If you are an electronic lover or you modify cars, you may feel the problem with inadequate power with your Starter Battery. Because the battery is decided and fixed only for the default power requirements and when you apply additional Audio Systems, Lights, Cameras Security Systems and applications like refrigerators, you have to use extra power.

Then how you apply an additional battery for your electronic components?

If you connect directly the 2nd battery to the Starter battery, the problem is, when 2nd battery dry out 2nd battery will be charged by Starter Battery. Even the engine power off that will happen. Bad effect is, your car will not start.

When applying a 2nd Battery following condition should be satisfied.

  1. Both batteries should be charged when car engine is on.
  2. Both batteries should be disconnected when the engine is off

To satisfy the above, we apply a unit call “Battery isolator”. There are two types of solenoids

  • Diode isolator

    1. Relay isolator

      1. 01. Diode isolators are commonly used. This unit is with two high current diodes. But the biggest disadvantage is, voltage drop due to the diodes and you have to change the Alternator Wiring.

        02.   Relay isolator or Voltage Sensitive Relay (VSR) is operated with a relay, when the engine is started the voltage goes higher than the normal voltage, then the voltage level is detected by the circuit and switch on the relay. This system is the most efficient system than diodes.

        Initially you have to find one of above isolators and if you purchase one it will be around USD 23 or more. Therefore, if you follow the following lesion, you can make one Voltage Sensitive Relay unit less than USD 5.

        This unit is better for a device that the battery level is more than 13.9v when the engine is on.

        1 K (2W) Resistor – 01
        10k (1/4W) Resistor – 01
        12v (1W) Zenner Diode – 01
        1N4001 Diode - 02
        12v (80A) Automotive Relay – 01

        TIP 31C Transistors – 01

        Circuit Diagram is as follows.

        PCB design is as follows.


        Main Battery pin should be connected to the + pole of the Starter (Main) Battery
        2nd Battery pin should be connected to the + pole of the 2nd Battery
        GND pin should be properly grounded.

        If you connect the battery wires with VSR correctly, you can start the vehicle. Then you can see the indicator LED light up and start to charge the both batteries. Once the engine is off, VSR unit will stop the operation and the connection with both batteries will be disconnected.

        If you have any problem with VSR, put in the comments and the entire wiring system will be discussed in next lesson.

        Hi, This is easy mades again. If You have an apple iPhone, you may have a problem about the default ringing tones. When we hear the same ringing tone again and again it may be bored. But HOW to add a NEW ringing tone to apple iPhone?

        It may not simple as other mobile phones (but not difficult ether). However if you follow the following steps you can use any ringing tone to your iPhone device as your taste.


        Not like other phones, your apple device will only support .m4r file format as ringing tone. So shall we see how to do it.

        You have to install iTune software in your PC and register on it.

        STEP #1
        Download a software to convert audio in to m4r format. You can use the following link to download one of such converters. 

        STEP #2

        Select an audio file and deduce the duration in to not more than 15 seconds.

        STEP #3

        Convert the file in to M4R format using downloaded converter software.

        STEP #4

        Connect your iPhone to the PC and RUN iTune

        STEP #5

        Drag and drop m4r file in to “TONE” window at iTune

        STEP #6

        Now go to settings > Sounds then you can see your ringing tone


        If you have an apple iPhnoe you may already know that the buzziest button of the phone is “HOME” button. If you want to go back or undo, cancel etc. most of things are used this “HOME” button. Therefore there is a possibility to breakdown that button soon.

        To prevent from such terrible issue I am going to show you how to activate a virtual button in your iPhone without any additional software.

        This facility is available in the iPhone’s settings but it is not activated in default settings. If you follow the following steps you can enable that facility.

        STEP #1
        Go to SETTINGS

        STEP #2
        Click on GENERAL

        STEP #3
        Click on ACCESSIBILITY

        STEP #4
        Go to AccessiveTouch

        STEP #5
        Enable the AccessiveTouch Button

        Now you can see a virtual button is on the screen.

        If you want to, you can decide what activity should be activated when single touch, double touch and for long press.

        Now you HOME button is safe.

        Your comments are invaluable....

        If you have followed my previous projects, you may already have an idea about SSD and RTC modules. This is also a digital clock but small and also more user friendly. In my previous LED clock and SSD RTC clock, there was no time "UP" and time "Down' functions. and also a defect i notice in that project was, when we try to change the time we had to start it from zero. In this project i have rectified those errors and some improvements as well.

        Required parts
        I have used few parts for this project and also familiar with you.


        Read and understand pin-outs of the KXY-5461BS SSD. then you can buy SSD as same as or equal to  this SSD.

        Now you need to use RTC module, but I recommended to built it yourself . Circuit is given below.

        You can make it yourself having visited to my previous posts regarding RTC LED clock.

        Following circuit is the switch panel.

        Pin Connection of SSD with arduino is as follows.

        Connect wires as follows, then connect it with RTC module

        Complete project should be like below.

        Now you can upload codes. Link to download code is given below

        Once the code is uploaded you can see the exact time, then press MODE button. now you will see that the minutes numbers only shows and blink. press up or down to adjust minutes. 

        Change Hours - Press again mode button and use "up" or "down" buttons to adjust the time. Once the adjustment is over press again mode button, then time is set. 

        12/24 Hours - When time is run, press "Down" button to display 12/24 hours clock.

        I hope you have watch my previous post regarding SIM 800L ATcommands. It is the basic and important part to understanding the working of SIM 800L module. Now in easy mades shall we go for more advance part that to understand the way of applying this module in to practical.

        Watch before start the project

        You know we can sen SMS and read SMS using this module. Once we received a massage we can read it and also we can send any word(texts). That text massage facility can be used as a special command. If we can get that command filtering other text massages, we can use those as a pass-code to activate a device or to send another command. 1st we have to filter our sms which is to be taken as commands out of other SMSs. Then assign the massage to a variable . after having red the variable you can do you activity.

        Therefore, i change and made updates to sim800l Library. because sim 800l library can only get the massage details but we need only massage body. I will give you all the links at the end of this page.

        Wiring part is same as my previous lesson PART 01, If you have not read that lesson, please read it. Only deference is i have added an LED to pin number 12 of Arduino Uno board.

        Only for understanding I have added an LED if you want to operate AC device or any high volt device, you can add a relay instead of LED. I hope you know how to add a relay, but for beginners I have added that circuit below.

        Following are the pin connection

        If the wiring part is completed upload the codes

        Our code is like this, If you want to On the device you have to send "#ON" without comma and also if you want to off the device you have to send an sms as "#OFF". the # mark is the identity to understand this device it as a command to active arduino code. 

        If you read the code, you can make more improvements to this code.

        Download the coding file and library from the link given below.

              Click on following to download Library and codes


        If you have any doubt, please feel free to put a comment below.

        If you are an arduino lover, you may be interested to work with mobile phone connections. I have seen some project which are activate with SMS or voice commands. but most of project are used old mobile phones. 

        It is not easy to customize as our requirements. Therefore we can use GPRS module to make our own project as our wish. Most simplified and easiest way for a programmer is arduino platform. that is why i have used this SIM module with arduino. It  is not complicated. But there are more GPRS modules but I am using SIM800L module for this project.

        Watch for more Details

        Lets see the wiring as the wiring part is the most important part. It may be a cause to burn the device since a single mistake.

        It should be connected arduino with sim800L module according to the above and connection will be shown as follows.

        For more safety of the sim 800L module give the power to SIM800L module through Arduino Uno board through a diode as follows

        Fore more details read the following image as well

        If all the wiring connections are checked and confirmed as correct, go to arduino programme and do the coding. 

        before the coding you must identify the correct direction of the sim card. it is normally printed on the surface of the sim slot.

        To start coding, RUN arduino software.

        Once the coding is uploaded, go to TOOLS > SERIAL MONITOR then, change the settings as follows

        Now it is ready to check "AT" Commands.
        Before check AT commands we have to check this module is working. Therefore you can take a phone call dialing the number of the sim using another sim. If you can hear the dialing tone, then your module is ready to work.

        Now, Type AT in serial monitor and press ENTER, then serial monitor should display as OK. Then you can check with thousands of AT commands and learn how to work with sim800L module.

        Click on following to download AT command list

        Click on following to download the arduino  file

        Arduino Code

        SoftwareSerial Sim800l(10,11);
        void setup() {
          // put your setup code here, to run once:
        void loop() {
        If you have any clarifications, comments about this project 
        please feel free to put a comment below.
        Copyright © 2013 Easy Mades