add voltage sensing

src/main.cpp

@@ -8,6 +8,16 @@
 
 //Upload config: platformio run --target uploadfs
 
+#define PIN_VBAT A0
+unsigned long vbat_calib1_adc=581; //adc value at vbat_calib_voltage (voltage at battery)
+float vbat_calib1_voltage=6.0; //voltage used for calibration
+
+unsigned long vbat_calib2_adc=782; //second calibration point (higher voltage)
+float vbat_calib2_voltage=8.0;
+
+int vbat_raw_filtered=-1; //-1 flags it as initialized
+bool vbatSent=false;
+
 #include <TM1637Display.h>
 
 #define TM1637_CLK D5
@@ -82,7 +92,8 @@ bool livesend=false; //if true, sends continuous data over mqtt
 void loopHandler();
 
 HomieNode scaleNode("weight", "Scale", "scale"); //paramters: topic, $name, $type
-HomieNode displayNode("display", "Scale", "scale"); //paramters: topic, $name, $type
+HomieNode displayNode("display", "Display", "scale"); //paramters: topic, $name, $type
+HomieNode hardwareNode("hardware", "Hardware", "scale"); //paramters: topic, $name, $type
 
 int sort_desc(const void *cmp1, const void *cmp2);
 float getFilteredWeight();
@@ -92,8 +103,10 @@ bool cmdHandler(const HomieRange& range, const String& value);
 bool displayNodeHandler(const HomieRange& range, const String& value);
 void powerOff();
 void displayNumber(float numberdisplay);
-
+float getVBat();
-
+void updateVBat();
+void sendVBat();
+float mapFloat(float x, float in_min, float in_max, float out_min, float out_max);
 
 void setup() {
   pinMode(PIN_SELFENABLE,OUTPUT);
@@ -114,7 +127,7 @@ void setup() {
   Homie_setBrand(FW_NAME);
   Homie.setLoopFunction(loopHandler);
 
-  scaleNode.advertise("cmd").settable(cmdHandler);  //function inputHandler gets called on new message on topic/input/set  
+  
   scaleNode.advertise("human");
   scaleNode.advertise("spread");
   scaleNode.advertise("raw");
@@ -122,6 +135,10 @@ void setup() {
 
   displayNode.advertise("segments").settable(displayNodeHandler);  
 
+  hardwareNode.advertise("cmd").settable(cmdHandler);  //function inputHandler gets called on new message on topic/input/set  
+  hardwareNode.advertise("vbat");
+  hardwareNode.advertise("vbatraw");
+
   Homie.setup();
 
 
@@ -148,12 +165,12 @@ void loop() {
 void loopHandler() {
   unsigned long loopmillis=millis();
  
-  
- 
   static unsigned long last_measure=0;
   if (loopmillis>last_measure+MEASURE_INTERVAL) {
     last_measure=loopmillis;
 
+    updateVBat(); //also update vbat reading
+
     //Serial.print("reading=");
     weight_current=0;
     if (scale.wait_ready_timeout(1000)) { //for non blocking mode      
@@ -163,7 +180,7 @@ void loopHandler() {
       weight_read[weight_read_pos]=weight_current; //one reading takes 91ms
     } else {
         Serial.println("HX711 not found.");
-        scaleNode.setProperty("cmd").send("HX711 not found"); //can be done in main loop
+        hardwareNode.setProperty("cmd").send("HX711 not found"); //can be done in main loop
     }
       
     weight_filtered=getFilteredWeight();
@@ -196,15 +213,30 @@ void loopHandler() {
 
     if (!weight_sent) {
       if (weight_max-weight_tare>MIN_WEIGHT_DIFFERENCE) {
+        if (Homie.getMqttClient().connected()) {
           sendWeight(weight_max-weight_tare);
+        }else{
+          Serial.println("Cannot send weight because mqtt not connected!");
+        }
         update_display=true;
       }
     }
+
+    
+    if (!vbatSent && loopmillis>10000) { //send voltage some time after turn on
+      if (Homie.getMqttClient().connected()) {
+        sendVBat();
+        vbatSent=true;
+      }else{
+        Serial.println("Cannot send vbat because mqtt not connected!");
+      }
+    }
+
   }
 
 
 
-  if (livesend && (millis()>last_mqtt_send+MQTT_SENDINTERVALL)) {
+  if (Homie.getMqttClient().connected() && livesend && (millis()>last_mqtt_send+MQTT_SENDINTERVALL)) {
     last_mqtt_send=millis();
 
     //float weight_filtered=getFilteredWeight();
@@ -315,10 +347,10 @@ bool cmdHandler(const HomieRange& range, const String& value) {
     if (scale.wait_ready_timeout(1000)) { //for non blocking mode
       scale.set_scale();
       scale.tare();
-      scaleNode.setProperty("cmd").send("tared");
+      hardwareNode.setProperty("cmd").send("tared");
     } else {
       Serial.println("HX711 not found.");
-      scaleNode.setProperty("cmd").send("HX711 not found");
+      hardwareNode.setProperty("cmd").send("HX711 not found");
     }
     
   }else if (value=="calibrate") { //get raw value. use "reset" first. then adc to get value for calibration to enter in SCALE_CALIBRATION
@@ -326,21 +358,23 @@ bool cmdHandler(const HomieRange& range, const String& value) {
       long _units=scale.get_units(10); //if set_scale was called with no parameter before, get_units has not decimals
       char charBuf[13];
       dtostrf(_units,2, 1, charBuf);
-      scaleNode.setProperty("cmd").send(charBuf);
+      hardwareNode.setProperty("cmd").send(charBuf);
     } else {
       Serial.println("HX711 not found.");
-      scaleNode.setProperty("cmd").send("HX711 not found");
+      hardwareNode.setProperty("cmd").send("HX711 not found");
     }
   }else if (value=="live") {
     livesend=!livesend;
     if (livesend) {
-      scaleNode.setProperty("cmd").send("live data enabled");
+      hardwareNode.setProperty("cmd").send("live data enabled");
     }else{
-      scaleNode.setProperty("cmd").send("live data disabled");
+      hardwareNode.setProperty("cmd").send("live data disabled");
     }
+  }else if (value=="vbat") {
+    sendVBat();
   }else if (value=="off") {
     powerOff();    
-    scaleNode.setProperty("cmd").send("shutting down");
+    hardwareNode.setProperty("cmd").send("shutting down");
   } else {
     Homie.getLogger() << "cmd not recognized" << endl;
     return false;  
@@ -460,3 +494,31 @@ void displayNumber(float numberdisplay) {
       
     }
 }
+
+float getVBat() { //get filtered vbat value
+  return mapFloat(vbat_raw_filtered,vbat_calib1_adc,vbat_calib2_adc, vbat_calib1_voltage,vbat_calib2_voltage); //2-point mapping  adc -> voltage;
+}
+
+void updateVBat() { //continuous update for filtering
+  float vbat_filter=0.95; //the closer to 1 the higher the filtering. 0 means no filtering
+  if (vbat_raw_filtered<0) {  //at first reading (vbat_raw_filtered is initialized with value <0)
+    vbat_filter=0; //use first reading with 100%
+  }
+  vbat_raw_filtered=vbat_raw_filtered*vbat_filter + analogRead(PIN_VBAT)*(1.0-vbat_filter);
+}
+
+void sendVBat() {
+  char charBuf[10];
+  dtostrf(vbat_raw_filtered,1, 0, charBuf);
+  hardwareNode.setProperty("vbatraw").send(charBuf); 
+  Serial.print("vbatraw="); Serial.println(vbat_raw_filtered);
+
+  dtostrf(getVBat(),4, 3, charBuf);
+  hardwareNode.setProperty("vbat").send(charBuf);   
+  Serial.print("vbat="); Serial.println(getVBat(),3);
+}
+
+float mapFloat(float x, float in_min, float in_max, float out_min, float out_max)
+{
+ return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
+}