Implement initial firmware version of envisens

envisens/atmega_fw/atmega_fw.ino

@@ -0,0 +1,62 @@
+/* Macrocell environmental sensor project EnviSens
+ *  
+ *  This firmware provides features to use an ATMEGA µC as an environmental sensor provider.
+ *  Currently supported sensors:
+ *   - digital pin D2: DHT22 temperature and humidity sensor 
+ *   - analog  pin A0: MQ135 gas and air quality sensor
+ *  
+ *  (C) 2019 Macrocell - Environmental Sensing Solutions (MESS)
+ *   proudly presented by Macrocell - FPGA Innovators
+ */
+
+#include <Wire.h>
+#include "DHT.h"
+#include "configuration.h"
+
+#define MQ135_PIN A0
+#define DHT_PIN 2     // Digital pin connected to the DHT sensor
+#define DHT_TYPE DHT22   // DHT 22  (AM2302), AM2321
+DHT dht(DHT_PIN, DHT_TYPE);
+
+int sensorValue;
+long last_sample = 0;
+ 
+void setup() {
+  Serial.begin(SERIAL_BAUDRATE); 
+  pinMode(MQ135_PIN, INPUT);
+  pinMode(LED_BUILTIN, OUTPUT); 
+  digitalWrite(LED_BUILTIN, LOW);
+  dht.begin();
+}
+
+void loop() {
+  long now = millis();
+  if (now - last_sample > OPERATION_PERIOD / 2) {
+    if (OPERATION_BLINK_EN) {digitalWrite(LED_BUILTIN, LOW);}
+  }
+  if (now - last_sample > OPERATION_PERIOD) {
+    last_sample = now;
+    if (OPERATION_BLINK_EN) {digitalWrite(LED_BUILTIN, HIGH);}
+
+    float h = dht.readHumidity();
+    float t = dht.readTemperature();
+  
+    if (isnan(h) || isnan(t)) {
+      Serial.println(F("Failed to read from DHT sensor!"));
+    } else {
+      float hi = dht.computeHeatIndex(t, h, false);
+      Serial.print(F("Humidity: "));
+      Serial.print(h);
+      Serial.print(F("%  Temperature: "));
+      Serial.print(t);
+      Serial.print(F("°C  Heat index: "));
+      Serial.print(hi);
+      Serial.println(F("°C "));
+    }
+    
+    sensorValue = analogRead(MQ135_PIN); 
+    Serial.print("AirQuality=");
+    Serial.print(sensorValue, DEC);
+    Serial.println(" PPM");
+  }
+}

envisens/atmega_fw/configuration.h

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+/* Macrocell environmental sensor project EnviSens
+ *  
+ * This header provides the necessary configurations for the ATMEGA firmware.
+ *  
+ *  (C) 2019 Macrocell - Environmental sensing solutions
+ *   proudly presented by Macrocell - FPGA Innovators
+ */
+
+#define SERIAL_BAUDRATE 115200
+#define OPERATION_BLINK_EN true // blink continuously if in correct operation
+#define OPERATION_PERIOD 2000 // sensor reading period in milliseconds