Sound activated switch circuit ON/OFF

Here is a simple sound activated circuit assemble this circuit the transistor is directly driven from the speaker output , a capacitor connected with a relay in parallel to avoid some small gape ( intervals)  connect it with your mobile phone ring output ,save a continuous tone (beep) in your mobile , set this tone for specific contacts (family members)now assemble it with your house main gate lock ,keep your mobile in silence profile just set continuous beep for specific family members by calling the mobile output will be appear from mobile ring output it will trigger the relay this relay will drive another relay it will  trigger the lock on, Only known contacts will access the main gate other unknown will not be entertained where there will be no output if unknown will call.lock will be remain open while ringing continues.

homemade pcb making

For any electronic circuit assembling it required a PCB board ,it may be bread board, dotted board or special PCB board which you have to design and then printed
You need to have a laser printer with a maximum DPI ,for clear print , for paper search for shiny surface like used in monthly magazine would be a great choice, cloth iron used for 3 to 5 minutes after printing 2 basic etching procedures are followed ,for one a ferric chloride is used , the other is a solution of HCL + hydrogen peroxide ( HCl + H2O2),
You must learn any PCB design software like Cad Soft , where you express you idea better .

Motor Control Circuit

A very Classical motor driver circuit found in many appliances, this circuit is made around two 5 pin relays, here DC power to the motor in either direction will be possible by the both relays by pressing the buttons, if button S2 pressed –Ve current will flow through relay K2 coil , to the +Ve terminal.by activating the relay K2 , the relay (C) point will be connected to the ( NO) , +Ve  will be flow towards (motor SV1-2) , the –Ve for this motor SV1-1 will be routed through K1 ( C & NC ), it will rotate in one direction , if button S1 pressed –Ve will flow through S1 ( 1 & 2) will energized relay K1 , -Ve will flow through K2 ( C & NC ) & +Ve will flow through K1 ( C & NO ) pins 

ON/OFF Switch GSM based (DTMF)

Below is a simple on/off switch using GSM mobile network .It will work on miss call option , for which you don't have to pay , one miss call for ON and other for OFF .due to the latching output from the decoder 8870 & 4028 IC , it is recommended to record two DTMF tone in mobile & set it as a ring tone for a specific user ,It means that if we call the said mobile , lets i have set 2 DTMF tone 9 & 6 , output from IC 4028 pin # 5 which having # 9 DTMF tone is connected to opto-coupler PC817 then it is connected to IC 4013 ON/OFF switch ,Once you call the mobile it will once activate (on) the pin # 9 while DTMF tone # 9 was set first , than after it tone # 6 will be observed at 8870 , so it will activate # 6 , pin # will be off ,again by calling the  the mobile circuit will be ready for the next action either off or on.For confirmation a simple switch will be added to make call busy or continuous ringing which will confirm that the desire action ON or OFF successfully done.

                           

                                   

CAR TRACKER (GSM + GPS)

  In this project a phone set required having built-in GPS module where you can get location coordinates and GSM location through sms from your vehicle,There will be call originated from car while someone try to open car door.  You can get alert  from car while someone try to open car door   For call originating from car will required speed dial option in mobile phone set.  First enable speed dial option, save your number with specific digit ,  solder the desire button,   now   both wires from the will be interface with car doors switch, It means that if someone open the door switch will be operated resulting to dial the specific  speed dial  number.  Basic concept in circuit is that despite of different cellular mobile phone number in the tracking car should pass a combination (sequence) lock key, for this a simple 4081 AND gate IC were used where 4 keys required in a desire sequence, these 4 inputs were taken from 4028 (4 bit binary to decimal converter) IC to 4081, which is directly connected to 8870 DTMF IC outputs, in the last a simple touch on/off circuit were used from IC 4013.Interface between ICs 4028 & 4081 were done with the opt coupler PC817, Once sequence completed in IC4081, reset will required it is then done while using relay 2 along PC817.
Features:-

                      1):-   Get location all over Pakistan with Google Map
                      2):-    Alert while someone nearby Car.
                      3):-   Full control using DTMF remote control.
                      4):-   Only specific users can access control.

                      5):-   Engine Kill release option 

FM Transmitter 6 Watts

Below is the versatile FM Transmitter build around car MP3 player ,which can deliver up to 6 Watts.In this circuit RF signal is taken from a MP3 player built-in low power transmitter, it is than boosted by the two more RF stages ,For making any RF transmitter circuit at least two meters are very necessary , one is frequency counter & the other is RF field strength meter.In the first stage of transmitter one of the best driver transistor 2SC2053 were used .you can use the other transistor up to 500MW power for this stage.In the second stage another RF transistor 2SC1971 were used.also you can use any equivalent transistor. Note : L3 will be 4 turns , L6 will be 12 turns, Heat Sink required for 2SC1971 (C2053 can be used ).
RF field strength meter also available below, up to 3 different circuit i have tested photo added.

https://obaidkakar.blogspot.com/2019/10/fm-transmitter-25-watts-88-108-mhz.html

arduino-gsm-jammer-900-mhz

                                   

https://obaidkakar.blogspot.com/2018/08/arduino-fm-radio.html AliExpress.com Product - 5pcs 2SC1971 C1971 TO-220 35V 2A AliExpress.com Product - 10pcs/lot 2SC2053 C2053 TO-92 NPN transistor, VHF RF amplification


RFC COIL: 0.68 uH



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