Published September 24, 2017 © GPL3+

Room Monitor Throwie

A small and portable temperature, humidity, and light monitor that can be placed instantly anytime.

IntermediateFull instructions provided2 hours3,822

5th - 16th

ESP8266 IoT Contest - Simplify the Connected World

Things used in this project

Hardware components

Espressif Wemos D1 Mini

Adafruit DHT22 temperature and humidity sensor

Photo resistor

Software apps and online services

Arduino IDE

myDevices Cayenne

Hand tools and fabrication machines

Soldering iron (generic)

Story

Background Story

A problem that I want to solve by creating this project is that the building maintenance system at my workplace still needs to be checked manually and we have more than 30 rooms that need to be checked twice a day by one or two cleaning employees. That could be tedious for the cleaning employees that do the room checking.

There are 3 parameters need to be checked:

Is the air conditioner turned on or off?

Is the light turned on or off?

Is the room temperature and humidity fit enough for people to get comfortable?

The building has 24/7 WiFi that has the same SSID and is connected to internet, which got me thinking of making a device to make the cleaning employee's job lighter, so they can monitor every room anytime with any device and they only come to the room to turn on/off the AC and light.

The building already has its own cable system with 4 available wall plugs and to make a new device embedded on the wall could cost much more money, so the approach for making this device is that this device needs to be portable and could be plugged directly to a wall socket or can run on its own power for a long period of time.

The Hardware Build

To build this device I choose to use a Wemos D1 mini as the brain because of its small form factor. For reading the temperature and humidity I chose DHT22 because it is more reliable than the DHT11 sensor. And to read the room's light I use a basic LDR sensor because I just need to know if the light is turned on or off.

You can check the Fritzing schematic down below and make it as small and compact as possible. This is the prototype that I made so far:

The Software

For this device I use Mydevice Cayenne for the dashboard for all the device planted in the rooms because its simplicity and accessible in almost all device.

Before you upload the code make sure you follow the guide that I've been made here to make your life easier. If you already follow the guide then you can upload the code below and get your dashboard like this:

Conclusion

This device seems simple and the data parameter also seems not much but this could save a lot of time and effort needed by the building maintenance officer/employee doing his/her job. Because of that the employee could do another job sooner than they used to be.

Again, this device is simple and need some improvement such as sound sensor to check is there any person in the room by checking the sound of footsteps or people talking and also you could add any parameter depends on your need.

Code

room_throwie.ino

// This example shows how to connect to Cayenne using a manually specified Ethernet connection and send/receive sample data.

//#define CAYENNE_DEBUG
#define CAYENNE_PRINT Serial  // Comment this out to disable prints and save space
#include <CayenneMQTTESP8266.h>
#include "DHT.h"

#define DHTPIN 2     // what digital pin we're connected to

// Uncomment whatever type you're using!
//#define DHTTYPE DHT11   // DHT 11
#define DHTTYPE DHT22   // DHT 22  (AM2302), AM2321
DHT dht(DHTPIN, DHTTYPE);
// Your network name and password.
char ssid[] = "ssid";
char wifiPassword[] = "password";

// Cayenne authentication info. This should be obtained from the Cayenne Dashboard.
char username[] = "USERNAME TOKEN";
char password[] = "PASSWORD TOKEN";
char clientID[] = "CLIENT_ID TOKEN";


unsigned long lastMillis = 0;

void setup() {
  Serial.begin(9600);
  dht.begin();
  Cayenne.begin(username, password, clientID, ssid, wifiPassword);
}

void loop() {
   delay(2000);
   //Read the light value
   int lightValue = analogRead(A0)/10.24;
  
  // 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 = dht.readHumidity();
  // Read temperature as Celsius (the default)
  float t = dht.readTemperature();
  Cayenne.loop();

  //Publish data every 10 seconds (10000 milliseconds). Change this value to publish at a different interval.
  if (millis() - lastMillis > 10000) {
    lastMillis = millis();
    //Write data to Cayenne here. This example just sends the current uptime in milliseconds.
    Cayenne.virtualWrite(0, h);
    //Some examples of other functions you can use to send data.
    Cayenne.celsiusWrite(1, t);
    Cayenne.luxWrite(2, lightValue);
    //Cayenne.virtualWrite(3, 50, TYPE_PROXIMITY, UNIT_CENTIMETER);
  }
}

//Default function for processing actuator commands from the Cayenne Dashboard.
//You can also use functions for specific channels, e.g CAYENNE_IN(1) for channel 1 commands.
CAYENNE_IN_DEFAULT()
{
  CAYENNE_LOG("CAYENNE_IN_DEFAULT(%u) - %s, %s", request.channel, getValue.getId(), getValue.asString());
  //Process message here. If there is an error set an error message using getValue.setError(), e.g getValue.setError("Error message");
}

Credits

Hendra Kusumah

32 projects • 130 followers

Love hacking and making new things from IoT to robotics

Comments

Awards

5th - 16th

ESP8266 IoT Contest - Simplify the Connected World

Room Monitor Throwie