added humi project in its current state. PID code does not work all that well currently.

humi/humi.ino

@@ -0,0 +1,287 @@
+// Device ID (grafana label)
+#define DEV_ID "humi"
+
+// ESP32 with Wifi
+#define DEVICE "ESP32"
+#include <WiFiMulti.h>
+WiFiMulti wifiMulti;
+#define WIFI_SSID "cazicthule2"
+#define WIFI_PASSWORD "kalamazoomi"
+
+// InfluxDB for grafana
+#include <InfluxDbClient.h>
+#define INFLUXDB_URL "http://192.168.1.6:8086"
+#define INFLUXDB_DB_NAME "ifdb"
+InfluxDBClient client(INFLUXDB_URL, INFLUXDB_DB_NAME);
+Point sensor(DEV_ID);
+
+// BME280 - TPH Temperature Pressure Humidity
+#include <Wire.h>
+#include <Adafruit_Sensor.h>
+#include <Adafruit_BME280.h>
+Adafruit_BME280 bme;
+
+const int HUMID_PIN_A = 16; // Mosfet A for ultrasonic himidifier
+const int HUMID_PIN_B = 23; // Mosfet B (unused for now)
+
+const int PID_PIN_KP = 33; //orange
+const int PID_PIN_KI = 32; //brown
+const int PID_PIN_KD = 34; //green\
+
+int potKp;
+int potKi;
+int potKd;
+
+const float Kp_Range = 2;
+const float Ki_Range = 0.2;
+const float Kd_Range = 2;
+
+// TODO add buttons to control these targets
+int VPD_mode = 1; // VPD -> 1; RH -> 0
+float VPD_target = 0.9; // Vapor Pressure Deficit target
+float RH_target = 65; // Relative Humidity target
+float setpoint;
+
+float temp_meas=18;
+float humid_meas=50;
+
+// used to revert outlandish measurements
+float humid_sane=humid_meas;
+float temp_sane=temp_meas;
+
+float Psat(float T){
+  // Calculate the Saturation Vapor Pressure using Arden Buck equation
+  // Psat = 0.61121 exp( (18.678 - T/234.5) * (T/(257.14+T)) )
+  return 0.61121 * pow(2.7182818284, (18.678 - T/234.5) * (T/(257.14+T)));
+}
+
+float VPD(float T, float RH){
+  // Calculate the Vapor Pressure Deficit in kPa
+  return Psat(T) * (1-RH/100.);
+}
+
+float RH(float VPDtarget, float T){
+  // Compute the required %RH to hit VPD_target
+  return 100. * ( 1 - VPDtarget/Psat(T) );
+}
+
+double readPot(int pin){
+  double pot_val;
+  double mag = 0.5;
+  pot_val = (double)analogRead(pin);
+  if(pot_val<1000) {
+    mag=0.0;
+  }
+  else{
+    if (pot_val > 3000){
+      mag=1.0;
+    }
+    else{
+      mag = (pot_val-1000.)/(3000.-1000.);
+    }
+  }
+  return(mag);
+}
+
+
+
+// PID Controller
+#include <PID_v1.h>
+//Declare PID Variables
+double PID_Setpoint, PID_Input, PID_Output;
+unsigned long PID_now;
+double PID_Kp=0.05, PID_Ki=5, PID_Kd=0;
+
+//Specify the links and initial tuning parameters
+PID myPID(&PID_Input, &PID_Output, &PID_Setpoint, PID_Kp, PID_Ki, PID_Kd, P_ON_M, DIRECT);
+
+// PID timer for interval between turning device on/off 10000=10seconds
+int PID_WindowSize = 10000;
+
+int PID_RESTART(){
+  float out=PID_Output;
+  myPID.SetMode(AUTOMATIC);
+  myPID.SetOutputLimits(0.0, 1.0);  // Forces minimum up to 0.0
+  myPID.SetOutputLimits(-1.0, 0.0);  // Forces maximum down to 0.0
+  myPID.SetOutputLimits(1, PID_WindowSize-1); // reset the output range
+  if (0<out && out<PID_WindowSize){
+    PID_Output=out;
+    return(1);
+  }
+  else{
+    PID_Output=0.25*PID_WindowSize;
+    return(0);
+  }
+}
+
+
+
+void setup() {
+
+  pinMode(HUMID_PIN_A, OUTPUT);
+  pinMode(HUMID_PIN_B, OUTPUT);
+
+  pinMode(PID_PIN_KP, INPUT);
+  pinMode(PID_PIN_KI, INPUT);
+  pinMode(PID_PIN_KD, INPUT);
+
+  Serial.begin(115200);
+
+  // BME setup
+  if (!bme.begin(0x76)) {
+    Serial.println("Could not find a valid BME280 sensor, check wiring!");
+    while (1);
+  }
+
+  // PID setup
+  //initialize the variables we're linked to (Input and Setpoint)
+  PID_Setpoint = RH(VPD_target,bme.readTemperature());
+  //tell the PID to range between 0 and the full window size
+  myPID.SetOutputLimits(1, PID_WindowSize-1);
+  //turn the PID on
+  myPID.SetMode(AUTOMATIC);
+  PID_Output=0.25*(PID_WindowSize);
+  
+  // WiFi setup
+  Serial.println("Connecting to WiFi");
+  WiFi.mode(WIFI_STA);
+  wifiMulti.addAP(WIFI_SSID, WIFI_PASSWORD);
+  while (wifiMulti.run() != WL_CONNECTED) {
+    Serial.print(".");
+    delay(500);
+  }
+  Serial.println();
+  // Check server connection
+  if (client.validateConnection()) {
+    Serial.print("Connected to InfluxDB: ");
+    Serial.println(client.getServerUrl());
+  } else {
+    Serial.print("InfluxDB connection failed: ");
+    Serial.println(client.getLastErrorMessage());
+  }
+}
+
+void loop() {
+
+// If measured RH is too low
+
+  PID_now = millis();
+
+  // This loop runs every 10seconds (windowsize)
+  //loop for device on time (deltat < windowsize) 10000 = 10seconds between power cycles
+  while ( millis() - PID_now < PID_WindowSize ){
+    // Measure Temperature and Humidity (TODO do some error checking)
+    temp_meas = bme.readTemperature(); // Celcius
+    
+    humid_meas = bme.readHumidity(); // Relative Humidity (%)
+  
+    // Calculate the setpoint RH from the target VPD and current temperature
+    setpoint=(RH(VPD_target,temp_meas)); 
+
+    if (humid_meas<0.9*setpoint){
+      //reset PID (only in automatic mode)
+      //myPID.SetOutputLimits(0.0, 1.0);  // Forces minimum up to 0.0
+      //myPID.SetOutputLimits(-1.0, 0.0);  // Forces maximum down to 0.0
+      //myPID.SetOutputLimits(1, PID_WindowSize-1);
+      // turn humi full on
+      PID_Output=PID_Output+PID_WindowSize*0.01;
+      myPID.SetMode(MANUAL);
+      digitalWrite(HUMID_PIN_A, HIGH);
+
+      
+      // wait windowsize time to try again
+      delay(PID_WindowSize);
+    }
+    else if (humid_meas>1.1*setpoint) {
+      //reset PID (only in automatic mode)
+      //myPID.SetOutputLimits(0.0, 1.0);  // Forces minimum up to 0.0
+      //myPID.SetOutputLimits(-1.0, 0.0);  // Forces maximum down to 0.0
+      //myPID.SetOutputLimits(1, PID_WindowSize-1);
+      // turn humi full off 
+      PID_Output=abs(PID_Output-PID_WindowSize*0.01);
+      myPID.SetMode(MANUAL);
+      digitalWrite(HUMID_PIN_A, LOW);
+
+      
+      // wait windowsize time to try again
+      delay(PID_WindowSize);
+    }
+    else{
+      // PID control
+      myPID.SetMode(AUTOMATIC);
+
+      //PID input: the current RH value
+      PID_Input = humid_meas;
+      //PID Setpoint: calculate the required RH to hit target VPD
+      PID_Setpoint = setpoint;
+
+      myPID.Compute();
+
+      //Serial.println(PID_WindowSize);
+      //Serial.println(PID_Output);  // duty cycle is PID_Output divided by PID_WindowSize
+      //Serial.println(PID_Setpoint);
+      //Serial.println(PID_Input);
+
+      // trigger off for cycle
+      if ( millis() - PID_now > PID_Output ){
+       digitalWrite(HUMID_PIN_A, LOW);
+      }
+      //trigger on for cycle
+      else{
+        digitalWrite(HUMID_PIN_A, HIGH);
+      }
+      delay(200);
+    }
+  }
+
+  //read PID from pots
+  PID_Kp= readPot(PID_PIN_KP)*Kp_Range+1.0;
+  PID_Ki= readPot(PID_PIN_KI)*Ki_Range;
+  PID_Kd= 2.0;
+
+ 
+  //print PID
+  Serial.print("  KP:");
+  Serial.print(PID_Kp);
+  Serial.print("  KI:");
+  Serial.print(PID_Ki);
+  Serial.print("  KD:");
+  Serial.println(PID_Kd);
+
+  // update PID
+  myPID.SetTunings(PID_Kp, PID_Ki, PID_Kd);
+
+  
+  // Write values and triggers into influxdb
+  sensor.clearFields();
+  sensor.addField("VPD",VPD(temp_meas,humid_meas));
+  sensor.addField("VPDtarget",VPD_target);
+  sensor.addField("Temperature",(temp_meas*9/5.) + 32.);
+  sensor.addField("Humidity",humid_meas);
+  sensor.addField("Humidity_target",RH(VPD_target,temp_meas));
+  sensor.addField("Duty",PID_Output/(float)PID_WindowSize);
+  sensor.addField("PID_Output",PID_Output);
+  sensor.addField("PID_Kp",PID_Kp);
+  sensor.addField("PID_Ki",PID_Ki);
+  sensor.addField("PID_Kd",PID_Kd);
+  
+  // Send fields to InfluxDB
+  Serial.print("Writing: ");
+  Serial.println(client.pointToLineProtocol(sensor));
+  // If no Wifi signal, try to reconnect it
+  if (wifiMulti.run() != WL_CONNECTED) {
+    Serial.println("Wifi connection lost");
+  }
+  
+  // Write point
+  if (!client.writePoint(sensor)) {
+    Serial.print("InfluxDB write failed: ");
+    Serial.println(client.getLastErrorMessage());
+  }
+
+  // modify window size to tune mister to 30% load
+  // need to collect the "average load" over a long period
+  // if mean(load) < 0.25 and variance is low ; PID_WindowSize increases by 10%
+  // if mean(load) > 0.60 and variance is low ; PID_WindowSize decreases by 10%
+  
+}