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using sound to deliver a laser pulse.

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I would like to be able to trigger a laser pulse from a microphone input to a PC.

Is it possible to use the audio output or some other output port to do this?
Thanks. Ian
 

TheDukeAnumber1

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You need to be more specific, especially when asking for help on your first post.

I would like to be able to trigger a laser pulse from a microphone input to a PC.

Is it possible to use the audio output or some other output port to do this?
I can't tell what your trying to do here, mic to laser then laser to audio output on pc?

Here's the answer to your question though.
 
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Sorry if I wasn't very clear.
What I would like to achieve is this -
A brief sound (clap of hand etc) into microphone which is plugged into PC, triggering a pulse of power from a computer output port to the laser.
The PC audio output is AC and probably not powerful enough to fire the laser.
 

TheDukeAnumber1

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I think the audio output would be DC not AC. Do you know the output capabilities of the jack you want to use?
 
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Probably 2 or 3 volts, but it won't drive a laser directly - ie when I connect a sound system, the audio output is not enough to light the laser.
 

Sigurthr

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It can certainly be done, but your application is vague and you haven't included important details.

Before I put effort into helping you (mostly by designing the analogue circuit to do the job), can you elaborate on the application? Why does a computer need to be involved at all, for example?
 

Ian Watson

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Thank you, but no, I need an un-latched switch as I only want the laser to be switched on for a fraction of a second

The idea is to mount a laser to the barrel of a blank-firing pistol and use the noise of the blank to fire the laser at a suitable light-sensitive target as a safer alternative to a pellet or bb.
Such pistols are available, but are very expensive and not readily available.
I should state that this is not a commercial enterprise, but merely a home project.

A non-latching switch might do the trick if I could find something suitable, but I thought using a PC might give better control over sound level, and duration of noise.
I want the laser to trigger once at the beginning of the noise and only remain on for perhaps 0.1 second.

Ian
 

zyxwv99

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It seems that the primary focus of your problem is the switch and how to control it. For that you might need to know what kind of electricity that switch is controlling. That would probably be electricity coming from whatever sort of batteries you are using. Knowing the battery type and how many there are should tell you the voltage and current that the switch is supposed to control. Where the electricity goes after that is beside the point. That's why it's not really a laser question.

There are two sorts of people who might know the answer to your question. First, engineers who work with remote-control systems such as automatic lawn sprinkler systems, or oil refineries which have hundreds of miles of pipes with remote-control valves.

The other sort of people are hobbyists and owners of hobby shops that sell things like parts for do-it-yourself remote-control model cars, airplanes, etc. You can probably find them online somewhere, on discussion boards devoted to those kinds of hobbies.
 

Ian Watson

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It seems that the primary focus of your problem is the switch and how to control it. For that you might need to know what kind of electricity that switch is controlling. That would probably be electricity coming from whatever sort of batteries you are using. Knowing the battery type and how many there are should tell you the voltage and current that the switch is supposed to control. Where the electricity goes after that is beside the point. That's why it's not really a laser question.

There are two sorts of people who might know the answer to your question. First, engineers who work with remote-control systems such as automatic lawn sprinkler systems, or oil refineries which have hundreds of miles of pipes with remote-control valves.

The other sort of people are hobbyists and owners of hobby shops that sell things like parts for do-it-yourself remote-control model cars, airplanes, etc. You can probably find them online somewhere, on discussion boards devoted to those kinds of hobbies.
Thank you, yes, the switching is the crucial element - this may not be the right forum for that.best forum
 

Sigurthr

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Going the audio triggered route adds a LOT of complexity to the build. You basically need a small signal audio amplifier, and you need to bias it for enough gain yet prevent oscillation, and amplifiers LOVE to oscillate. For the actual switching it is quite simple; a retriggerable one-shot 555 timer, a Nch Fet, and a pull-down resistor. If you can figure out how to attach a reed switch so that when you pull the trigger of the gun it closes the reed switch you eliminate a ton of complexity. At that point simply use the reed switch for the one-shot's trigger switch, and configure the one-shot to your choice of timing. Laser module goes between Vcc and FET's Drain, 1-10k resistor between Gate and Source, Source goes to ground/negative, Gate goes to output of the One-Shot. Voila'.
 
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What about an independent lab laser powered by it's own PSU and a sound activated switch? Won't need the computer for that since any sound will power on the laser.

I got one of these and the sound activation works amazingly well.
 




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