similar to clap on clap off need help

[Traceyhardy]

Okay what i am trying to do is basically the same thing as a clap on clap off relay. i have a schematic diagram but im not actually sure what im doing wrong. I know Q1 acts as an audio amplifier. IC1 timer, wired as a monostable, provides a clean output signal and a reasonable time delay in order to allow proper switching of the following bistable circuit. A discrete-components circuit formed by Q2, Q3 and related parts was used for this purpose, in order to drive the Relay directly and to allow 3V supply operation. But, i want to have a led light as my load as its indicator. I couldn't figure out how to place my multisim schematic so i had to post this one.

 

[jarph]

um...take out relay, put in LED? This doesn't work?

 

[Traceyhardy]

Need help asap

Maybe i should have explained what im trying to do better. R1,R6___________12K 1/4W Resistors
R2_______________1M 1/4W Resistor
R3,R9____________6K8 1/4W Resistors
R4_____________220K 1/4W Resistor
R5_______________2M2 1/4W Resistor
R7,R10_________100K 1/4W Resistors
R8______________22K 1/4W Resistor

C1,C3__________220nF 63V Polyester Capacitors
C2,C4,C5________22nF 63V Polyester Capacitors
C6______________47µF 25V Electrolytic Capacitor

D1,D2_________1N4148 75V 150mA Diodes

IC1_____________7555 or TS555CN CMos Timer IC

Q1_____________BC550C 45V 100mA Low noise High gain NPN Transistor
Q2,Q3__________BC328 30V 800mA PNP Transistors

MIC1___________Miniature electret microphone

SW1_____________SPST Switch

RL1_______________5V DIL Reed-Relay SPDT (See Notes)

B1________________3V Battery (2 x 1.5V AA, AAA Cells in series etc.)

I want to control my tv (led) with a voice frequency. If it reaches a certain frequency i want the tv to turn on and so forth. Why wouldn't I have a relay. basically your saying i don't need a relay? I don't really understand the schematics how did they determine the component values. Can you help me in this matter?

 

[Analog]

Maybe i should have explained what im trying to do better. R1,R6___________12K 1/4W Resistors
R2_______________1M 1/4W Resistor
R3,R9____________6K8 1/4W Resistors
R4_____________220K 1/4W Resistor
R5_______________2M2 1/4W Resistor
R7,R10_________100K 1/4W Resistors
R8______________22K 1/4W Resistor

C1,C3__________220nF 63V Polyester Capacitors
C2,C4,C5________22nF 63V Polyester Capacitors
C6______________47µF 25V Electrolytic Capacitor

D1,D2_________1N4148 75V 150mA Diodes

IC1_____________7555 or TS555CN CMos Timer IC

Q1_____________BC550C 45V 100mA Low noise High gain NPN Transistor
Q2,Q3__________BC328 30V 800mA PNP Transistors

MIC1___________Miniature electret microphone

SW1_____________SPST Switch

RL1_______________5V DIL Reed-Relay SPDT (See Notes)

B1________________3V Battery (2 x 1.5V AA, AAA Cells in series etc.)

I want to control my tv (led) with a voice frequency. If it reaches a certain frequency i want the tv to turn on and so forth. Why wouldn't I have a relay. basically your saying i don't need a relay? I don't really understand the schematics how did they determine the component values. Can you help me in this matter?

what do you mean voice frequency? A specific tone? So when the TV's on and it produces that tone or frequency it will shut itself off? Do you see the problem with this?

 

[audioguru]

The microphone and its preamp will respond to all audio frequencies. There is nothing in the circuit to tune it to one frequency. That one frequency will occur frequently with music and speech anyway.

 

[Traceyhardy]

I understand what you are saying what modifications do i need to make

 

[audioguru]

You could use a bandpass filter to tune just one frequency. Then the circuit will be activated whenever that frequency occurs.

"That one frequency will occur frequently with music and speech anyway."

Telephones use Double-Tone-Multi-Frequency (touch-tones) for dialing. Because there are two tones with their frequencies unrelated, they are not activated very often with music and speech.

 

[Traceyhardy]

Thank you very much. Your feedback was very helpful. Last, questions. How do i go about determing the values for the components?

 

[audioguru]

Thank you very much. Your feedback was very helpful. Last, questions. How do i go about determing the values for the components?

You can look up Bandpass Filter in Google. Articles will have calculations for the circuit's frequency determining parts.

 

[rejithcv]

reply

First of all you didn't specify the actual purpose. If u want to switch of the relay at a particular frequency the easiest way is using a pll circuit build around the commonly available ic NE567. You may also need to replace the timer ic with a flip- flop if u want to make the tv on for prolonged time (not timer). It seems quite hard to switch on a tv set using relays of abt 3v. You can possibly replace with a triac (in this case u shuld be aware of shock)


-rejith

 

[Traceyhardy]

I am so confused... I just need to know how the circuit in the attached document works and how u determine the component values. I was told that a simple bandpass filter wouldn't be feasable for such a simple design. I am going to alter this design for my circuit to turn on a led (tv) but i first would like to understand this one.

 

[audioguru]

I just need to know how the circuit in the attached document works and how u determine the component values.

You need to understand how a transistor and a 7555 IC work. Then you can design the parts values.

I was told that a simple bandpass filter wouldn't be feasable for such a simple design.

Speech and music make a single frequency too often.

I am going to alter this design for my circuit to turn on a led (tv) but i first would like to understand this one.

The relay is much too small to turn on a TV. Replace it with an LED in series with a current-limiting resistor. With only a 3V supply then only a red LED will work. Blue and white LEDs need a higher voltage.

 

[Traceyhardy]

I did that in my circuit on multisim i just couldn't post that on the attachment

 

[audioguru]

With the schematic on your screen, just press the PRT SCRN key then paste it into Microsoft Paint program, save it as a GIF or PNG file type and attach it to a reply.

 

[Traceyhardy]

I tried that but it wont save as a valid file

 

[audioguru]

Then your Multisim program is useless for getting help from this forum.
Sketch the schematic in Microsoft Paint like I do. I copy and paste parts of other schematics and datasheets to make a clear schematic.

 

[Traceyhardy]

i think this works

 

[audioguru]

Your schematic is posted as a fuzzy JPG file type that is used for photographs. It would be much clearer if it was a GIF or a PNG file type. I don't know why it is so small.

I didn't compare it with the original circuit but I found some problems and marked them:

 

[Traceyhardy]

I went back and fixed the led diode and changed the coil resistance to 100k ohm but what do you mean most of my circuit doesn't have a power supply. What should my output voltage me from my 555 timer?

 

[audioguru]

I went back and fixed the led diode and changed the coil resistance to 100k ohm

You will never find a relay with a coil as high as 100k. Now its resistance is much too high and the flip-flop won't work.

what do you mean most of my circuit doesn't have a power supply.

The 555 IC and the transistors don't have a power supply. Only the LED is connected to the battery.

What should my output voltage me from my 555 timer?

The original circuit uses a Cmos 7555, not an ordinary 555. They are different.
Their datasheets show their output voltage that changes with the amount of output current. This circuit has a low output current so a Cmos 555 has an output voltage that goes up to the supply voltage and an ordinary 555 has an output voltage that goes up to about 1.2V less than the supply voltage and might not go high enough for the flip-flop.