Remote Turn-On

Hi, Does anyone have a schematic, kit, or a complete product to sense a line level audio signal and turn a remote power amplifier on? I have done all the searches I can think of and have not found anything. These things can't be that rare!! Thanks...Mike DeAngelis

line

the

Maybe you could use a VOX, a voice activated switch often used in CB and ham radio.

-- DF

Put VS-1 in the search box.

It's a vox kit for $9.95. It can drive a 100 mA load, such as a relay, which can turn the amplifier on/off.

Ed

You're kidding right ?

Graham

I doubt many ppl need to do it.

Why not design your own ? It isn't that difficult.

Graham

No. What it is about a 100 mA load that engenders your question?

Ed

teach me how my name is sam email snipped-for-privacy@yahoo.com

Naaah! Your name is "Pest" ;-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

line

the

be

Yeah, like they said, a VOX. "Voice-operated transmission".

It seems to google up pretty good.

Have Fun! Rich

--- OK. (view in Courier)

V+

Do you need a circuit description?

-- John Fields Professional Circuit Designer

C(harge)R(apidly)1 - clever! I would not have thought of it.

Ed

some

Mike DeAngelis wrote:

The audio line activated switch is not VOX as some have claimed- VOX is largely a radio term and describes detecting a few tens of mV or less of microphone output. Your circuit is working off of 100mV,RMS minimum, and up to 2V,RMS, into 10K loading. All you need to do is gain that up, rectify, smooth, and drive a relay. Actually, you don't need to do any of that using a single transistor and a CMOS 555. The circuit below uses a 2N3904 to gain up the line input to a 5Vpp swing at the 555 TRIG input. As long as the 555 receives triggers before the 15u can discharge, which takes about 2 mins, it will remain on keeping the relay activated. No adjustment should be necessary. View in a fixed-width font such as Courier.

. . . . NEUT ------------->

. GND -+----------->

. | . .-----------' . | . (-)---------+ HOT -----o---v . 5V | o--->

. (+)---------|---------. . |100u + | | . +--||-----+ . \\ | | | . \\|--+--||-----+ . \\| 0.1U | | . | -------- . .-----+----+------+---------+---|/ / / / |-. . AUDIO | | | | | -------- | . LINE 0.022u | | +| | +------|--+-||--. | | === [120K] | 1N4001 | . | | [100K] [10M] 15U | | | . | | | | | | TLC555------. | . | [10K] | | | | | VCC/RST | 2N4401 | . | | | | | | | | |/ . | +-[4.7M]-+-| . | | 22p | | | | | | . | +---||---+-----------------|---|TRIG DIS|--. | . | | | | | | | | | . | | | | | | | | | . | | |/ | +---|CONT | | | . | '------|2N3904 | | | | | | . | |> | | | GND | | | . | | | | '-----------' | | . [1M] | | | | | | . | | | [100K] | | | . | | | | | | | . | | | | | | | . | | | | | | | . '--------------+-----------------+-----------+------|-----' . | | | . --- | | . /// '-------------------------' .

. . . . NEUT ------------->

. GND -+----------->

. | . .-----------' . | . (-)---------+ HOT -----o---v . 5V | o--->

. (+)---------|---------. . |100u + | | . +--||-----+ . \\ | | | . \\|--+--||-----+ . \\| 0.1U | | . | -------- . .-----+----+------+---------+---|/ / / / |-. . AUDIO | | | | | -------- | . LINE 0.022u | | +| | +------|--+-||--. | | === [120K] | 1N4001 | . | | [100K] [10M] 15U | | | . | | | | | | TLC555------. | . | [10K] | | | | | VCC/RST | 2N4401 | . | | | | | | | | |/ . | +-[4.7M]-+-| . | | 22p | | | | | | . | +---||---+-----------------|---|TRIG DIS|--. | . | | | | | | | | | . | | | | | | | | | . | | |/ | +---|CONT | | | . | +------|2N3904 | | | | | | . | | |> | | | GND | | | . | | | | | '-----------' | | . [1M] | 1N4148 | | | | | | . | '--|