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The objective of a remote control is to have the ability to operate a device from a certain distance. Nevertheless, remote controls usually are in places where we need to move around to find. This makes the remote totally useless as you may have used that time and energy to operate the device personally. If we take into account the limited reach that remote have, along with the fact that they are battery operated, we have an obsolete technology. All this can be fixed by developing a new remote control system. A lot of designs have been completed on systems that operate by clapping. But they have some disadvantages. Such as the fact that they work over only one sound or command. Another fact is that daily activities must be interrupted to give a command. A whistling command system has been developed to control domestic devices. It works by detecting the sound peaks that are uniquely produced by whistles. Sound from each whistle is processed to give the order to the device....

( Simple add-on module Switchable "Control-flat" option ) In order to obtain a good audio reproduction at different listening levels, a different tone-controls setting should be necessary to suit the well known behaviour of the human ear. In fact, the human ear sensitivity varies in a non-linear manner through the entire audible frequency band, as shown by Fletcher-Munson curves. A simple approach to this problem can be done inserting a circuit in the preamplifier stage, capable of varying automatically the frequency response of the entire audio chain in respect to the position of the control knob, in order to keep ideal listening conditions under different listening levels. Fortunately, the human ear is not too critical, so a rather simple circuit can provide a satisfactory performance through a 40dB range. Circuit diagram : Simple Automatic Loudness Control Circuit Diagram The circuit is shown with SW1 in the "Control-flat" position, i.e. without the Automa...

This simple Telephone Record Control Circuit Diagram will allow you to connect any tape recorder that has a mic and remote input to a phone line and automatically record both sides of a conversation when ever the phone is in use. You will need to take a couple of voltage readings before connecting the circuit. First determine the polarity of your phone line and connect it to the circuit as shown and then determine the polarity of the remote input and connect it to the circuit. Circuit operation is as follows. When the phone is on hook the voltage across the phone line is about 48volts dc. When the phone is off hook the voltage will drop to below 10volts dc. When the line voltage is at 48volts the FET is off which causes Q2 and Q3 to be off. When the phone is picked up the FET turns on along with Q2 and Q3 which turns your recorder on. The tape recorder must be in the record mode at all times. As you can see the power source for the circuit is the phone line.  Telephone Record Con...

We would like ti show you the circuit is similar to the above, but uses an N-channel MOSFET, as IRF511, 540, 640, etc. instead of the NPN transistor. Smaller MOSFETs can be used, but I do not know the part numbers. I tested the circuit with a IRF640, IRF511, IRFZ34 and REP50N06. The same circuit has three advantages, but requires only a few parts, always off to the relay and do not need a switch debounce. In operation, when the relay is deactivated, the 100uF capacitor charge up to 6 volts. When the button is pressed, is on the capacitor 6 volts at the gate MOSFET. The capacitor voltage (and gate voltage) of 6 ms should drop to 3 volts in about 200 to move enough time for relay contacts. At very slow relay, a larger capacity. With the ratification of the relay, the contacts 12 volts to the resistance produce valid 3.3K 6 volts at the gate, holding that the relay is self-sufficient. The capacitor is then discharged to zero since the relay contact 12 is connected not to the 15K resistor....

This doorbell control porch light using timer ic (ne555),can be used in doorbell in order to get indication of porch light with door alarm if any one rings the door bell. Doorbell Control Porch Light Circuit Diagram: The circuit of doorbell control porch light is build around timer IC NE555 (IC2) and is here used as astable multivibrator. The output at pin 3 goes high of IC1 when trigger is given to pin 2 from power supply. Here transistor T1 is used as relay driver transistor which energized relay when output from pin 3 of IC1 is high. After relay energized AC current flow via N/O terminal and switch on the porch light. Triac1 with Diac1 hear is used for switch in order to glow porch light during night and switch it off at day with the help of preset VR1 and LDR1. Note:- Here the power source of 230V AC is replaced by 110V with replacing transformer having primary 110V and secondary 12V. Rest of the circuit  of door bell controll porch light is same. PARTS LIST : Resistors (all ¼...