First commit

.gitignore

@@ -0,0 +1 @@
+credentials.h

communications.h

@@ -0,0 +1,45 @@
+/************************************* 
+ *  setup wifi communications Nodemcu
+ *************************************/
+
+#include "credentials.h"
+
+bool connect_wifi()
+{
+  Serial.print("Attempting to connect to SSID: ");
+  Serial.println(ssid);
+  WiFi.begin(ssid, pass);
+
+  // Loops for no more than 10 * (.25 + .25) = 10 seconds.
+  int loop_count = 0;
+  while((WiFi.status() != WL_CONNECTED) && (loop_count++ < 20)) {
+    digitalWrite(LED_BUILTIN, LOW);  // Flutter the LED on while we try to connect. 
+    Serial.print("*");
+    delay(250);
+    digitalWrite(LED_BUILTIN, HIGH);  // Flutter the LED on while we try to connect.
+    delay(250);
+  }
+  if (loop_count >= 20) {
+    Serial.println("\nFailed to connect, will try again later.");    
+    return false;
+  }
+
+  Serial.println("\nConnected.");
+  delay(1000);
+  return true;
+}
+
+/* Wrapper for an object method */
+long get_rssi() {
+    return WiFi.RSSI();
+}
+
+/*********************************** 
+ *  Send data to Thingspeak.
+ ***********************************/
+ void thingspeakPostData(){
+  Serial.println("thingspeaksenddata started");        
+  int result = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);
+  Serial.print("thingspeaksenddata completed, result was ");       
+  Serial.println(result);       
+}

credentials_example.h

@@ -0,0 +1,17 @@
+/*
+ Credentials example file.
+
+ Copy this file to credentials.h and substitute your actual values
+ and then restart your Arduino IDE to load the file as an editor tab.
+
+ The variables needed to connect to wifi and push to ThingSpeak.
+ */
+
+// Network used to post data to ThingSpeak.
+char ssid[] = "YourWifiSSID";
+char pass[] = "YourWifiPassword";
+
+// Thingspeak credentials.
+unsigned long myChannelNumber = 1059466;
+// You can find this in your channel API Keys tab.
+const char * myWriteAPIKey = "CHANNEL_WRITE_API_KEY";

dht22.cpp

@@ -0,0 +1,80 @@
+#include "dht22.h"
+
+
+// Number of times to re-poll the dht for temperature on error.
+int temperature_retries = 5;
+
+/**
+ * Takes Digitial pin index to set up connection.
+ */
+Dht::Dht() {}
+
+void Dht::sensorPin(int sensor_pin) {
+  this->setup(sensor_pin, DHTesp::DHT22);
+}
+
+/*
+ * Record the current values, since everything works from them.
+ * 
+ * If non-number comes back, wait 1 second and retry, up to 5 times.
+ */
+void Dht::takeMeasurements(int retries_left) {
+  Serial.println("Dht::takeMeasurements - Begin");
+
+  this->moisture = this->getHumidity();
+  this->temperature = this->getTemperature();
+
+  if(!isnan(this->moisture) && !isnan(this->temperature)) {
+    Serial.println("Dht::takeMeasurements - End");
+    return;
+  }
+
+  if (retries_left-- > 0) {
+    delay(1000);
+    Serial.print("Dht::takeMeasurements - retrying, temp ");
+    Serial.print(this->temperature);
+    Serial.print(isnan(this->moisture));
+    Serial.print(" humidity ");
+    Serial.print(this->moisture);
+    Serial.println(isnan(this->moisture));
+    this->takeMeasurements(retries_left--);
+  }
+}
+
+/**
+ * Convert cenigrate to farenheit.
+ */
+float Dht::cToF(float temp_c) {
+  Serial.print("Dht::cToF, converting temp ");
+  Serial.print(temp_c);
+  Serial.println("c");
+  return (temp_c * 1.8) + 32;
+}
+
+float Dht::humidity() {
+  return this->moisture;
+}
+
+float Dht::tempC() {
+  return this->temperature;
+}
+
+float Dht::tempF() {
+  Serial.println("Dht::tempF begin");
+  float result = this->cToF(this->temperature);
+  Serial.print("Dht::tempF, returning");
+  Serial.println(result);  
+  return result;
+}
+float Dht::heatIndexC() {
+  return this->computeHeatIndex(this->temperature, this->moisture, false);
+}
+
+float Dht::heatIndexF() {
+  return this->cToF(this->heatIndexC());
+}
+
+float Dht::dewpoint() {
+  // Based on https://create.arduino.cc/projecthub/tomwyonkman/dht11-dew-point-calculator-67b487.
+  return (this->tempC() - (100 - this->humidity()) / 5);
+}

dht22.h

@@ -0,0 +1,24 @@
+// From https://desire.giesecke.tk/index.php/2018/01/30/esp32-dht11.
+#include "DHTesp.h"
+
+#ifdef ESP32
+#pragma message(THIS EXAMPLE IS FOR ESP8266 ONLY!)
+#error Select ESP8266 board.
+#endif
+
+class Dht: public DHTesp {
+ protected:
+   float moisture, temperature;
+
+ public:
+   Dht();
+   void sensorPin(int sensor_pin);
+   void takeMeasurements(int retries_left = 5);
+   float cToF(float temp_c);
+   float tempC();
+   float tempF();
+   float heatIndexC();
+   float heatIndexF();
+   float humidity();
+   float dewpoint();
+};

gecko-tank.ino

@@ -0,0 +1,113 @@
+/*
+  Gecko tank monitor.
+
+  Monitors one dht22, updates oled temp and humidity display every second.
+  Posts sensor values to Thingspeak every 5 minutes.
+
+  Requirements:
+  - NodeMCU V2.0
+  - Thingspeak channel
+  - dht22 sensor and extension cable to reach from the circuit to inside the terrarium.
+
+- NodeMcu Pinout
+    D1 <-> DHT22
+    D2 <-> oled SDA
+    D2 <-> oled SCA
+    A0 <-> light circuit
+
+  Light circuit
+    The following all connect in one row:
+    Photocell, other end to v3.3 (measurement)
+    10k resistor to GND (pulldown)
+    Wire to A0 (signal)
+*/
+
+// Community libraries.
+#include <ESP8266WiFi.h>
+#include "ThingSpeak.h"
+
+// Application header files
+#include "communications.h"
+#include "dht22.h"
+#include "light.h"
+#include "oled.h"
+
+// Seconds between data posts to thingSpeak, this is 5 minutes.
+unsigned long THINGSPEAK_POST_FREQUENCY_SECONDS = 300;
+// For tracking loops between posts.
+unsigned long thingspeakCountdown; 
+
+// Global variables.
+WiFiClient  client;
+Dht dhtHotside;
+LightSensor light;
+
+/**
+  Run once at the beginning of the application.
+
+  Initialize the objects and variables, connect to serial monitor and wifi.
+  */
+void setup() {
+  Serial.begin(115200);
+
+  dhtHotside.sensorPin(D1);
+  light.sensorPin(A0);
+
+  ThingSpeak.begin(client);
+  oled_setup();
+
+  drawText("Connecting to Wifi", "");
+  while (!connect_wifi()) {
+    Serial.println("Failed to connect to wifi, retrying in 1 second");
+    delay(1000);
+  }
+
+  thingspeakCountdown = THINGSPEAK_POST_FREQUENCY_SECONDS;
+}
+
+/**
+  Main program loop.
+
+  Gather data, update displays, maybe post data, and then delay for a second.
+ */
+void loop() {
+  /* Gather and store all sensor values */
+  // Reading temperature or humidity takes about 250 milliseconds!
+  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
+  dhtHotside.takeMeasurements();
+  float hotside_temp_f = dhtHotside.tempF();
+  float hotside_humid_f = dhtHotside.humidity();
+  float rssi = get_rssi();
+  int lux = light.percent();
+
+  /* Send data to the serial monitor */
+  char serial_update[100];
+  sprintf(serial_update,"Hotside=%0.1ff %0.1f%% lux=%d rssi=%0.1f", 
+    hotside_temp_f,
+    hotside_humid_f,
+    lux,
+    rssi
+  );         
+  Serial.println(serial_update);
+
+  /* Send data to the oled */
+  char temp_text[100];
+  sprintf(temp_text, "%0.1ff %0.1f%%", hotside_temp_f, hotside_humid_f);
+  char title[100];
+  sprintf(title, "lux %d", lux);
+  drawText(title, temp_text);
+
+  // Send data to Thingspeak for storage when it is time.
+  if (0 == thingspeakCountdown--) {
+    ThingSpeak.setField(1, hotside_temp_f); 
+    ThingSpeak.setField(2, hotside_humid_f); 
+    ThingSpeak.setField(3, lux); 
+    ThingSpeak.setField(4, rssi); 
+    drawText("Transmitting...", "");
+    thingspeakPostData();
+
+    thingspeakCountdown = THINGSPEAK_POST_FREQUENCY_SECONDS;
+  }
+
+  delay(1000);
+}

light.cpp

@@ -0,0 +1,13 @@
+#include "light.h"
+
+LightSensor::LightSensor() {}
+
+void LightSensor::sensorPin(int pin) {
+  _pin = pin;
+}
+
+// Light value expressed in the range of 0 to 100.
+int LightSensor::percent() {
+  // Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V).
+  return analogRead(_pin) * ((float)100 / 1023.0);
+}

light.h

@@ -0,0 +1,18 @@
+// From https://www.instructables.com/id/ESP8266-Light-Sensor/
+
+#ifndef LightSensor_h
+#define LightSensor_h
+
+// Provides analogRead().
+#include "Arduino.h"
+
+class LightSensor {
+  public:
+    LightSensor();
+    void sensorPin(int pin);
+    int percent();
+  private:
+    int _pin;
+};
+
+#endif

oled.h

@@ -0,0 +1,42 @@
+#include "SSD1306Wire.h" // legacy include: `#include "SSD1306.h"`
+
+
+SSD1306Wire  display(0x3c, D3, D2);  //D2=SDK  D1=SCK  As per labeling on NodeMCU
+
+void oled_setup() {
+  delay(1000);
+  Serial.println("");
+
+  Serial.println("Initializing OLED Display");
+  display.init();
+
+  display.setFont(ArialMT_Plain_16);
+  Serial.println("Done initializing OLED Display");
+
+}
+
+void drawFontFaceDemo() {
+  // clear the display
+  display.clear();
+    // Font Demo1
+    // create more fonts at http://oleddisplay.squix.ch/
+    display.setTextAlignment(TEXT_ALIGN_LEFT);
+    display.setFont(ArialMT_Plain_10);
+    display.drawString(0, 0, "Hello world");
+    display.setFont(ArialMT_Plain_16);
+    display.drawString(0, 10, "Hello world");
+    display.setFont(ArialMT_Plain_24);
+    display.drawString(0, 26, "Hello world");
+  // write the buffer to the display
+  display.display();
+}
+
+void drawText(const char * title, const char * text) {
+  display.clear();
+  display.setTextAlignment(TEXT_ALIGN_LEFT);
+  display.setFont(ArialMT_Plain_16);  
+  display.drawString(0, 0, title);
+  display.setFont(ArialMT_Plain_24);
+  display.drawString(0, 16, text);
+  display.display();  
+}