Updates to fix connection issue on startup and added support for DHT sensors

Author: mkals

Arduino/arduino.py

@@ -108,6 +108,7 @@ def __init__(self, baud=9600, port=None, timeout=2, sr=None):
                     raise ValueError("Could not find port.")
             else:
                 sr = serial.Serial(port, baud, timeout=timeout)
+                sr.readline()
         sr.flush()
         self.sr = sr
         self.SoftwareSerial = SoftwareSerial(self)
@@ -126,7 +127,7 @@ def digitalWrite(self, pin, val):
            pin : digital pin number
            val : either "HIGH" or "LOW"
         """
-        if val == "LOW":
+        if val.upper() == "LOW":
             pin_ = -pin
         else:
             pin_ = pin
@@ -205,7 +206,7 @@ def pulseIn(self, pin, val):
         returns:
            duration : pulse length measurement
         """
-        if val == "LOW":
+        if val.upper() == "LOW":
             pin_ = -pin
         else:
             pin_ = pin
@@ -250,7 +251,7 @@ def pulseIn_set(self, pin, val, numTrials=5):
         pinMode(pin, INPUT);
         long duration = pulseIn(pin, HIGH);
         """
-        if val == "LOW":
+        if val.upper() == "LOW":
             pin_ = -pin
         else:
             pin_ = pin
@@ -410,6 +411,57 @@ def shiftIn(self, dataPin, clockPin, pinOrder):
             return int(rd)
 
 
+    def dht(self, pin, module = 0):
+        """
+        Read data from dht temperature and humidity sensors based on the
+        Adafruit DHT sensor library.
+        https://github.com/adafruit/DHT-sensor-library
+
+        Guide for using library:
+        https://learn.adafruit.com/dht/using-a-dhtxx-sensor
+
+        There are five sensors that work with this library:
+        - DHT 11: blue cage, less accurate
+        - DHT 12:
+        - DHT 21:
+        - DHT 22: white cage
+        - AM2301:
+        Input:
+            pin (int): pin for data
+            module (int):   0 = DHT 11 (default),
+                            1 = DHT 12,
+                            2 = DHT 21,
+                            3 = DHT 22,
+                            4 = AM2301
+        Output:
+            [float, float, float] in the format:
+            [ humidity in %,
+              temperature in celcius,
+              heat index in celcius ]
+        """
+        try:
+            if not (0 <= module <= 4):
+                print("unknown module, must be in range 0 to 4. Using 0 (DHT 11).")  # raise exception
+        except:
+            module = 0
+            print("module must be spesified using an integer. Using 0 (DHT 11).")
+
+        cmd_str = build_cmd_str("dht", (pin, module,))
+        try:
+            self.sr.write(str.encode(cmd_str))
+            self.sr.flush()
+        except:
+            pass
+        rd = self.sr.readline().decode("utf-8").replace("\r\n", "")
+        try:
+            strings = rd.split("&")
+            return [float(s) for s in strings]
+        except:
+            return None
+
+
+
+
 class Shrimp(Arduino):
 
     def __init__(self):
@@ -497,6 +549,7 @@ def read(self, pin):
             return None
 
 
+
 class SoftwareSerial(object):
 
     """

sketches/prototype/prototype.ino

@@ -2,6 +2,7 @@
 #include <Wire.h>
 #include <Servo.h>
 #include <EEPROM.h>
+#include <DHT.h>
 
 SoftwareSerial *sserial = NULL;
 Servo servos[8];
@@ -316,6 +317,49 @@ void EEPROMHandler(int mode, String data) {
     }
 }
 
+int dhtSensorPin = -1;
+DHT dhtSensor(dhtSensorPin, DHT11);
+
+void dht(String data) {
+  
+    String sdata[2];
+    split(sdata, 2, data, '%');
+    int dataPin = sdata[0].toInt();
+    int sensorNumber = sdata[1].toInt();
+    
+    int sensorType = DHT11; // assume DHT11 as default
+    if (sensorNumber == 1) {
+      sensorType = DHT12;
+    } else if (sensorNumber == 2) {
+      sensorType = DHT21;
+    } else if (sensorNumber == 2) {
+      sensorType = DHT22;
+    } else if (sensorNumber == 2) {
+      sensorType = AM2301;
+    }
+
+    // do not initialize new sensor if we are reading repeatedly from same sensor
+    if (dataPin != dhtSensorPin) {
+        dhtSensorPin = dataPin;
+        dhtSensor = DHT(dataPin, sensorType);
+        dhtSensor.begin();
+    }
+
+    // Reading temperature or humidity takes about 250 milliseconds!
+    // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
+    float h = dhtSensor.readHumidity();
+    // Read temperature as Celsius (the default)
+    float t = dhtSensor.readTemperature();
+    
+    if (isnan(h) || isnan(t)) {
+        Serial.println("0&0&0");
+        return;
+    }
+    
+    float hic = dhtSensor.computeHeatIndex(t, h, false);
+    Serial.println(String(h) + "&" + String(t) + "&" + String(hic));
+}
+
 void SerialParser(void) {
   char readChar[64];
   Serial.readBytesUntil(33,readChar,64);
@@ -399,16 +443,20 @@ void SerialParser(void) {
   }  
   else if (cmd == "sz") {  
       sizeEEPROM();
-  }  
+  }
+  else if (cmd == "dht") {
+      dht(data);
+  }
 }
 
 void setup()  {
-  Serial.begin(9600); 
+  Serial.begin(115200); 
     while (!Serial) {
-    ; // wait for serial port to connect. Needed for Leonardo only
-  }
+      ; // wait for serial port to connect. Needed for Leonardo only
+    }
+  Serial.println("connected");
 }
 
 void loop() {
-   SerialParser();
-   }
+  SerialParser();
+}