Published December 8, 2021 © MIT

How to save money with IOT

Use IOT to detect errors in the night setback function of your heating system and save costs through effective heating settings.

BeginnerFull instructions provided2 hours1,099

Things used in this project

Hardware components

M5Stack M5StickC ESP32-PICO Mini IoT Development Board

Adafruit MCP9808 High Accuracy I2C Temperature Sensor

Adafruit Contact-less Infrared Thermopile Sensor Breakout - TMP006

Software apps and online services

PlatformIO IDE

Circus of Things

Story

#25projectsofchristmas

Night setback of heating systems

When you are at home, chilling in the living room, you like to have it cozy and warm. Especially in winter. Central heating systems give us warmth without having to cut down trees and chop wood. Very practical! And since the apartment is not needed so warm when you are not at home, or when you lie in bed at night, you can simply turn down the heating system at these times. And really convenient is that this can be controlled automatically by a switching time clock thermostat.

Imagine that you measure the room temperature in your living room and at the same time the temperature of the radiator. Then you will get the following picture for typical winter days:

Night setback and heating phases over two winter days

At the times of night setback the apartment is not heated. This is not necessary, because I lie in bed and sleep under my warm blanket. And when the heating is not on, I save money! (indicated by the EURO Symbols). The graph shows a weekend when I was at home during the day. During the week I am at work during the day. Then I don't need to heat my apartment either, because my boss heats the office at my workplace. This means that I can also turn down the heating during the day. And that saves me more money:

Day and night setback can save a lot of money!

By the way, the short dips in the living room temperature always occur when I briefly ventilate the apartment by opening the windows. Good to see, isn't it?

Failure detection

My central heating has a main valve through which the night setback is controlled. And one day, exactly this valve broke! It stayed open permanently. As a result, I was constantly heating my apartment. Even if the room thermostat with the switching time clock should actually switch off the heating:

1 / 3 • Days and nights without working night setback

I burned money on those days but I discovered the error in time and was able to fix it quickly. Therefore, it is important to keep an eye on the heating and check its operation. And this is where IOT comes into action.

Sensors and data acquisition

The M5StickC is the perfect choice for recording temperatures. He can be easily integrated into the WiFi of my apartment to transfer the data to an IOT server. There are plug-on modules (HATs) with which the device can be easily expanded. For example with the M5StickC ENV HAT which contains the following sensors: DHT12, BMP280 and BMM150. The DHT12 is a digital temperature and humidity sensor that is controlled via I2C. However, the temperature I measured with the DHT12 of the ENV-HAT was a few degrees too high:

1 / 2 • Room temperature measured with the ENV HAT

It turns out that the heat from the M5StickC affects the sensor's measurements when the sensor is too close to the electronics and the screen of the M5StickC. If the sensor is connected with cables so that it is placed a bit away, then the readings make sense:

1 / 2 • Sensor connected via wires to keep it away from the electronics and the screen.

However, for the measurements of the room temperature and the temperature of the radiator, I decided to use sensors with a higher precision.

1 / 3 • Measurement setup: Two sensors, one M5StickC and a USB power supply

For the measurement of the room temperature I decided to use the MCP9808 High Accuracy I2C Temperature Sensor. The sensor is available as a breakout board from Adafruit. It is very precise and can be easily addressed via a library. The sensor only needs to be positioned at a good place in the room and then measures the ambient temperature in my living room.

1 / 2 • The MCP9808 Breakout Board

To measure the temperature of the radiator I decided to use the Contact-less Infrared Thermopile Sensor TMP006. This sensor was also available as a breakout board from Adafruit. The contact-less measurement simplified the installation: The sensor only has to be mounted in such a way that it is directed to the supply pipes of the radiator. It does not need to touch the radiator itself.

1 / 5 • The TMP006 Breakout board

Both sensors are controlled via I2C and have different I2C addresses. Important: The sensors are not connected to the M5StickC via the Grove connector, because the I2C inputs of the ESP32 are not 5V tolerant. The Grove-Connector has 5V power output. The breakout boards can handle 5V as supply voltage, but then the I2C signal lines are also at 5V. Therefore it is better to supply the boards with 3.3V.

Circus-of-Things

Every 10 minutes the measured values from both sensors are sent to the Circus-of-Things server. There they are stored and can be viewed via a web interface. The time range of almost two years looks like this:

1 / 2 • Circus-of-Things Web interface with two years of data (almost)

To use the Circus-of-Things service you must first create an account. In the account information you will then find the necessary data for the connection via the REST API (token).

1 / 2 • Web page of the Circus-of-Things server

Then you have to create a signal in the web interface, to which the data will be sent.

1 / 4 • Creation of a new signal

How the Code Works

The code starts with including the libraries for the sensors and the declaration of the sensor objects:

// MCP9808 sensor library:
#include "Adafruit_MCP9808.h"
// MCP9808 sensor object:
Adafruit_MCP9808 tempsensor1 = Adafruit_MCP9808();
#define MCP9808_I2CADDR 0x18
#define MCP9808_RES 3

// Required for all Adafruit Unified Sensor based libraries.
#include <Adafruit_Sensor.h>

// TMP006 sensor library:
#include "Adafruit_TMP006.h"
#define TMP006_I2CADDR 0x40
// TMP006 sensor object:
Adafruit_TMP006 tempsensor2(TMP006_I2CADDR);

Followed by the configuration data for the local WiFi and the connection to the Circus-of-Things Server:

// WiFi network configuration:
const char* ssid     = "YourWiFi";
const char* password = "Your_Password";

// circusofthings.com configuration
const char* Circus_hostname = "circusofthings.com";
const char* Circus_key1 = "your-key#1";
const char* Circus_key2 = "your-key#2";
const char* Circus_token = "your-token";

For the output of information and data on the display of the M5StickC I used my textbuffer library.

The setup() function is simple: First the M5StickC and the display are initialized. Then a scan is performed on the I2C bus and the devices found are displayed. This is useful to find errors with the I2C wiring. After that the sensors are initialized and at last the connection to the WiFi is established.

In the main loop(), a check is made every 10 minutes to see whether the connection to the WiFi still exists. Then the data of the sensors are read out and shown on the display as well as sent to the Circus-of-Things server.

For the connection to the Circus-of-Things Server, you can find good documentation on the website and also libraries to learn how to use the service. But don't worry: it's really easy! To make the upload work best in my code, I wrote a small custom function that connects to, and uploads the measured value to the Circus-of-Things Server:

// =============================================================
// Circus_write(double value)
// send value to circusofthings.com website
// the hostname, token and key need to be configured
// The function returns the number of received lines
// =============================================================
int Circus_write(const char* Circus_key, double value) {
// Use WiFiClient class to create TCP connection
WiFiClientSecure client;
// Needs to be set Insecure, otherwise sometimes errors will occur
client.setInsecure();
const int httpsPort = 443;
if(verbose_output) Serial.printf("--> connect to: %s:%i\r\n",Circus_hostname,httpsPort);
int n_lines = 0;
// check the connection
if (!client.connect(Circus_hostname, httpsPort)) {
Serial.println("[ERR] Circus Connection failed!!!");
return 0;
} else {
char value_char[15];
dtostrf(value,1,4,value_char);
// We now create a URI for the request
char url_char[250];
sprintf_P(url_char, PSTR("/WriteValue?Key=%s&Value=%s&Token=%s\r\n"), Circus_key, value_char, Circus_token);
String url_str = url_char;
if(verbose_output) {
Serial.print("Requesting URL: ");
Serial.println(Circus_hostname+url_str);
}
// We need to manually create the HTTP GET message
// client.print() will send the request to the server
client.print(String("GET ") + url_str + " HTTP/1.1\r\n" +
"Host: " + Circus_hostname + "\r\n" +
"Connection: close\r\n\r\n");
//Wait until a response is available
int n_trials = 500;
while(!client.available() && n_trials > 0){
n_trials--;
delay(10);
}
// Read all the lines of the reply from server
// force timeout to 1000ms (ESP8266 = 5000ms default value)
client.setTimeout(1000);
while(client.available()){
String line = client.readStringUntil('\r');
n_lines++;
if(verbose_output) Serial.print(line);
}
if(verbose_output) Serial.printf("\n[OK] %i lines received\n",n_lines);
}
return n_lines;
}

Every 10 minutes, both data from the sensors are sent to the server by calling this function for both values:

// Write the measured speed to circusofthings.com
Circus_write(Circus_key1, temperature1);
Circus_write(Circus_key2, objtemp2);

End of life products

When I started the project in early 2020, the sensors were still up to date. In the meantime, the TMP006 sensor is no longer available. Also the follow-up model TMP007 is "discontinued" at Adafruit. But there is a NCIR Non-Contact Infrared Thermometer Sensor Unit from M5Stack. This one would be suitable for rebuilding this project and can be connected directly to the Grove port.

The MCP9808 breakout board is still available, but from M5Stack you can get the ENV III unit. This Unit can also be connected directly to the Grove port. With the Grove-T connector both units can be connected in series and no soldering is necessary. All you need are long Grove cables.

Feedback

I hope this project can prove to be useful to the wider community. Feel free to message me here if you have questions or comments.

Enjoy and let's save money and resources!

Regards,

Hans-Günther

Code

main.cpp

/******************************************************************************
 * IOT Temperature logger via Circus Of Things based on M5StickC
 * 
 * Use IOT to detect errors in the night setback function of your heating 
 * system and save costs through effective heating settings. Keep an eye
 * on your heating system to save money!
 * For more information check the project page at Hackster.io
 * https://www.hackster.io/hague/how-to-save-money-with-iot-16b177
 * 
 * Hague Nusseck @ electricidea
 * v0.5 08.Mar.2020
 * 
 * code on github:
 * https://github.com/electricidea/M5StickC-IOT-Temp-logger
 * 
 * https://circusofthings.com/
 * for more information about Circus-of-Things:
 * https://www.hackster.io/jaume_miralles/monitoring-temperature-and-humidity-with-esp32-f53465
 *  
 * Distributed as-is; no warranty is given.
 ******************************************************************************/
#include <Arduino.h>

// M5StickC library:
#include <M5StickC.h>
// Install for PlatformIO:
// pio lib install "M5StickC"

// MCP9808 sensor library:
#include "Adafruit_MCP9808.h"
// Install for PlatformIO:
// pio lib install "Adafruit MCP9808 Library"

// MCP9808 sensor object:
Adafruit_MCP9808 tempsensor1 = Adafruit_MCP9808();

// MCP9808 I2C Adress
//  A2 A1 A0 address
//  0  0  0   0x18  this is the default address
//  0  0  1   0x19
//  0  1  0   0x1A
//  0  1  1   0x1B
//  1  0  0   0x1C
//  1  0  1   0x1D
//  1  1  0   0x1E
//  1  1  1   0x1F
#define MCP9808_I2CADDR 0x18

// MCP9808 Resolution:
// Mode Resolution SampleTime
//  0    0.5°C       30 ms
//  1    0.25°C      65 ms
//  2    0.125°C     130 ms
//  3    0.0625°C    250 ms
#define MCP9808_RES 3

// Required for all Adafruit Unified Sensor based libraries.
#include <Adafruit_Sensor.h>
// Install for PlatformIO:
//pio lib install "Adafruit Unified Sensor"

// TMP006 sensor library:
#include "Adafruit_TMP006.h"
// Install for PlatformIO:
// pio lib install "Adafruit TMP006"

// The default address of the TMP006 is 0x40. 
// By connecting the address pins as in the following table, 
// you can generate any address between 0x40 and 0x47
//  A2 A1 A0 address
//  0  0  0   0x40  this is the default address
//  0  0  1   0x41
//  0  1  0   0x42
//  0  1  1   0x43
//  1  0  0   0x44
//  1  0  1   0x45
//  1  1  0   0x46
//  1  1  1   0x47
#define TMP006_I2CADDR 0x40

// TMP006 sensor object:
Adafruit_TMP006 tempsensor2(TMP006_I2CADDR); 

// Time library;
#include <TimeLib.h>
// pio lib install "Time"
// lib_deps = Time

// Buffer values for Seconds and minutes
// to perform a test every minute
uint8_t last_second;
int second_count;

// WIFI and https client librarys:
#include "WiFi.h"
#include <WiFiClientSecure.h>

// WiFi network configuration:
const char* ssid     = "YourWiFi";
const char* password = "YourPassword";

// circusofthings.com configuration
const char* Circus_hostname = "circusofthings.com";
const char* Circus_key1 = "Your_key1";
const char* Circus_key2 = "Your_key2";
const char* Circus_token = "Your_token";


// Library for a simple text buffer scrolling display
#include "tb_display.h"
// https://www.hackster.io/hague/m5stickc-textbuffer-scrolling-display-fb6428
// https://github.com/electricidea/M5StickC-TB_Display

// Display brightness level
// possible values: 7 - 15
uint8_t screen_brightness = 10; 

// scren Rotation values:
// 1 = Button right
// 2 = Button above
// 3 = Button left
// 4 = Button below
int screen_orientation = 1;

// verbose level (serial output):
// TRUE = lot of data
// FALSE = only time and speed data (table format)
#define verbose_output false

// function forward declaration
boolean connect_Wifi();
int Circus_write(const char* Circus_key, double value);
void scan_I2C_bus();

void setup() {
  // initialize the M5Stack object
  m5.begin();
  // initialize I2C for the M5Stick HAT-Pins
  Wire.begin(0, 26);
  // set screen brightness
  M5.Axp.ScreenBreath(screen_brightness);

  // print a welcome message over serial porta
	Serial.println("===================");
	Serial.println("     M5StickC");
	Serial.println("Temperature logger");
	Serial.println(" 08.03.2020 v0.5");
	Serial.println("===================");

  // init the text buffer display and print welcome text on the display
  tb_display_init(screen_orientation);
  tb_display_print_String("        M5StickC\n\n   Temperature logger\n");
  delay(2000);
  // scan I2C Bus to detect the sensors
  scan_I2C_bus();
  delay(2000);

  // init MCP9808 Temp Sensor
  if (tempsensor1.begin(MCP9808_I2CADDR)) {
    Serial.println("[OK] MCP9808 found");
    tb_display_print_String("[OK] MCP9808 found\n");
  } else {
    Serial.println("[ERR] Couldn't find MCP9808!");
    tb_display_print_String("[ERR] Couldn't find MCP9808!\n");
  }
  tempsensor1.setResolution(MCP9808_RES);

  // init TMP006 Temp Sensor
  // you can also use tmp006.begin(TMP006_CFG_1SAMPLE) or 2SAMPLE/4SAMPLE/8SAMPLE to have
  // lower precision, higher rate sampling. default is TMP006_CFG_16SAMPLE which takes
  // 4 seconds per reading (16 samples)
  if (tempsensor2.begin()) {
    Serial.println("[OK] TMP006 found");
    tb_display_print_String("[OK] TMP006 found\n");
  } else {
    Serial.println("[ERR] Couldn't find TMP006!");
    tb_display_print_String("[ERR] Couldn't find TMP006!\n");
  }
  // wake up MCP9808 and TMP006
  Serial.println("wake up MCP9808.... "); 
  tempsensor1.wake();  
  Serial.println("wake up TMP006.... ");
  tempsensor2.wake();

  // Set WiFi to station mode and disconnect
  // from an AP if it was previously connected
  WiFi.mode(WIFI_STA);
  WiFi.disconnect();
  // connect to the configured AP
  connect_Wifi();
  // first measurement in 30 seconds
  last_second = second(now());
  second_count = 600 - 30;
}

void loop() {
  M5.update();
  // get actual time
  time_t t=now();

  // call every second:
  if (second(t) != last_second) {
    last_second = second(t);
    // increase to count 600 seconds = 10 minutes
    second_count++;
  }
  // call every 600 seconds:
  if (second_count >= 600) {    
    // check for Wire errors
    Serial.print("\nWire State: ");
    Serial.println(Wire.getErrorText(Wire.lastError()));

    float temperature1 = tempsensor1.readTempC();
    Serial.printf("Temp1: %2.1f *C\n", temperature1);

    float objtemp2 = tempsensor2.readObjTempC();
    Serial.print("Object Temperature: "); Serial.print(objtemp2); Serial.println("*C");
    float dietemp2 = tempsensor2.readDieTempC();
    Serial.print("Die Temperature: "); Serial.print(dietemp2); Serial.println("*C");

    char String_buffer[128]; 
    snprintf(String_buffer, sizeof(String_buffer), "Temp: %2.1f / %2.1f *C\n", temperature1, objtemp2);
    tb_display_print_String(String_buffer);
    // check if WIFI is still connected
    // if the WIFI ist not connected (anymore)
    // a reconnect is triggert
    wl_status_t wifi_Status = WiFi.status();
    if(wifi_Status != WL_CONNECTED){
      // reconnect if the connection get lost
      Serial.println("[ERR] Lost WiFi connection, reconnecting...");
      tb_display_print_String("[ERR] Lost WiFi!\n");
      if(connect_Wifi()){
        Serial.println("[OK] WiFi reconnected");
        tb_display_print_String("[OK] reconnected\n");
      } else {
        Serial.println("[ERR] unable to reconnect");
        tb_display_print_String("[ERR] unable to reconnect\n");
      }
    }
    // check if WIFI is connected
    // needed because of the above mentioned reconnection attempt
    wifi_Status = WiFi.status();
    if(wifi_Status == WL_CONNECTED){
      if(verbose_output) {
        Serial.print("[OK] WiFi connected / "); 
        Serial.print("IP address: ");
        Serial.println(WiFi.localIP());
        Serial.println("-----------------------");
      }
      // Write the measured speed to circusofthings.com
      Circus_write(Circus_key1, temperature1);
      Circus_write(Circus_key2, objtemp2);
    }
    // prepare the next call in one minute
    t=now();
    last_second = second(t);
    second_count = 0;
  }
}


// =============================================================
// connect_Wifi()
// connect to configured Wifi Access point
// returns true if the connection was successful otherwise false
// =============================================================
boolean connect_Wifi(){
  // Establish connection to the specified network until success.
  // Important to disconnect in case that there is a valid connection
  WiFi.disconnect();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  char String_buffer[128]; 
  snprintf(String_buffer, sizeof(String_buffer), "\nConnecting to:\n  %s\n",ssid);
  tb_display_print_String(String_buffer);
  delay(1500);
  //Start connecting (done by the ESP in the background)
  WiFi.begin(ssid, password);
  // read wifi Status
  wl_status_t wifi_Status = WiFi.status();
  int n_trials = 0;
  // loop while Wifi is not connected
  // run only for 20 trials.
  while (wifi_Status != WL_CONNECTED && n_trials < 20) {
    // Check periodicaly the connection status using WiFi.status()
    // Keep checking until ESP has successfuly connected
    wifi_Status = WiFi.status();
    n_trials++;
    switch(wifi_Status){
      case WL_NO_SSID_AVAIL:
          Serial.println("[ERR] WIFI SSID not available");
          tb_display_print_String("[ERR] SSID not available\n");
          break;
      case WL_CONNECT_FAILED:
          Serial.println("[ERR] WIFI Connection failed");
          tb_display_print_String("[ERR] Connection failed\n");
          break;
      case WL_CONNECTION_LOST:
          Serial.println("[ERR] WIFI Connection lost");
          tb_display_print_String("[ERR] Connection lost\n");
          break;
      case WL_DISCONNECTED:
          Serial.println("[STATE] WiFi disconnected");
          tb_display_print_String("[STATE] disconnected\n");
          break;
      case WL_IDLE_STATUS:
          Serial.println("[STATE] WiFi idle status");
          tb_display_print_String("[STATE] WiFi idle\n");
          break;
      case WL_SCAN_COMPLETED:
          Serial.println("[OK] WiFi scan completed");
          tb_display_print_String("[OK] WiFi scan completed\n");
          break;
      case WL_CONNECTED:
          Serial.println("[OK] WiFi connected");
          tb_display_print_String("[OK] WiFi connected\n");
          break;
      default:
          Serial.println("[ERR] WIFI unknown Status");
          tb_display_print_String("[ERR] WIFI unknown Status\n");
          break;
    }
    delay(500);
  }
  if(wifi_Status == WL_CONNECTED){
    // if connected
    Serial.print("IP address: ");
    Serial.println(WiFi.localIP());
    snprintf(String_buffer, sizeof(String_buffer), "IP: %s\n",WiFi.localIP().toString().c_str());
    tb_display_print_String(String_buffer);
    return true;
  } else {
    // if not connected
    Serial.println("[ERR] unable to connect Wifi");
    tb_display_print_String("[ERR] unable to connect\n");
    return false;
  }
}


// =============================================================
// Circus_write(double value)
// send value to circusofthings.com website
// the hostname, token and key need to be configured
// The function returns the number of received lines
// =============================================================
int Circus_write(const char* Circus_key, double value) {
  // Use WiFiClient class to create TCP connection
  WiFiClientSecure client;
  // Needs to be set Insecure, otherwise sometimes errors will occur
  client.setInsecure();
  const int httpsPort = 443;
  if(verbose_output) Serial.printf("--> connect to: %s:%i\r\n",Circus_hostname,httpsPort);
  int n_lines = 0;
  // check the connection
  if (!client.connect(Circus_hostname, httpsPort)) {
    Serial.println("[ERR] Circus Connection failed!!!");
    return 0;
  } else {
    char value_char[15];
    dtostrf(value,1,4,value_char);
    // We now create a URI for the request
    char url_char[250];
    sprintf_P(url_char, PSTR("/WriteValue?Key=%s&Value=%s&Token=%s\r\n"), Circus_key, value_char, Circus_token);
    String url_str = url_char;
    if(verbose_output) {
      Serial.print("Requesting URL: ");
      Serial.println(Circus_hostname+url_str);
    }
    // We need to manually create the HTTP GET message
    // client.print() will send the request to the server
    client.print(String("GET ") + url_str + " HTTP/1.1\r\n" +
                 "Host: " + Circus_hostname + "\r\n" +
                 "Connection: close\r\n\r\n");
    //Wait until a response is available
    int n_trials = 500;
    while(!client.available() && n_trials > 0){
      n_trials--;
      delay(10);
    }
    // Read all the lines of the reply from server
    // force timeout to 1000ms (ESP8266 = 5000ms default value)
    client.setTimeout(1000);
    while(client.available()){
      String line = client.readStringUntil('\r');
      n_lines++;
      if(verbose_output) Serial.print(line);
    }
    if(verbose_output) Serial.printf("\n[OK] %i lines received\n",n_lines);
  }
  return n_lines;
}


//==============================================================
// Scanning I2C adresses from 1 to 127
// and display all available devices
void scan_I2C_bus(){
  int address;
  int error;
  char String_buffer[128]; 
  tb_display_print_String("Scan I2C Bus:\n");
  for(address = 1; address < 128; address++) 
  {
    Wire.beginTransmission(address);
    error = Wire.endTransmission();
    if(error==0)
    {
      snprintf(String_buffer, sizeof(String_buffer), " %.2X ",address);
      tb_display_print_String(String_buffer);
    }
    else 
      // no device found at this address
      tb_display_print_char('.');
    delay(25);
  }
  tb_display_print_char('\n');
}

Credits

Hans-Günther Nusseck

17 projects • 51 followers

Just a guy who can't pass by any hardware without wondering how it works. Managing robot based industrial automation projects for living.

How to save money with IOT

Things used in this project

Hardware components

Software apps and online services

Story

Night setback of heating systems

Failure detection

Sensors and data acquisition

Circus-of-Things

How the Code Works

End of life products

Feedback

Schematics

Schematics

Code

main.cpp

github repository

Credits

Hans-Günther Nusseck

Comments

Embed the widget on your own site

How to save money with IOT

How to save money with IOT

Things used in this project

Hardware components

Software apps and online services

Story

Night setback of heating systems

Failure detection

Sensors and data acquisition

Circus-of-Things

How the Code Works

End of life products

Feedback

Schematics

Schematics

Code

main.cpp

github repository

Credits

Hans-Günther Nusseck

Comments

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