Circuit Diagram Knowledge: voice

Showing posts with label voice. Show all posts

Sunday, October 5, 2014

Mini Voice Operated Relay circuit diagram

This is the circuit diagram of a voice operated relay. It similar with sound activation switch circuit which will turn on and turn off (connect and disconnect) the switch depending on the sound input. The output switch of this circuit is act by a relay.

Mini

Component Parts list:

R1, R7 1K R2, R4, R8 10K R3 2K2 R5 1M R6 200K R9 39K D1, D4 1N4004 D2, D3 1N4148 C2, C5 2.2uF/16V mini ecap

C1 10uF/16V mini ecap C4 100pF C3 100nF Q1 BC548 IC1 LM358 (of Hitachi HA17358) 8 pin IC socket Relay AX-SH-112L LED 3mm Electret microphone

This mini-VOX – voice operated relay – is based on a circuit published in Silicon Chip, 9/1994, p31.

The off delay time may be adjusted by varying R3 and R4. Reducing R3 will result in a longer release time.

You could change the release time constant (C2 & R5) to say 30 seconds and use the VOX as a light switch with this delay time before turning off. Increase C2 to say 10uF and R3 to 3M3.

To make the easy adjustment, you may use potensiometer or trimpot to varying the value of resistor. You will need additional place on the PCB but it will easier for you to make some adjustment

The kit of this circuit available at kitsrus.com anf electronickits.com, you may buy the circuit there.
HERE the manual instruction of this Mini Voice Operated Relay circuit

Here continue read..

Sunday, December 22, 2013

Voice Scrambler

With this circuit you can modify how your voice sounds by changing the pitch of your voice. This circuit can be connected to a phone and with a duplicate circuit on the end of the phone line, you can have a scrambled voice communication. The way the circuit works is as follows: If we cut the circuit in half at the T2 transformer and include the LM324 on the left side, you will see that the LM324 portion of the circuit is a tone oscillator which shifts the frequency of all input signals to a new higher frequency.

When the voice and the tone oscillator mix frequencies the voice is not recognized. The voice signal is then inputted to the second stage which again shifts the voice signal again. I recommend that the first stage be tuned to a frequency that is 100hz lower then the second stage.

Here continue read..