“ST Connect is an autonomous connected object that collect and send data, in order to monitore dikes in the Barcellonette. #PolytechSorbonne
Story
Introduction
During our studies at Polytech Sorbonne in 2018, Earth Science teachers needed to monitor dikes in the Barcelonnette, a municipality of France in the south of the Alps. They asked us to find a solution to collect regularly data such as ground and air temperature and humidity, pressure and magnetic field in order to detect landslide.
We chose to design an autonomous connecting object that send data they need on a website, where it will be available to consult on. This object will be put on dikes, and it has to works without human interaction except a single visit per year.
Specifications
As Earth teachers tell us, to monitor dikes, they need to be able to consult 6 physical measures :
Air temperature
Air humidity
Ground temperature
Ground humidity
Local magnetic field
Pressure variations (to detect altitude variations)
We will use sensors to get data and a communication module to send it on a website. In order to do that, we will use a microcontroller to manage sensors and communications.
Dikes monitoring requires regular data, optimally, every minute, but in our case Earth teachers asked us to send data every 10 minutes.
Our object has to be energy self sufficient, because it will be put on the dike and has to work during a year without human interaction. Even if we can use an efficient battery, we have to charge it regularly if we want it to work during a year. Due to all these constraints, we have to design our object with:
An efficient battery
A solar panel
Sensors, communication module and a low consuming microcontroller (in sleep mode)
Moreover, if we want our object to work a whole year, it has to be solid (to resist to a rock fall) and be waterproof, in order to protect the electronic circuits inside of the box. After some researches, we decided to certify our object IP54S that correspond to a total protection to dust, a protection to water projections and a resistance to 1J shocks.
SigFox
Sigfox network allows us to send 140 messages per day, so we chose to send a message every 12 minutes (120 message per day).”