Audio switch or amplifier, controlled by voltage, single supply, how to?

Hello,

not using an Arduino... Basically I'd like to make an audio bip, when a light is flashed. Audio quality can be poor, the reaction time needs to be fast (1ms max). Should be battery operated (5V single supply for instance). Mic or line level out will feed a regular audio interface.

I though I could control the output of a simple audio oscillator with the output of a light detector.

I have ideas about how to do the audio oscillator circuit (NE555), the light to electrical tension circuit (phototransistor with transimpedance amplifier), but none viable for the circuit that would control the passing or not of the audio signal from the oscillator.

So what would you do if you had an audio signal that would be either:

-voltage controlled (scaled according to a voltage command)

-voltage switched (switched on/off according to a voltage command (being higher than a threshold for instance)).

Both case would fit my needs, the simplest/cheapest would be the best.

I would appreciate any hints... thanks.

Best regards.

I think no-one's answered because they can't figure out what you really want - can you reword and ask again?

Ok, thanks for your answer, I'll try...

The goal is making a simple battery powered device that would be able to detect a flash (a sudden change of luminosity), and output an audio bip (thru a mic or line level signal), so that that bip could be recorded, or actually be connected to a loudspeaker.

The idea I have is the following: an audio oscillator works continuously, but it output is shut by an electronic switch. The switch is controlled by a light detector: if there is enough light, the switch let the sound pass.

I have ideas for the oscillator parts, for the light detector, but I'm stuck with the switch.

I guess a comparator can give a logic 0 or 1 if the light detector goes above/below a reference level, but what kind of IC can block or let pass an audio signal on such a logic control?

Audio don't need to be very good, only response time is important (i.e. the bip should begin less than 1ms after the flash).

Hope it's clear now...

Best regards.

You can connect the LDR / photodiode sensor to pin, that have hardware interruption capability, than generate a bip by Tone command. http://arduino.cc/en/Reference/AttachInterrupt http://arduino.cc/en/Reference/Tone

Thanks for your answer,

I forgot to rephrase also the part "without using an arduino".

I'm sure a simplest way exist, as an Arduino is too capable for this...

And I would learn something about electronic.

I have ideas about how to do the audio oscillator circuit (NE555), the light to electrical tension circuit (phototransistor with transimpedance amplifier), but none viable for the circuit that would control the passing or not of the audio signal from the oscillator.

Instead of control the passing, would it be easier to control oscillator itself, especially 555, which has special pin for this? It's not clear how long bip should be, probably you could design circuit with two 555, one generate sound frequency when second "monostable" - triggered by light sensor 'd allow first one to operate for specific period of time.

Thanks for your answer, that's indeed a good lead.

I've searched, and found the 4066 a cmos (quad analog switch) that may be the kind of things I'm looking for.

Does someone knows other IC with the same kind of function than a 4066?