MPL3115A2 sensor (GCC), Linux MySQL/postgreSQL

MPL3115A2 (Language C) Linux MySQL (Banana Pi/Raspberry Pi)

The MPL3115A2 is a compact piezoresistive absolute pressure sensor with an I2C interface. MPL3115A2 has a wide operating range of 20 kPa to 110 kPa, a range that covers all surface elevations on earth. The fully internally compensated MEMS in conjunction with an embedded high resolution 24-bit equivalent ADC provide accurate pressure (Pascals)/altitude (meters) and temperature (°C) data.(see DataSheet, AN4481, AN4519)

Direct reading:

— Pressure: 20-bit measurement (Pascals)
— Altitude: 20-bit measurement (meters)
— Temperature: 12-bit measurement (°C)

MPL3115A2

Simple test MPL3115A2 with a BananaPi. Using the I2C library functions (WiringPi), we communicate with the sensor, then the data is stored in MySQL/postgreSQL database.


CREATE DATABASE sensor;

CREATE TABLE sensor.samples(
 sampleId INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
 sampleDate DATE,
 sampleTime TIME,
 sampleTemperature DOUBLE,
 sampleAltitude DOUBLE,
 samplePressure DOUBLE) default character  set utf8;

Download source code

   MYSQL *conn;
   MYSQL_RES *res;
   //MYSQL_ROW fila;

   char *server = "localhost";
   char *user = "sydbernard";
   char *password = "secreto";
   char *database = "sensor";
   
   conn = mysql_init(NULL);
   
   // Connect to database //
   if (!mysql_real_connect(conn, server,
         user, password, database, 0, NULL, 0)) {
      fprintf(stderr, "%s\n", mysql_error(conn));
      exit(1);
   }

   ...

   /* send SQL query */
   if (mysql_query(conn, buffer)) {
       fprintf(stderr, "%s\n", mysql_error(conn));
       exit(1);
   }
    

To Compile:

$ gcc -Wall -c main.c MPL3115A2.c
$ gcc -Wall -o mpl main.o MPL3115A2.o -l wiringPi -lmysqlclient

wiringBPi

Table MySQL

MySQL

PostgreSQL

PostgreSQL is an object-relational SQL database management system.

Header files and static library for compiling C programs to link with the libpq library in order to communicate with a PostgreSQL database backend.

sudo apt-get install libpq-dev
____________________________

create table samples(
 sampleId SERIAL PRIMARY KEY,
 sampleTemperature DOUBLE precision,
 sampleAltitude DOUBLE precision,
 samplePressure DOUBLE precision

);

PGresult *res;
PGconn *pgConn = PQconnectdb("dbname=sensor hostaddr=127.0.0.1 \
                               user=sydbernard password=snoopy");
if (PQstatus(pgConn) != CONNECTION_OK)
{
   fprintf(stderr, "Connection to database failed: %s",
   PQerrorMessage(pgConn));
}

...

sprintf(buffer,"INSERT INTO samples (sampleTemperature,sampleAltitude,samplePressure) \
VALUES (%.2f, %.2f, %.2f);",temperature, altitude, pressure);

/* send SQL query */
res = PQexec(pgConn, buffer);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
 fprintf(stderr, ">%s", PQerrorMessage(pgConn));
 PQclear(res);
       
}

Source Code Download

postgreSQL