
   assertTrue(controlSolenoid->isOn());
   assertEqual("CO2 bubbler turned on after 7 ms\r\n", state->serialPort[0].dataOut);
   tc->loop();
-  assertEqual("pH 8.000 B 7.000", lc->getLines().at(0));
+  assertEqual("pH 8.500 B 7.500", lc->getLines().at(0));
   delay(8000);
   tc->loop();
   assertEqual(TURN_SOLENOID_ON, state->digitalPin[PH_CONTROL_PIN]);
@@ -118,7 +118,7 @@ unittest(afterTenSecondsAndPhIsLower) {
   assertEqual(TURN_SOLENOID_OFF, state->digitalPin[PH_CONTROL_PIN]);
   assertFalse(controlSolenoid->isOn());
   delay(1000);
-  setPhMeasurementTo(6.75);
+  setPhMeasurementTo(7.25);
   assertEqual(TURN_SOLENOID_OFF, state->digitalPin[PH_CONTROL_PIN]);
   assertFalse(controlSolenoid->isOn());
 }
@@ -132,21 +132,21 @@ unittest(beforeTenSecondsButPhIsLower) {
   assertEqual(TURN_SOLENOID_OFF, state->digitalPin[PH_CONTROL_PIN]);
   assertFalse(controlSolenoid->isOn());
   delay(1000);
-  controlSolenoid->setTargetPh(7.00);
-  setPhMeasurementTo(8.00);
+  controlSolenoid->setTargetPh(7.50);
+  setPhMeasurementTo(8.50);
   assertEqual(TURN_SOLENOID_ON, state->digitalPin[PH_CONTROL_PIN]);
   assertTrue(controlSolenoid->isOn());
   delay(7500);
-  setPhMeasurementTo(6.75);
+  setPhMeasurementTo(7.25);
   assertEqual(TURN_SOLENOID_OFF, state->digitalPin[PH_CONTROL_PIN]);
   assertFalse(controlSolenoid->isOn());
 }
 
 unittest(PhEvenWithTarget) {
   assertEqual(TURN_SOLENOID_OFF, state->digitalPin[PH_CONTROL_PIN]);
   assertFalse(controlSolenoid->isOn());
-  controlSolenoid->setTargetPh(7.00);
-  setPhMeasurementTo(7.00);
+  controlSolenoid->setTargetPh(7.50);
+  setPhMeasurementTo(7.50);
   assertEqual(TURN_SOLENOID_OFF, state->digitalPin[PH_CONTROL_PIN]);
   assertFalse(controlSolenoid->isOn());
 }
@@ -163,8 +163,8 @@ unittest(disableDuringCalibration) {
   // device is initially off and stays off due to calibration
   assertEqual(TURN_SOLENOID_OFF, state->digitalPin[PH_CONTROL_PIN]);
   assertFalse(controlSolenoid->isOn());
-  controlSolenoid->setTargetPh(7.00);
-  setPhMeasurementTo(8.00);
+  controlSolenoid->setTargetPh(7.50);
+  setPhMeasurementTo(8.50);
   assertEqual(TURN_SOLENOID_OFF, state->digitalPin[PH_CONTROL_PIN]);
   assertFalse(controlSolenoid->isOn());
 }