The frequency of this transmitter circuit must be first set to the receivers matching frequency which is calculated to be 2kHz. The circuit is based on a simple AMV concept using a few ordinary transistors and some other passive parts. The following circuit may be utilized for generating an audible frequency for the above described sound remote receiver circuit. Sound Activated Remote Transmitter Circuit The output may be directly connected with a relay if only a momentary toggling is required or only for the time the input is active.įor an ON/OFF switching the same may be configured with a FLIP-FLOP circuit. The IC immediately acknowledges the matching data and reverts the output into a low for the necessary actions. The mic converts the sound into electrical pulses corresponding to the received frequency at the relevant input pin of the IC. In the discussed sound triggered remote control circuit, a MiC is configured across pin3 of the IC.Īn external matching frequency (2kHz) in the form of an audible sound or whistle is pointed toward the mic such that the sound hits the mic starighton. This low at pin8 sustains as long as the frequency at the input pin stays active, and becomes high as soon as it's removed. Once the IC detects this, it produces a zero logic or an instant low at its output pin8.
Pin3 is the input of the IC which tracks, responds and locks on an frequency which may be reaching the 2kHz figure. Where C is in farads, R is in Ohms while F is in Hz. The formula for determining the latching frequency across pin5/6 may be calculated using the following formula: The IC will lock-on into any frequency that's fed across its input and which exactly matches the frequency fixed across its pin5 and pin6 via the relevant R/C components. We have already learned a lot regarding this wonderful frequency decoder LM567 IC.
SOUND CONTROL SWITCH GENERATOR
The figure shows the circuit of a sound detector circuit which can be effectively converted into a remote control, triggered using a sound generator handset. Therefore it's perfectly foolproof since it won't be disturbed through other unwanted sound or noise. The next project below explains a simple, accurate remote control system through sound vibration that will work on a particular sound frequency.
It can also used as a sound toggled night bed room light circuit 2) Sound Activated Switch with Customized Sound Frequency The concept can be used as a vibration activated LED lighting, for sound triggered recording systems. Relay = coil voltage as per the supply voltage, and contact rating as per the load specs.The best possible R1 value for effective response to audio or noise signal could be determined only through some practical experimentation.Īll of the related and essential electronic protection precautionary measures is required to be implemented each time a mains AC powered load is to be connected with the relay contacts. Lower values will increase the sensitivity of the MC and the circuit, and vice versa.Īn electret microphone commonly possesses just one central FET inside which strictly requires a bias voltage to function. However, you should not employ a value exceeding beyond 47μF.īiasing resistor R1 becomes the main part which decides how sensitive the MIC or the microphone can be. If felt necessary you could to increase or decrease the ‘on’ time period of the relay by modifying the uF C2.Ī larger uF contributes to an extended ‘on’ period, and the opposite way round. As soon as the sound activated switch circuit is powered ON, you might find the relay activating briefly due to the presence of capacitor C2.Īfter this, whenever you create a noise in front of the MIC, the relay is going to activate briefly depending on the value of C2 and then switch OFF.Īny AC or DC load connected with the relay contacts will subsequently switch ON and OFF in response to the relay switching.Ī couple of seconds must be allowed for the relay to be toggled off.
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