Published January 9, 2017 © CC BY

Echo Kill Switch

Use Amazon Alexa to trigger an IFTTT applet that causes a Particle Photon to remove power from an Echo.

BeginnerFull instructions provided2 hours12,119

Things used in this project

Hardware components

Particle Photon

Amazon Alexa Echo Dot

Breadboard (generic)

N-Channel MOSFET

Pushbutton 12mm

LED (generic)

Resistor 1M ohm

Resistor 100 ohm

Resistor 10k ohm

Resistor 1k ohm

Jumper wires (generic)

SparkFun microB USB Breakout

USB Type A Female Breakout

USB-A to Micro-USB Cable

Software apps and online services

IFTTT Amazon Alexa service

Story

Many people have expressed concerns about the privacy implications of IoT devices, like the XBox Kinect and Amazon Echo, that are always listening and potentially recording everything it hears. Recently, a warrant was issued to Amazon to release any audio recordings of one particular Echo device that was present (and possibly listening) at the scene of a murder.

While I enjoy being able to talk to my Echo, I know that security and privacy are paramount for many. To remedy the "always-on" nature of the Echo (and other USB-powered IoT devices), I created a kill switch that is activated over IFTTT and created a set of instructions below so you, too, can make your own!

Step 1: Construct Hardware

We'll do this on a breadboard. Feel free to solder everything together on a protoboard to make it more permanent.

Step 2: Program the Photon

Connect the Photon to the Internet as per these steps. Log in to the Particle IDE and copy in the code from the Code section. Upload the program to the Photon.

Step 3: Set Up IFTTT Applet

Navigate to IFTTT, and create an account (if you don't already have one). Create a new applet. Search for "Alexa" and connect your Amazon account. For the THIS part, choose Say a specific phrase under Alexa.

Type in the trigger phrase, such as "kill switch" (or anything else you want to tell Alexa to cut power to the Echo). Just remember that you'll need to say "Alexa, trigger <your phrase>" to use IFTTT from Alexa.

For the IFTTT THAT portion, search for "Particle," connect your Particle account, and choose Call a function.

Select the function killSwitch on "<your Photon>" and enter off for with input.

Click Create action, and that's all! You're now ready to kill your Echo with your voice.

Step 4: Try It

Connect a USB cable from a wall adapter to the USB micro port on the breadboard. Connect another cable from the USB Type-A port on the breadboard to the Echo. Once the Photon powers up, press the button to turn the Echo on.

Wait for the Echo to connect to the Internet, and then say "Alexa, trigger kill switch" (or whatever phrase you put into IFTTT). Alexa should call your IFTTT applet, which should send a command to the Photon to disable power to the Echo. You'll need to push the button on the breadboard to turn the Echo back on (or set up another IFTTT applet so you can enable it from your phone).

Code

Echo Kill Switch Particle Code

// Kill switch for Amazon Echo

int kill_switch = D5;
int button = D6;
int btn_prev_state = HIGH;

void setup() {
    
    // Switch is output, button is input
    pinMode(kill_switch, OUTPUT);
    pinMode(button, INPUT);
    
    // Initialize kill switch as default low
    digitalWrite(kill_switch, LOW);
    
    // Register a cloud function
    Particle.function("killSwitch", killSwitch);
}

void loop() {
    
    // If button is pushed, toggle kill switch
    int btn_state = digitalRead(button);
    if ( (btn_state == LOW) && (btn_prev_state == HIGH) ) {
        digitalWrite(kill_switch, !digitalRead(kill_switch));
    }
    btn_prev_state = btn_state;
}

int killSwitch(String state) {
    
    // Set pin state based on given parameters
    if ( state == "on" ) {
        digitalWrite(kill_switch, HIGH);
    } else if ( state == "off" ) {
        digitalWrite(kill_switch, LOW);
    } else {
        return -1;
    }
    
    return 0;
}