Alexa/ Google Home App controlled LED Strip

This project is a part of our academic course Internet of Things (CSN-527).

Problem Statement

Control an addressable LED Strip using Alexa/ Google Home App. We should be able to do the following:

• Turn ON/OFF the LEDs
• Change the Brightness
• Change the Color of LEDs

Motivation

The motivation behind this project is to leverage the power of Internet of Things (IoT) technology and voice-controlled virtual assistants to create a smart and convenient lighting solution for homes. It aims to provide a seamless way for users to control their LED strip lights using voice commands through voice assistants like Alexa and Google Home app thus reducing the need for manual control.

This project seeks to improve the user experience by making lighting control more efficient, convenient, and modern. With the integration of IoT technology, users can control their LED strip lights from anywhere in their homes using voice commands, without having to physically access the switch or even use their smartphones. This can be especially beneficial for individuals with mobility issues, disabilities, or those who simply prefer a hands-free approach to home automation.

Devices Used

• ESP8266
• Addressable LED Strip(WS2812B)
• Push Button
• Female Jumper Wires

Here the Push Button acts as a manual switch for the LED Strip.

Software Components Used

• FastLED.h library
• Wifi.h library for wifi provisioning
• SinricPro, SinricProLight
• SinricPro / ESP Rainmaker web platform and apps
• AsyncElegantOTA.h, ArduinoOTA.h (for OTA functionality)
• UbidotsESPMQTT.h (for Ubidots integration)
• AsyncMqttClient
• Arduino IDE
• Alexa, Google home app

Most of IoT devices use lightweight MQTT protocol to exchange messages with IoT clouds. On the other hand Alexa /Google Assistant use REST APIs services. In such scenario platforms like ESP Rainmaker, SinricPro provides users with interface that can understand REST as well as MQTT. We are using Sinric Pro Library.

Sincric Pro Library provides us with a higher level interface to connect to IoT Cloud without knowing specifics of MQTT protocol.

Circuit Diagram

The WS2812B LED strip is powered using the ESP8266 5V, thus ESP8266 5V is connected to the VCC on the LED Strip. The ESP8266 GND is connected to the GND on the LED Strip. We connect the DATA of LED strip to the D0 pin on ESP8266.

The Push Button is powered using the ESP8266 3.3V, thus ESP8266 3.3V is connected to the VCC on the Push Button. The ESP8266 GND is connected to the GND on the Push Button. We connect the DATA of Push Button to the D1 pin on ESP8266.

Functionalities Offered

• Controlling LED Strip using Alexa/ Google Home app using Sinric Pro Library
  • User can say "Hey Google! Decrease the brightness by 50% of Living Room LED", and the brightness will be decreased by 1/2.
• Multiple Light modes available for the Smart Bulb which can be controlled using Alexa app
  • Created Custom Device template using Sinric Pro library
  • Users can change from Normal to blinking Party mode in just a click
• OTA functionality added which allows user to upload a new sketch using wifi
  • Done using AsyncElegantOTA as well as ArduinoOTA library
  • Useful in case of when we don't have physical access to the Board and we want to make some updates
• PowerSaver Option available
  • If turned ON, it keeps reducing the brightness by 50% for every inactive interval of 60 seconds
• Data Analysis using Ubidots integration
  • These plots can be used to analyze the usage of the LEDs

Code Setup

Install ESP8266

• Include library <ESP8266WiFi.h> and install ESP8266 Board in Arduino IDE. For installation, go to Arduino IDE and follow the path File/preferences and open the preference tab. Paste the link http://arduino.esp8266.com/stable/package_esp8266com_index.json in the additional board manager URL box.
• After this, go to Tool/ Board Tools/board/board manager and type ESP8266.
• You will find a board of ESP8266 click on the install option to get the board installed.

For Smart Bulb

1. Sign up in Sinric Pro
   • Click on Devices, then click on Add Device
   • Add the Device Name(call it Smart Bulb), description and Device Type(Smart Light Bulb)
   • Sinric Pro associates every Device with a DeviceID(let's call it Light_ID)
2. Now update the Light_ID, your App key and App secret and the Wifi credentials in the code(Arduino_code/substitute/substitute.ino).

For Smart LED

1. Sign up in Sinric Pro
   • Click on Device Templates, then click on Add Device Template
   • Add the Template Name(eg: LedStrip), description and Device Type(Smart Light Bulb)
   • Select capabilities by drag and drop. We can only choose 3 in non-premimum mode.
     • Select Power, Mode and Brightness
     • Configure Mode, add Mode name as Theme and add new mode values
     • To replicate our code, add mode values as Party, Power Saver, Normal, Cloudy
   • Now click on Devices, then click on Add Device
   • Add the Device Name(call it Smart LED), description and Device Type
     • Select the Device Type as the Device Template you just created(LedStrip).
   • Sinric Pro associates every Device with a DeviceID(let's call it Light_ID)
2. Now update the Light_ID, your App key and App secret and the Wifi credentials in the code(Arduino_code/main/main.ino).

For C server

1. The C sever uses Paho MQTT C client library. The steps to install and build the library is written below:
   • Move to the folder where you want to install Paho MQTT C client library and let it be $DEST_PATH . Open the terminal.

    $ sudo apt-get install build-essential gcc make cmake cmake-gui cmake-curses-gui git doxygen graphviz libssl-dev
    $ git clone https://github.com/eclipse/paho.mqtt.c.git
    $ cd paho.mqtt.c
    $ cmake -Bbuild -H. -DPAHO_WITH_SSL=ON
    $ sudo cmake --build build/ --target install
    $ sudo ldconfig

2. Move to the folder containing C analyser code. In order to compile the code run the following command in the terminal.

    $ gcc -L${DEST_PATH}/paho.mqtt.c/build/output -o server analyser.c -lpaho-mqtt3c -lpthread

3. In order to run the server type the command.

    $ ./server     

Install Mosquittto Broker

1. Install the mosquitto package.

    $ sudo apt install -y mosquitto     

2. The mosquitto package should now load on your server. Confirm the status of the mosquitto service (Ensure that the mosquittto package is loaded and active).

    $ sudo systemctl status mosquitto 

3. Once running, you can manage the mosquitto services by executing the following commands.
   • Stop the mosquitto service:

     $ sudo systemctl stop mosquitto

   • Start the mosquitto service:

     $ sudo systemctl start mosquitto

   • Restart the mosquitto service:

     $ sudo systemctl restart mosquitto

4. By default, the mosquittto broker will not handle anonymous connections. The server compiled by analyser.c and the client written in the sketch doesn't use any authentication service. In order to make the mosquittto broker listen to anonymous clients, we need to tweak the configration file as shown below.

    $ sudo nano /etc/mosquitto/conf.d/default.conf
   

   Now add the following lines in the file :

   listener 1883
   allow_anonymous true
   

5. Restart the mosquittto broker.

Install FastLED library.

1. Click here to download the FastLED library from the offical github repository in .zip format.
2. Open the Arduino IDE. Move to the Sketch > Include Library > Add .ZIP library.
3. Enter the destination of the downloaded fastLED zip folder.
4. Arduino wil add the library in the sketch.

Working

This section shows the workflow of the project.

Smart Bulb

Arduino Script Design for Smart Bulb
Code is available at Arduino_code/substitute/substitute.ino

1. The ESP8266 first connects to the WIFI using the specified credentials.
2. We have created a new Light Device using Sinric Pro library. Like: SinricProLight &myLight = SinricPro[*Light_ID*]
   • This is the Light Device associated with the Smart Bulb we created on the Sinric Pro library.
3. This library has callback functions that are called every time a variable is changed. We define the callback function for this light device.
4. onPowerState callback function will be called everytime PowerState of the myLight will change on the Cloud.

bool onPowerState(const String &deviceId, bool &state) { powerState = state; if (state) { FastLED.setBrightness(map(globalBrightness, 0, 100, 0, 255)); // Turn ON the LEDs } else { FastLED.setBrightness(0); // Turn OFF the LEDs } FastLED.show(); return true; }

6. onBrightness, onAdjustBrightness and *onColor" callback functions are also defined.
7. We have also integrated Ubidots where we send the PowerState variable's values to the cloud.
8. Now the following code runs in loop
   • The function handleButtonPress which handles the push button. It checks if the push button is being pressed or not, if yes then it toggles the Power state of the LEDs.
     • To update the PowerState back to the Cloud, we use the function sendPowerStateEvent() provided by the Sinric Pro library with the newly updated value of PowerState.
   • Then it checks if its been more than 10 seconds that we sent an update to Ubidots, if yes then it sents the updated PowerState to Ubidots.
   • Then it handles any updates from the Sinric Pro platform which includes updates from Alexa/ Google Home aap and the Sinric Pro app.
     • If user turns OFF the Smart Bulb using any of the above specified platform
     • The callback function corresponding to PowerState i.e onPowerState is called and the FastLED finally turns OFF the LED.
     • If user changed the color of the Smart Bulb using any of the above specified platform
     • The callback function corresponding to color i.e onColor is called and the FastLED finally sets the color to the specified one.

Smart LED

Arduino Script Design for Smart LED
Code is available at Arduino_code/main/main.ino

1. The ESP8266 first connects to the WIFI using the specified credentials.
2. We have created a new LedStrip Device using Sinric Pro library. Like: LedStrip &ledStrip = SinricPro[DEVICE_ID];
   • This is the Light Device associated with the Smart LED we created on the Sinric Pro library.
3. This library has callback functions that are called every time a variable is changed. We define the callback function for this light device.
4. onPowerState callback function will be called everytime PowerState of the ledStrip will change on the Cloud.
5. Similarly, onBrightness, onAdjustBrightness and *onColor" callback functions are also defined.
6. We have created another callback function onSetMode that will be called evertime the Mode of this ledStrip device is being changed at the Cloud (either using the Alexa app or using the Sinric Pro app).
   • We have created different functions that create different light patterns corresponding to different Light Modes.
7. For the Power Saver mode, we have created a C server (analyser.c) which uses MQTT protocol to publish and subscribe to the topics.
   • We use the Mosquitto Broker.
   • Here our ESP8266 and the C server both acts as MQTT client.
   • C server has subscribed to the powerSave/analysis topic and publishes to the powerSave/alert topic.
   • ESP8266 has subscribed to the powerSave/alert topic and publishes to the powerSave/analysis topic.
   • When Power Saver mode is turned ON, enabled variable is set as 1.
8. Now the following code runs in loop
   • The function handleButtonPress which handles the push button. It checks if the push button is being pressed or not, if yes then it toggles the Power state of the LEDs.
     • To update the PowerState back to the Cloud, we use the function sendPowerStateEvent() provided by the Sinric Pro library with the newly updated value of PowerState.
   • Then it checks if its been more than 10 seconds, if yes:
     • It checks if the PowerSaver was enabled, if it was enabled, it puts globalState in the message payload.
     • Otherwise it puts the globalPowerState in the message payload
     • We then publish this message to the broker with the topic to which C server has subscribed.
     • On C server, we have a variable last_update_time which is set to -1 if the PowerSave mode is OFF, otherwise it is set to the last time any update was made to the Smart LED.
     • On C server, a function publishThread() is running on a separate which is checks if last_update_time is still -1 or not
     • On receiving this message, C server checks if the PowerSaver option was enabled or not by checking the message payload. It updates the last_update_time to -1 if the PowerSave mode not enabled, else set to the current time.
     • Whenever last_update_time is differnt from -1, publishThread() checks if it has been more than 60 seconds between last update and current time, if yes then it publishes message with "inactive" as payload to the broker with topic powerSave/alert.
     • ESP8266 receives the message from broker from topic powerSave/alert and then calls the onMqttMessage(). It then checks if the message payload is "inactive", if yes then it reduces the brightness by 50% using the setBrightness function of FastLED.
   • Then it handles any updates from the Sinric Pro platform which includes updates from Alexa/ Google Home aap and the Sinric Pro app.
     • If user turns OFF the Smart LED using any of the above specified platform
     • The callback function corresponding to PowerState i.e onPowerState is called and the FastLED finally turns OFF the LED.
     • If user changed the mode of the Smart LED using Alexa or Sinric Pro app
     • The callback function corresponding to mode i.e onSetMode is called and the FastLED finally changes the mode.

Extensions

Power Saver

It is an option which we can enable. If this option is enabled, it reduces the brightness by 50% for every inactive interval of 60 seconds. For this we have created a C server analyser.c which makes use of MQTTClient.h library. (Working is explained above)

OTA functionality

We have added OTA feature so that user can upload a new sketch whenever required without the necessity of having the serial connection with the ESP8266 board. We have used AsyncElegantOTA library in out Smart Bulb code. For this we included the AsyncElegantOTA.h library. We have created a AsyncWebServer on the port 80 namely OTA_server. Then we setup the AsyncOTA and begin this OTA_server. To upload a new sketch go to localhost/update. The below image is the update page.

Data Integration with Ubidots

We have integrated Ubidots using the MQTT protocol in the Smart Bulb code. It sends the updated value of the PowerState variable to the Ubidots after every 10 seconds. This data can be analyzed to better understand the usage of the bulb and how it is related to time for a individual person. This can be later used to set Night Modes, Power Saver mode at some scheduled time that statifies the user's light pattern.

Power State Data Plot using Ubidots

Power State Data Plot using Ubidots