[Moved] Sound activated strobe light

[bogdanux]

Hello everyone,
I'm an amateur of electronics, and i beg also pardon for my english, but i want some help on a strobe i bought a year ago. My strobe is a little one, for a small party at home or so, and the problem is that it only has a speed knob on it. That means that i can set how fast it blinks, which is good enough, but i noticed that generally, people don't like seeing a strobe light on all the time. So, inspired by another device (also some kind of disco light) which lights some LEDs acording to the bass, i decided that i would like to modify my little strobe, by adding a small microphone, then a low pass filter (Simple RC first order low pass with a cut frequency around 2khz) then the rest of the circuit. I'm posting the pictures of the actual strobe.
Is it possible to do this kind of modification on this device, knowing that i don't want to modify it's actual PCB very much, but still obtaining the "sound driven" effect?

P.S.: i live in an EU country, so the voltage here at the outlet is 220V, at 50hz (i think), and the strobe plugs directly into that.

 

[barry]

It looks like what you've got there is a neon-bulb relaxation oscillator driving your xenon flash tube. The way this probably works is that when the neon bulb fires, it generates a trigger that fires the flash tube. I don't think this is readily adaptable to your idea, and without the schematic it's nearly impossible to tell you how to modify this.

 

[bogdanux]

So it's kind of a dead end?

 

[FvM]

The trigger transformer is controlled by a thyristor, it could be triggered by a different circuit. I see however some problems:

- you need to add a low voltage power supply for the filter and trigger circuit
- apparently you don't have yet a clue how to make the trigger circuit (besides using a low-pass filter)
- you don't know how to extract the schematic of the very simple free running stroboscope circuit, how do you think to modify it?
- everything you add, e.g microphone, amplifier, filter will be directly connected to the mains and carries a hazardous contact voltage. Using an optotriac or other optocoupler can be a safe solution.

 

[bogdanux]

Thank you very much for your time, effort and answers.
As i said in the first post, i'm a newbie so I apologize for not knowing much about it.
At first I thought that I could connect some components to the mains, then hook them up to the circuit board and I know this is risky as the device operates at a pretty high voltage.
Also I didn't know that I have to give the schematic.
I apologize for all the nonesens.

 

[FvM]

I don't think it's nonsense. It can work but some electronic design skills are necessary. The hazardous voltage point is probably the most problematic one.