Change libraries used for mqtt and json parsing.

Not using strings for data any more.

boil_kettle/boil_kettle.ino

@@ -4,8 +4,8 @@
 #include <Ethernet.h>
 
 // Additoinal Libraries
-#include <ArduinoJson.h>
-#include <MQTT.h>
+#include <cJSON.h>
+#include <PubSubClient.h>
 #include <LiquidCrystal_I2C.h>
 #include <LiquidMenu.h> // LiquidMenu_config.h needs to be modified to use I2C.
 #include <MD_REncoder.h>
@@ -26,8 +26,10 @@ slowPWM boilPWM;
 MD_REncoder rotary = MD_REncoder(encoderDT, encoderCLK);
 LiquidCrystal_I2C lcd(0x27,20,4);
 
+void MessageReceived(char*, byte*, unsigned int);
+
 EthernetClient net;
-MQTTClient mqtt_client;
+PubSubClient mqtt_client(MQTT_BROKER, 1883, MessageReceived, net);
 
 unsigned long lastRun = 0;
 
@@ -87,7 +89,7 @@ void setup() {
 
   // if you get a connection, report back via serial:
   if (Ethernet.linkStatus() == LinkON) {
-    SetupMQTT(MQTT_BROKER);
+    ConnectMQTT();
   } else {
     // if you didn't get a connection to the server:
     Serial.println("connection failed");

boil_kettle/mqtt.ino

@@ -1,72 +1,58 @@
 void ConnectMQTT() {
   static const char *password = MQTT_PASSWORD;
   static const char *user = MQTT_USER;
-  Serial.println("connecting MQTT...");
   while (!mqtt_client.connect("brewhouse", user, password)) {
     Serial.print(".");
     delay(1000);
   }
 
-  Serial.println("\nconnected!");
-  mqtt_client.subscribe("brewery/setpoint/bk");
+  char topic[30];
+  strcpy(topic,TOPIC_ROOT);
+  strcat(topic,BOIL_SETPOINT_TOPIC);
+  mqtt_client.subscribe(topic);
 }
 
-void MessageReceived(String &topic, String &payload) {
-  Serial.println("incoming: " + topic + " - " + payload);
-
-  /** JSON Parser Setup */
-  StaticJsonDocument<200> doc;
-
-  // Deserialize the JSON document
-  DeserializationError error = deserializeJson(doc, payload);
-
-  // Test if parsing succeeds.
-  if (error) {
-    Serial.print(F("deserializeJson() failed: "));
-    Serial.println(error.f_str());
-    return;
-  }
+void MessageReceived(char* topic, byte* payload, unsigned int length) {
   char buf[30];
-  strcpy(buf,TOPIC_PREFIX);
+  strcpy(buf,TOPIC_ROOT);
   strcat(buf,BOIL_SETPOINT_TOPIC);
-  if (topic == buf) {
+
+  char msg[length+1];
+
+  for (int i=0;i<length;i++) {
+    msg[i] = (char)payload[i];
+  }
+  msg[length] = 0;
+  
+  if (strcmp(topic, buf) == 0) {
+    cJSON *monitor_json = cJSON_Parse(msg);
+    const cJSON *name = NULL;
+    const cJSON *setting = NULL;
+    const cJSON *unit = NULL;
+
     // Update PWM setpoint.
-    String name = doc["entity"];
-    String setting = doc["setpoint"];
-
-    KettleDuty = setting.toInt();
-    String unit = doc["units"];
-
-    Serial.println("Updating setpoint for " + name + " to " + setting + " " + unit);
+    setting = cJSON_GetObjectItemCaseSensitive(monitor_json, "setpoint");
+    KettleDuty = setting->valueint;
   }
 }
 
-void SetupMQTT(const char *broker) {
-  // Note: Local domain names (e.g. "Computer.local" on OSX) are not supported
-  // by Arduino. You need to set the IP address directly.
-  Serial.println("Setup MQTT client.");
-  mqtt_client.begin(broker, net);
-  mqtt_client.onMessage(MessageReceived);
-
-  ConnectMQTT();
-}
-
 static void SendSensorData() {
-  Serial.println("Sending data...");
 
-  // NOTE: max message length is 250 bytes.
-  StaticJsonDocument<200> doc;
+  char *string = NULL;
+  cJSON *entity = NULL;
+  cJSON *setpoint = NULL;
+  cJSON *units = NULL;
 
-  doc["entity"] = "boil_kettle";
-  doc["setpoint"] = KettleDuty;
-  doc["units"] = "%";
+  cJSON *monitor = cJSON_CreateObject();
+  cJSON_AddStringToObject(monitor, "entity", "boil_kettle");
+  cJSON_AddNumberToObject(monitor, "setpoint", KettleDuty);
+  cJSON_AddStringToObject(monitor, "units", "%");
+  char *msg = cJSON_Print(monitor);
 
-  String jstr;
-  serializeJson(doc, jstr);
+  char topic[30];
+  strcpy(topic,TOPIC_ROOT);
+  strcat(topic,BOIL_ACTUAL_TOPIC);
 
-  String topic = TOPIC_PREFIX;
-  topic += "sensor/boil_kettle";
-
-  mqtt_client.publish(topic, jstr);
+  mqtt_client.publish(topic, msg);
 
 }