What is NMF Atlantis
Why this project
How does it work
You are now able to monitor any waterway and save lives

Team NMF Atlantis: Emmanuel Collin, Théo Paillier, René - Mervis MUDRY, meriem lagha

Published January 20, 2020 © GPL3+

NMF Atlantis

Flood detection system through water level measurements. Data transmission using Sigfox LPWAN. Real-time monitoring and alerts on Ubidots.

AdvancedShowcase (no instructions)24 hours817

Things used in this project

Hardware components

ST STM32L4, STM32F7 Nucleo 144 STM32F7

DHT22 Temperature Sensor

Sigfox Breakout board BRKWS01

Seeed Studio Grove - Ultrasonic Ranger

3.7V 1050mAh LiPo Battery

2W Solar Panel

Plastic Enclosure, Proj box

Resistor 10k ohm

Resistor 2.21k ohm

Pololu S7V8F5

Capacitor 4.7 µF

MCP73831 Single Cell, Li-Ion/Li-Polymer Charge Management Controller

Software apps and online services

Solidworks

Hand tools and fabrication machines

Soldering iron (generic)

Solder Wire, Lead Free

3D Printer (generic)

Hot glue gun (generic)

10 Pc. Jumper Wire Kit, 5 cm Long

Wire Stripper & Cutter, 18-10 AWG / 0.75-4mm² Capacity Wires

Story

What is NMF Atlantis ?

NMF Atlantis is an embedded system that aims to warn users of an incoming flood so they can prepare and get safe before it happens. It is a student project realised at Polytech Sorbonne.

Why this project?

Floods are an increasing threat because of the rise of the sea level. They are occuring more frequently and their damage are tremendous. The point of this project is to warn people soon enough so they are prepared when the flood arises. This way, lives will be saved and some damage might get avoided.

How does it work?

The core of our system is the microcontroller that is running the program and that is connected to all the sensors, the battery and the Sigfox module. Using a Low-Power Wide-Area Network (Sigfox's LPWAN) and a rechargeable power supply were the specifications ventured by our teachers. Therefore, we focused on reducing the power consumption. In order to do that and yet having a reliable product, the program is carrying on measurements every 15 minutes and send the results every hour (default settings).

1 / 2 • General aspect

With the support of our teachers, we managed to achieve our goal and create an automous device able to warn users of a potential flood as well as giving them details about temperature and humidity.

Main features:

Level measurement,
Temperature measurement,
Humidity measurement,
LPWAN data sending,
Fully autonomous.

Code

We wanted the code to be easily adaptable to a local situation. Therefore, five variables rule the program operation. Those five variables are:

// Depending on the waterway
float sensor_limit = 4.0*100.0;
float danger_limit = 50.0;
int danger_time = 15;
int default_time = 30;
int sending_interval = 3600; //every hour (1h = 3600 s).

The first limit (sensor_limit) indicates the reach of the rangefinder used. The second limit is the danger_limit and as to be set according the threat of the waterway you are willing to monitor. The danger_time and default_time are the intervals between two measurements in case of danger or by default. Finally, the sending_interval indicates the time between two messages. You will find the whole code in the Attachments or by clicking on the following link.

Electronic

The STM32 Nucleo-L432KC development board has to be linked with the sensors following the schematic below. The Power Supply has its own circuit (that can be found below as well). The main purpose of this circuit is to recharge the Li-Ion battery thanks to a solar panel and a charge manager, the MCP73831. The second purpose is to retrieve the battery level and send it to one of the microcontroller pins.

1 / 2 • Microcontroller, sensors and Sigfox module wiring plans

Feel free to plan the pins the way it suits you. However, do not forget to modify the code so the microcontroller take it into account.

To make the wiring more reliable, we designed Printed Circuit Board for both the microcontroller and its sensors and the power supply. The KiCad files are available in the attachments.

1 / 2 • Power Supply PCB design

Data Processing

Data is sent through a 10-bit bus:

4 bits for the distance,
2 bits for the temperature,
2 bits for the humidity,
2 bits for the battery level.

Then, callbacks have to be configure on the Sigfox backend platform:

Callbacks settings

The data received is not representative of the reality yet. Two synthetic variables are needed :

Vbat = (vreduced*3.3*2/100)/3.7*100the battery voltage,
Temperature = temperature-40the real temperature.

Next step is to configure your Ubidots dashboard to make it look the way you want. You will also be able to configure on what level an alert is sent to your mail box or phone.

Ubidots dashboard example

You are now able to monitor any waterway and save lives!

About the name: NMF stands for No More Flood and Atlantis is an obvious reference to the mythicalsubmerged city.

Schematics

Code

Main

#include "mbed.h"
#include "DHT.h"
#include "Pulse.h"
#include "RangeFinder.h"
#include "WakeUp.h"


RangeFinder rf(D12, 10, 5800, 100000); //(Pin, duree du pulse en us, distance [m] = pulse width [us] / 5800 [us / m] , temps de fonctionnement)

DigitalOut led(LED1);
Serial serial(D1, D0);
Serial pc(USBTX, USBRX);
DHT HTSensor(D10,22);
AnalogIn battery(A1);


int main()
{

    pc.printf("Starting...\n\r\n\r");

    float d;
    int dInt;
    
    float temperature;
    int tInt;
    float humidity;
    int hInt;
    float b;
    int bInt;
    int cpt = 0;
  
      
    // En fonction du cours d'eau
    float Limite_sensor = 4.0*100.0;
    float Limite_danger = 50.0; 
    int Temps_danger = 900; 
    int Temps_default = 1800;
    int Intervalle_envoi = 3600; //Toutes les heures (1h = 3600 s)
    while (1)   
    {   
        //Mesure niveau batterie réduite (entre 0 V et 1.85 V) 
        b = battery.read()*3.3f;
        bInt = (int)(b*100/3.3f);
        
        pc.printf("Voltage = %f volts\r\n\r\n", b);
        pc.printf("Voltage code = %d percentage\r\n\r\n", bInt);
                 
        //Mesures de temperature et humidite
        
        HTSensor.readData();
        wait_us(500);
        
        temperature = HTSensor.ReadTemperature(KELVIN) - 273,15;
        tInt = (int) (temperature + 40);
        humidity = HTSensor.ReadHumidity();
        hInt = (int) humidity;
        
        
        pc.printf("Temperature = %f degre C.\n\r", temperature);
        pc.printf("temp code = %d\n\r", tInt);
        pc.printf("temp Hex = %02x\n\r\n\r",tInt);
        pc.printf("Humidity = %f percentage.\n\r", humidity);
        pc.printf("hum code = %d\n\r", hInt);
        pc.printf("hum Hex = %02x\n\r\n\r",hInt);
        
        //Mesure distance
        
        d = rf.read_m();
        d = d*100;
        if (d < 0)  
        {
            d = 0;
            WakeUp::set(Temps_default); //temps en secondes
            deepsleep();
            cpt += Temps_default; 

        } 
        else if (d >= Limite_sensor) 
        {
            d = Limite_sensor;
            
            // Seeed's sensor has a maximum range of 4m, it returns
            // something like 7m if the ultrasound pulse isn't reflected.
            WakeUp::set(Temps_default); //temps en secondes
            deepsleep();
            cpt += Temps_default; 
        }
        else if (d <= Limite_danger) // Flood
        {
            dInt = (int)d;
            
            //Envoi des informations
            serial.printf("AT$SF=%04x%02x%02x%02x\r\n",dInt,tInt,hInt, bInt);
          
            //Si danger, on l'envoie à chaque fois
            WakeUp::set(Temps_danger); //Temps en secondes
            deepsleep();
            cpt += Temps_danger;
        }
        else
        {
            
            WakeUp::set(Temps_default); //temps en secondes
            deepsleep();
            cpt += Temps_default;
        }
        
        if (cpt >= Intervalle_envoi)
        {
            dInt = (int)d;
            serial.printf("AT$SF=%04x%02x%02x%02x\r\n",dInt,tInt,hInt, bInt);
            cpt = 0;
        }

    }
}

NMF Atlantis