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This is a newer version of previous device. This one can have up to 6 relays and 6 sensor-state inputs. The task was to build a device that connects to the phone line and has a relay as an output switch. It should also sense if the connected  «consumer» is turned-on or off and report to the administrator at the other end of the phone line. The administrator would then call-in the device, log in with the password, and check the state of  «consumer», turn it on or off, change password or some other settings. Download : Schematic, Program files And Documentation Schematic: Full Schematic Telephone operated remote control

Here is the circuit of clap-operated remote control fans is used to control not only switching properties but also control speed of fan. The main advantage of clap operated remote control for fan is, it can control up to ten-step speeds of fan where normally a fan has three to five step speeds.   Circuit description clap operated remote control for fan This entire circuit clap operated remote control for fan is divided into four major section i.e. sound-operated trigger pulse generator, clock pulse generator, clock pulse counter and load operator. Sound-operated trigger pulse : – The heart of this section is transistor T 1 BC148, configured as class-C amplifier mode. The MIC 1 is used to change voice signal into its corresponding electrical signal and is given to base of transistor T 1 in order to amplify and increase its intensity. Clock pulse generator :- This section is build around timer IC NE555 and configured as monostable multivibrator. The trigger pulse generated by tran...

Sometimes ringing the bell manually becomes difficult, especially when you are holding something in your hands. The sound-operated music bell takes care of the problem .In this circuit, the use of an external relay has been eliminated. The circuit comprises a trigger stage (around BC548B), a timer stage (NE555) and a melody stage (around UM66 and SL100). Transistor BC548B is biased inn class C operation. Every second sound cause triggering at pin 2 of 555 timer IC.                                                                                When VR1 is at maximum, the hold-on time of NE555 is around 3...

This is the Simple Battery operated emergency light Circuit Diagram. This simple circuit providers battery operated emergency lighting instantaneously upon failure of the regular ac service. When line power is restored, the emergency light turns off and the battery recharges automatically. Battery operated emergency light Circuit Diagram     The circuit is ideal for use in elevator cars, corridors and similar places where loss of light due to power failure would be undesirable. Completely static in operation, the circuit requires no maintenance. With ac power on, capacitor CI charges through rectifier CRI and resistor Rl to develop a negative voltage at the gate of the C106Y SCR . By this means, the SCR is prevented from being triggered, and the emergency light stays off. At the same time, the battery is kept fully charged by rectifier CR2 and resistor R2. Should the ac power fail, CI discharges and the SCR is triggered on by battery power through resistor R3. The SCR t...

This solid state DC switch can be assembled using just three transistors and some passive components. It can be used to switch on one gadget while switching off the second gadget with momentary operation of switch. To reverse the operation, you just have to momentarily depress another switch.  The circuit operates over 6V-15V DC supply voltage. It uses positive feedback from transistor T2 to transistor T1 to keep this transistor pair in latched state (on/ off), while the state of the third transistor stage is the complement of transistor T2’s conduction state.  Initially when switch S3 is closed, both transistors T1 and T2 are off, as no forward bias is available to these, while the base of transistor T3 is effectively grounded via resistors R8 and R6 (shunted by the load of the first gadget). As a result, transistor T3 is forward biased and gadget 2 gets the supply. This is indicated by glowing of LED2.  Circuit diagram : Solid-State Switch For Dc-Operated Gadgets Circu...

This is a Simple Sixteen Way Clap-Operated Switch Circuit Diagram . Control your home appliances without getting out of your bed. You just have to clap in the vicinity of the microphone used in this circuit, which you can keep by the bedside. You can switch on/off up to four different electrical equipment (TV, fan, light, etc) in 16 different ways.This circuit is built around timer IC 555 (IC1), CMOS IC 74LS93 (IC2) and five BC547 npn transistors (T1, T2, T3, T4 and T5). Transistor T1 is used as the preamplifier and the rest are used for driving the relays. Sixteen Way Clap-Operated Switch Circuit Diagram   A small condenser microphone is connected at the base of transistor T1, which is biased from resistor R1 (10 kilo-ohms). The clapping sound is converted into electrical energy by the microphone and amplified by transistor T1. The transistor output is fed to the monostable circuit wired around IC 555. Output pin 3 of the timer is connected to the clock input of divide-by-16 ...