Add logging to your project for about $5

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A VPN is an essential component of IT security, whether you’re just starting a business or are already up and running. Most business interactions and transactions happen online and VPN

A inexpensive way to start logging data from your sensors is with a SD Card. Although some shields come with onboard SD Slots, if you don’t have one you can add it to your project for about $5

https://amzn.to/2WJh7w5

This board is 5v & 3.3v friendly.

Examples and instructions for reading and writing to SD Cards can be found at http://arduino.cc/en/Reference/SD

Connections:

SD UNO MEGA
CS 4 53
MOSI 11 51
SCK 13 52
MISO 12 50

Stay tuned for a number of upcoming SD Card logging projects!
Code:

/*
  SD card datalogger

 This example shows how to log data from three analog sensors
 to an SD card using the SD library.

 The circuit:
 * analog sensors on analog ins 0, 1, and 2
 * SD card attached to SPI bus as follows:
 ** MOSI – pin 11
 ** MISO – pin 12
 ** CLK – pin 13
 ** CS – pin 4

 created  24 Nov 2010
 modified 9 Apr 2012
 by Tom Igoe

 This example code is in the public domain.

 */

#include <SPI.h>
#include <SD.h>

// On the Ethernet Shield, CS is pin 4. Note that even if it’s not
// used as the CS pin, the hardware CS pin (10 on most Arduino boards,
// 53 on the Mega) must be left as an output or the SD library
// functions will not work.
const int chipSelect = 4;

void setup()
{
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
// wait for serial port to connect. Needed for Leonardo only
}

Serial.print(“Initializing SD card…”);
// make sure that the default chip select pin is set to
// output, even if you don’t use it:
pinMode(10, OUTPUT);

// see if the card is present and can be initialized:
if (!SD.begin(chipSelect)) {
Serial.println(“Card failed, or not present”);
// don’t do anything more:
return;
}
Serial.println(“card initialized.”);
}

void loop()
{
// make a string for assembling the data to log:
String dataString = “”;

// read three sensors and append to the string:
for (int analogPin = 0; analogPin < 3; analogPin++) {
int sensor = analogRead(analogPin);
dataString += String(sensor);
if (analogPin < 2) {
dataString += “,”;
}
}

// open the file. note that only one file can be open at a time,
// so you have to close this one before opening another.
File dataFile = SD.open(“datalog.txt”, FILE_WRITE);

// if the file is available, write to it:
if (dataFile) {
dataFile.println(dataString);
dataFile.close();
// print to the serial port too:
Serial.println(dataString);
}
// if the file isn’t open, pop up an error:
else {
Serial.println(“error opening datalog.txt”);
}
}


Steve Spence

Steve Spence

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