Microphone keeping beat

[Xyver]

Can you make a circuit where a microphone listens to a beat (the bass in a song) and then blinks a light in response to that?

The scenario would be in a nightclub/rave/anywhere with loud music, would it work?  Or would there be too much background noise, and the microphone would be confused and not pick up the beat.

The project I'm thinking of is techno gloves that flash lights to the beat of the music.  Plan B is put a potentiometer on them so you can adjust the speed of the blinking to the beat of the music.

[Soeren]

Hi,

Can you make a circuit where a microphone listens to a beat (the bass in a song) and then blinks a light in response to that?

Of course, but I fail to see the connection with robotics ??

Back in the seventies, we called such circuitry "Light Organs" and the better of them was made with filtering into 3 or 4 frequency bands.
A 4 pole low pass filter should suffice '(perhaps even 2 poles might do) or an elliptic filter (made with L's and C's) using an f_3dB of say 300Hz to 600Hz - you could make FFT analysis of some typical rave music to find the optimum frequency to use.
Clapping and loud/sharp noises at higher frequencies would set it off as well - analog filters cannot be made as brick wall steep as digital filters, but a DSP would be serious overkill for this.

The scenario would be in a nightclub/rave/anywhere with loud music, would it work?  Or would there be too much background noise, and the microphone would be confused and not pick up the beat.

I have never been to a rave, but I have an impression, that it's more or less people on E, Pogo'ing to electro-music, instead people on W(hiskey) to Rock'N'Roll  - so I assume the signal/noise ratio won't be all that different - perhaps better (except for your ears), given the last few decades of amp and speaker development though.

The project I'm thinking of is techno gloves that flash lights to the beat of the music. 

You could up that with a string of LEDs each finger and let the light flash out along the fingers (with a slower retract) - something like an LM3915.
This could even be made in a controller, triggered by the output from the preamp/filter - and if you wanna go nuts, use RGB LEDs - colors could fade and blend - expanding and retracting, or color could be determined by the rhythm (the b.p.s.), the overall frequency components of the music, or whatever you can imagine.

Plan B is put a potentiometer on them so you can adjust the speed of the blinking to the beat of the music.

Bad idea IMO, but could be realized with a controller as well - hold a button for eg. 2 seconds (to enter "learn mode") and then tap it twice to the beat. Then it knows the interval (until the next piece of music - but... I'm not sure the girls will find it all that attracting, that you have to reprogram your gloves at each new piece of music - and let's face it... The girls are the reason that we go to such places )

[Xyver]

Oh Soeren... You make me laugh xD  And you always answer my posts with good answers   And this may not be directly related to robotics, but this is my favorite forum for getting technical questions answered (even though I've been neglecting robotics and electronics for awhile... Curse you modelling!)

I don't go to places like that either (clubs, raves, bars, concerts...)  but my friends have commissioned me to make gloves for them.  I've already got some nuts ideas, and I'm pretty sure I have everything worked out, except the microphone.  You're answer has told me that you know how to go about this, but I don't understand everything you've written.

I'll ask questions in step by step form. 

What type of microphone would be suitable for this, and where could I buy one for cheap(ish) (hopefully ~10-20$?)

[Soeren]

Hi,

I don't go to places like that either (clubs, raves, bars, concerts...)

How do you keep your brass knuckles shiny then?

I'll ask questions in step by step form. 

So old farths can keep up you mean? 

What type of microphone would be suitable for this, and where could I buy one for cheap(ish) (hopefully ~10-20$?)

Cheap electret capsules are aces (some are even used to make reference and measuring mikes).
Less than $1 on Mouser, but any electronics shop will carry them - if you need enough for 5 pairs of gloves (i.e. 10 capsules), you may save a bit on ebay or such and getting identical units will help make them behave the same.

They come in different impedances, sizes and qualities (you only need the cheapest, they're all very sensitive.
You may have one or more already - they're in almost any PC microphones.
They need a bias voltage (through a resistor) and some have 3 terminals, some only 2 (the latter needs a cap to isolate DC from the output.

Before ordering a truckload of this and that, make a prototype and assure its functionality.