<p><img src="http://yapelesolutions.co.za/mine/current1.png" align="middle"></p>
<p>This is an UPDATE for <a href="https://steemit.com/technology/@mokluc/my-arduino-fun-projects-part1-electricity-data-logging-system">My Arduino fun projects: Part1: Electricity data logging system</a> </p>
<p>The update was request by <a href="https://steemit.com/@blocktrades">@blocktrades</a>
 to grow the “Arduino” tag on Steemit.</p>
<p><img src="https://picload.org/image/rdladoal/blocktrades.jpg" align="middle"></p>
<p>Comments can be found on my other blog (which will also be updated to include all the coding and schematics): <a href="https://steemit.com/technology/@mokluc/my-arduino-fun-projects-part2-fingerprint-scanner-which-enrols-and-authenticate-users-then-takes-a-picture-and-uploads-it-to">My Arduino fun projects: Part2: Fingerprint scanner which enrolls and authenticate users then takes a picture and uploads it to Dropbox</a> </p>
<hr>
<p>I will breakdown the project into fewer parts and conclude by combining all the parts as a final design.</p>
<h4>Parts to be discussed:</h4>
<ul style="list-style-type:square">
<li>ATMega328P-PU</li> 
<li>FTDI</li> 
<li>Real Time Clock (RTC)</li>
<li>Current clamp</li> 
<li>SD card module for data logging.</li> 
<li>Final design</li> 
</ul>

<hr>
<h3>ATMega328P-PU</h3>
<p><img src="https://picload.org/image/rdladaga/atmega.png" align="middle"></p>
<p>ATMega328P-PU to Arduino pinout.</p>
<p>ATMega328P-PU, a low-power version of the traditional ATMega328-PU was taken from an Arduino Uno with a pre-burned boot loader.</p>
<hr>

<h3>FTDI</h3>
<p><img src="https://picload.org/image/rdlaggcg/ftdi.png" align="middle"></p>
<p>SparkFun FDTI breakout module.</p>
<p>FTDI uses an FT232RL IC to convert USB signals to UART signals (serial communication).</p>
<p><img src="https://picload.org/image/rdlagrda/ftditable.png" align="middle"></p>
<h4>Wiring:</h4>
<p><img src="https://picload.org/image/rdlagoir/ftdicon.png" align="middle"></p>
<p>The above circuit can also be used to program the ATMega directly from Arduino IDE using the FTDI.</p>
<h4>More information and drivers:</h4> 
<p><a href="https://learn.sparkfun.com/tutorials/how-to-install-ftdi-drivers">https://learn.sparkfun.com/tutorials/how-to-install-ftdi-drivers</a></p>
<hr>
<h3>Real Time Clock (RTC)</h3>
<p><img src="https://picload.org/image/rdlagdpl/rtc.png" align="middle"></p>
<p>RTC breakout module</p>
<p>RTC is built around DS1307 IC with an external 32.768 kHz crystal and communicates with the ATMega (Arduino) through Inter-Integrated Circuit (I²C) protocol. RTC has a built-in power-sense circuit that detects power failures and automatically switches to the backup supply (coin battery) to continue keeping time.</p>
<h4>Wiring:</h4>
<p><img src="https://picload.org/image/rdladoiw/rtccon.jpg" align="middle"></p>
<h4>Code:</h4>
<p><img src="https://picload.org/image/rdlagldg/rtcprog.png" align="middle"></p>
<p>Please note I have modified the example code to give me time and date as: day/month/year hour:minutes:seconds (e.g. 19/10/2016 14:00:00)</p>
<h4>More information:</h4> 
<p><a href="https://learn.adafruit.com/ds1307-real-time-clock-breakout-board-kit/overview">https://learn.adafruit.com/ds1307-real-time-clock-breakout-board-kit/overview</a></p>
<hr>

<h3>Current clamp</h3>
<p><img src="https://picload.org/image/rdlagccc/clamp.png" align="middle"></p>
<p>I used the YHDC SCT-013-000 with an input current: 100 A as seen below.</p>
<p><img src="https://picload.org/image/rdlagcgi/ctdatasheet.png" align="middle"></p>
<h4>Wiring and operation:</h4>
<p><img src="https://openenergymonitor.org/emon/sites/default/files/Arduino%20AC%20current%20input%20A.png" align="middle"></p>
<p>Image credit: openenergymonitor.org</p>
<p>Detailed operation and calculations are <a href="https://openenergymonitor.org/emon/buildingblocks/ct-sensors-interface">here</a> </p>
<h4>Code:</h4>
<p><img src="https://picload.org/image/rdlagiwp/currentprog.png" align="middle"></p>
<p>Please note in South Africa we use <b>220-230 VAC at 50-60 Hz</b>, so kindly read  <a href="https://openenergymonitor.org/emon/buildingblocks/ct-sensors-interface"> operation and calculations</a> to calibrate for correct readings.</p>
<h4>Results:</h4> 
<p><img src="https://picload.org/image/rdlagwwd/results.png" align="middle"></p>
<hr>

<h3>SD card</h3>
<p><img src="https://picload.org/image/rdlargcl/sd.png" align="middle"></p>
<p>SD card breakout board</p>
<p>SD cards are popular for storing files and photos and widely used in almost every mobile device. SD card breakout board communicates with the ATMega (Arduino) through Serial Peripheral Interface (SPI) protocol. </p>
<h4>Wiring:</h4>
<p><img src="https://picload.org/image/rdlaroga/sdcon.png" align="middle"></p>

<h4>Code:</h4>
<p>The SD library comes with the Arduino IDE. It needs to be included at the beginning of the sketch.</p>
<p><img src="https://picload.org/image/rdlarodo/sdlib.png" align="middle"></p>
<p>Including `SD.h` automatically creates a global “SD” object which can be interacted within a similar manner to other standard global objects like “Serial”.</p>
<h4>To “read” from SD card, first open the file:</h4>
<p><img src="https://picload.org/image/rdlarlcl/sdopen.png" align="middle"></p>
<p>It will return false if it fails to open the file, so check dataFile before using it. The “read” function reads the file line by line, so will have to use a while loop, until it fails to reach the end of the file. </p>
<h4>To “Write” to SD card:</h4>
<p>First open the file to write to with “FILE_WRITE” parameter.</p>
<p><img src="https://picload.org/image/rdlarccr/sdopen2.png" align="middle"></p>
<p>The “open” function takes two parameters, file location and mode (only required for “Write”, if missing by default it opens the file in Read-Only mode).</p>
<p>It will return false if it fails to open the file, so check dataFile before using it and can write to the file using the following:</p>
<p><img src="https://picload.org/image/rdlarccd/sddatafile.png" align="middle"></p>
<p>Close the file after writing to it and open one file at a time.</p>
<h4>Check if a File Exists:</h4>
<p><img src="https://picload.org/image/rdlarccp/sdexists.png" align="middle"></p>
<h4>Create a Text/Excel File on SD Card:</h4>
<p>There is not a function for this purposes, but you can open a file with “FILE_WRITE” mode to create a file, if this file does not exist.</p>
<p><img src="https://picload.org/image/rdlarccw/sdwrite.png" align="middle"></p>
<p>Please note name.csv its Excel file and name.txt its normal text file.</p>
<p><img src="https://picload.org/image/rdlarcig/sdfinal.png" align="middle"></p>
<hr>
<h3>Final design</h3> 
<p><img src="https://picload.org/image/rdlagpip/schematicmain.png" align="middle"></p>
<h4>Final sketch:</h4>
<p>Final coding is just combination of all the codes explained above. Note I do not discuss the LED blink rate and percentage change as they are optional but I have included them on the final sketch.</p>

<h2>The full Arduino sketch is very long so I uploaded it on <a href="https://github.com/Yapele/Electricity-data-logging-system">Github</a> </h2>
<h2>Feel free to use it and have fun with it</h2>
<p>Kindly upvote and follow me: <a href="https://steemit.com/@mokluc">@mokluc</a>….I will upload another project soon: <b>My Arduino fun projects<b></p>