Sigfox Doorbell Posting Message on Slack

It all came from a challenge made by Nicolas Lesconnec on Twitter to add Sigfox connectivity to Konstantin Dimitrov's great project: Arduino Capacitive Sensor In less Than 2 Minutes.

So, I decided to give it a go!

But it is useless to just add connectivity to a project. Hopefully (or not) our door broke yesterday on the 4th floor, thus, I decided to make a doorbell that posts a message on Slack.

The base of the project is the same than the Arduino Capacitive Sensor In Less Than 2 Minutes, I just changed from an Arduino to an Akeru board, which has the same Atmega processor but has the Sigfox module included.

You just need:

1 x Akeru board
1 x 1M resistor
1 x Coin (or any conductive material)
1 x LED
4 x Jumpers
1 x Cardboard box (I used a Sparkfun Kit's box)

Just plug the 1M resistor between the D2 and D8 pins

First, you need to download the following library and import them under the Arduino's library repository:

• https://github.com/PaulStoffregen/CapacitiveSensor
• https://github.com/Snootlab/Akeru

Now create a new sketch and copy/past or clone the code:

https://github.com/luisomoreau/sigfox_doorbell

#include <Akeru.h>
#include <CapacitiveSensor.h>

// TD1208 Sigfox module IO definition
/*   Snootlab device | TX | RX
               Akeru | D4 | D5
               Akene | D5 | D4
            Breakout | your pick */
#define TX 4
#define RX 5

// Sigfox instance management 
Akeru akeru(RX, TX);


//Capacitive sensor
CapacitiveSensor   cs = CapacitiveSensor(2,8); // 1M resistor between pins 2 & 8, pin 8 is sensor pin, add a wire and or foil


//Global variable
bool flag = true;

void setup()                    
{
   cs.set_CS_AutocaL_Millis(0xFFFFFFFF);// turn off autocalibrate on channel 1 - just as an example
   //Serial.begin(9600);
   
   pinMode(7,OUTPUT);

   //Serial.println("Starting...");

   if (!akeru.begin())
  {
    //Serial.println("TD1208 KO");
    while(1);
  }else{
    //Serial.println("Ready!!");
  }
}

void loop()                    
{
   long sensor =  cs.capacitiveSensor(50);

   //Serial.println(sensor1);  // print sensor output 
   if(sensor >= 1000)
   {
    digitalWrite(7,HIGH);
    if(flag){
      sendMessage();
    }
    }
   else{
    digitalWrite(7,LOW);
   }  
}

void sendMessage(){
    flag = false;
    //Serial.println("Sending...");
    if (akeru.sendPayload("01"))
    {
      //Serial.println("Message sent !");
      
    }
    delay(1000);
    flag = true;
  
}

You can try to run the code, every time the coin is touched, it will trigger a Sigfox message.

Be careful to the duty cycle limit. This depends on your region's regulation.

Learn more on http://makers.sigfox.com/

Activate your device

If you don't know how to activate your device, I wrote a small tutorial few month ago on http://blog.sigfox.com/activate-dev-kits/

Create a Slack WebHook

In order to post your message on slack, go to your slack's team and create a new incoming WebHook:

https://[your-team].slack.com/apps or search for Incoming WebHook

Click on "Create a new configuration"

Follow the form and copy the given webhook link

Create a Sigfox custom callback

Now go to your device type in Sigfox Backend (https://backend.sigfox.com) and click on Callbacks.

Click on "New"

Past the incoming webhook and add your JSON:

{
"text": "Hey!! Someone is stuck at the door... could anyone open the 4th floor door? thank you :)"
}

Now every time a sigfox message is sent, a message will be post by your Slack bot.

I would be glad to answer your question.

Thank you for your attention.