CONTROLL YOUR DOORS LATCH WITH CELPHONE

I’ve been reading a lot on how DTMF (Dual Tone Multi Frequency) tones work over the last couple of weeks. I’m sure you’ve noticed that when you press the keys on a standard telephone keypad, an audible ‘beep’ is generated. These beeps are actually the combination of two distinct frequencies. For example, the tone you hear when you press the number ‘9’ on a telephone, is actually a combination of a 1447 Hz and 852 Hz signal. In a telephone exchange, these signals are decoded by a computer which finally connects the dialer to the designated phone line. For example, the tone of 1447 Hz and 852 Hz will be decoded as binary ‘1001’. In this project, I have designed a simple DTMF decoder circuit which allows me to control appliances in my house from any place on Earth using a telephone.

I always wanted to be able to control things such as air-conditioners, lights, etc, remotely…but I never thought about putting the front door of my house under remote control until I saw this “knock to open” door hack on Hackaday. It’s a door that will unlock when the correct knock pattern is performed. After being inspired by the mechanical door opening system in that hack, I decided to do something similar to allow me to open my door with a cell phone! I mean c’mon, door locks with keys are obsolete..everyone uses them..they’re so old fashioned! They’ve been around for over 4,000 years. Yikes! It’s time for a little change.

This project would have been much simpler if I had an electronic door lock…but I didn’t! They’re expensive, so I didn’t want to buy a new electronic door lock. I wanted to open the front door of my house without “seriously” modifying/replacing any door components. I thought about using a servo/stepper motor to twist the door knob on the door, but their control circuitry is slightly complicated if you’re not using a microcontroller. So, I decided to use a simple, 24VDC, “pull solenoid”. They don’t have any complicated control circuitry and you just have to supply the required voltage to make them work. I simply fastened the solenoid to the door knob with a metal wire. When the solenoid is switched on, its linear motion twists the door knob and opens the door. Positioning the solenoid properly was probably the only mechanical challenge in building this door opener because the force applied by a solenoid, is theoretically inversely proportional the square of the length of the air gap. Thus, strongest force is generated when the air gap is smallest.

The second part of this project was to build a DTMF decoder circuit. I used a CM8870PI tone decoder IC for doing this. The circuit I have built is fairly simple, and can be used for controlling up to four devices. If you want to control more than four devices, check out this circuit. I had a Nokia 1100 cell phone lying around with a hands-free accessory which was rarely used. So, I hacked its hands-free accessory and connected it to the circuit (I just cut the wires which went into the earpiece). That’s about it! To control things in the house, you just dial into the base station and the Nokia 1100 auto-answers the phone call. Each function is just a matter of pressing the appropriate number on the phone and the DTMF chip decodes it and sends output to a transistor which controls a relay. To open my door, I just dial the phone, enter the magic code and voila - Alohomora! Watch the video above. :)
Now I’m thinking about building a password protected door by placing a keypad outside my house which will generate DTMF tones. A circuit on the other side of the door will check the numbers entered, and if the password is correct, it will open the door. However, there’s one little snag. Any nasty programmer would just love to use a computer to generate DTMF tones and crack the password using brute force…I would. :)


     YOU CAN DO MORE FROM THIS GUY'S JUST THINK DIFFERENT AND INOVATIVE

Hey guy's , In this blog i am gonna show you how to make simple and cheap single channel audio amp in just few step's :-

here's a previous priview:-

i will show you how to build an Audio amplifier based on LM386 IC. The circuit is very simple and construction is easy on a breadboard. The LM386 IC is unique in that the gain can be modified by changing Resistor R2 and Capacitor C2. This configuration will give us a gain of 20. By removing R2 and connecting C2 across pins 1 and 8, we can increase the gain to 200. It is important to understand that increasing the gain does not increase the output power. The increased gain is only used when a very low input signal is to be amplified. In a previous article I discussed building audio amplifiers using discrete transistors. While it is possible to build good audio amplifiers from discrete transistors, they are no match for the many audio amp IC's available to us. IC's offer many advantages including high efficiency, high gain, low standby current, low component count, small size and ,of course, low cost. It is little wonder that audio amp IC's have replaced discrete transistors in most consumer electronic devices. While many experimenters have stayed away from these little black mysteries, I am going to uncover some of their secrets and demonstrate how easy they are to use.

The Lm386 milti purpose amp, can be used with audio devices, guitars etc :

WARNING -
do not connect to above 12v dc supply but use less ampere rating if you are using 12v or i will preffer you to use an 9v dc battery or a regulated dc power source for it , the lm386  may blow up  if you excede the voltage source  !!!

step1:-

Gather these part's from your near electronic market or shop!!!!
parts for this circuit:-

1. LM386 IC
2. 10K POT
3. 220uF CAP
4. 10uF CAP
5. 100uF CAP
6. 0.047uF CAP
7. AUDIO MALE FEMALE JACKS AS PER REQUIREMENT !!
8. AUDIO CABLE
9. genera pcb or bread board which you like more it's your choice!!!

step2:-

this is the circuit for the amplifier:-

 I've arranged the speakers from a old amp which has broken and also it was old to

1. They are loud enough but after a certain amount of amplification they start to distort.
2. it would be better if you use bigger and more powerful speaker but should not exceed the power rating max 2w speakers

           MAKE IT LOVE IT HAVE FUN GUY'S

friend's i hope you like this project and if you have any query related to this project so feel free to ask question , you can comment or if you shy to comment   so mail me  <<*_*>>


************_______THANK U GUY'S FOR WATCHING MY Blog_______***********

                
Hey, guys in this blog i am gonna show you " HOW TO MAKE A SIMPLE  STATIC  ELETRICITY DETECTOR "

But first read this that what is static electricity and what is normal electricity!!
for your clearance!!!!

        *___Now you know what is static electricity so lets start the project____*

                 Here's a preview how it look

 

      BY using following parts :-

       ~ 3 NPN transistors ( bc547 )
       ~ 3 Resistors ( 1m , 100k , 220 ohm )
       ~ one led ( red )
       ~ a piece of copper plate as a detector
       ~ a voltage source ( 6 volt to 5 volt )
       ~ use a small piece of thermacoal sheet on the copper plate to make it
           more efficient because it will help to catch the charge quickly~~~!!!!

    

   HERE's the complete circuit for the detector

 

THIS SIMPLE CIRCUIT TO DETECT STATIC ELECTRICITY IN  THE SURROUNDING ANYWHERE ANY TIME AND ALSO USED AS A WIRELESS MAIN CABLE TESTER BECAUSE OF THE PRESENCE OF MAGNETIC FIELD CREATED BY CURRENT FLOWING IN THE MAINS CABLE


       This circuit is so sensitive it will detect "mains hum." 
       Simply move it across any wall and it will detect where the
       mains cable is located. It has a gain of about 200 x 200 x 200 = 8,000,000
       and will also detect static electricity and the presence
       of your hand without any direct contact.
       You will be amazed what it detects! 
       There is static electricity EVERYWHERE!
       The input of this circuit is classified as very high impedance.


PLACES where you can found the static electricity!!!

~ near to any mains cable or any plug top
~ if you have a cat so rub her fur it will create a static charge
~ if you have a crt tv take this detector to near the screen also there is static charge is present

friend's i hope you like this project and if you have any query related to this project so feel free to ask question , you can comment or if you shy to comment   so mail me  >>*_*<<


************_______THANK U GUY'S FOR WATCHING MY Blog_______***********