Postbox detector with SigFox Akeru board

The idea of this project is to easy detect if the postman has put some letter’s in the box … or not. Problem, i live in a apartment, 3th floor, no communication link can be established between my apartment and the mailbox, Wifi networks are not available, ISM 433mhz, 2.4ghz link don’t work, GSM consumption is to high … but SigFox Akeru board work like a charm, amazing for only 25mw of output power with a lot of concrete and metal around…

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First, i have create a callback function from the SigFox dashboard,  that can send me back a email when the message is reached by the sigfox network.


The arduino code:

Only 26 lignes , code pretty simple, that only send a value to sigfox once, when the board is powered up.


#include <SoftwareSerial.h>
#include “Akeru.h”

int led = 13;
int Value = 0;

void setup()
pinMode(led, OUTPUT);
digitalWrite(led, HIGH);
digitalWrite(led, LOW);

void loop()



Simple 1 or 2A battery.

Detection system ?:

That a good question, in fact i want to power the board only for 30 seconds (enough to send a message) when the letter come inside the box, a optical detecting system (ldr, ir …) can be good choice but consume some power … i try to find the best solution.