Anyone have a Metronome and a Scope?

[YouAre]

Hey Guys,

I'm currently away from school (with it's beautiful EE lab and vast array of scopes and function generators), and I'd really like to see what a metronome's headphone output looks like on an o-scope. I'm trying to see if I can use it to switch transistors, and I'd like to see what kind of offset/amplification I need to work with. So would anyone with both these items be able to do me a solid and show me the waveform and tell me the amplitude?

Thanks!

[CynicalMan]

If nobody beats me to it, I can do that tomorrow.

[YouAre]

I would be infinitely grateful! Thank you!

[egasimus]

I'm trying to see if I can use it to switch transistors

As a signal source? Maybe a sine wave oscillator, or R.G.Keen's test tone generator, would be right up your alley.

[YouAre]

As a signal source? Maybe a sine wave oscillator, or R.G.Keen's test tone generator, would be right up your alley.

I'd like to use a metronome to switch a transistor in time with what i'm playing. It'd be replacing a momentary switch

[CynicalMan]

Here you are:
http://www.youtube.com/watch?v=9vus5DJ7Kt4

This is from one of these:


The peak voltage is around 6V. You should be able to drive a flip flop pretty easily.

[egasimus]

Interesting I guess you'll be using an 4000 series analog switch IC? Do post samples when you have a result, this will be interesting to hear.

[Mac Walker]

Download audacity, find a .wav or .mpg sample of a metronome, and look at the waveform?  Just an idea....

[CynicalMan]

Download audacity, find a .wav or .mpg sample of a metronome, and look at the waveform?  Just an idea....

Most sound cards will filter out DC, which would change how a waveform like this looked.

[Mac Walker]

Don't understand your point.  Of interest would be the frequency of a typical metronome signal, the duration, and any decay (envelope).  The metronome headphone jack is also an audio output signal without any DC offset, is it not?

[defaced]

Depends on how the speaker is driven.  If it's DC coupled to the output drivers, then it can have DC offset.  If it's AC coupled, it will remove DC offset.  And for that matter, no two different metronomes will have the same output.  I highly doubt there's a standard metronome click sound that the industry uses.  Color me lazy, but I'd just build a simple 555 oscillator and use that for my trigger instead of trying to make a metronome work. 

[YouAre]

Here you are:

This is from one of these:

The peak voltage is around 6V. You should be able to drive a flip flop pretty easily.

Thank you! I tested it with a 2n3904 and an LED and it'll switch just fine, but it looks like the peak is a little bit too quick to be read by some digital circuits (like electric druid's tap LFO). I tried to feed a metronome into this setup http://electricdruid.net/images/lfo/TapCircuitV1.gif . with a metronome feeding the external sync input. I'm guessing input wants to see more of a squared pulse, than a quick peak. The amplitude is ok, but I wonder how we can make it look like more of a pulse...

Interesting I guess you'll be using an 4000 series analog switch IC? Do post samples when you have a result, this will be interesting to hear.

Never used analog switch IC's...

Download audacity, find a .wav or .mpg sample of a metronome, and look at the waveform?  Just an idea....

Need to be from a physical metronome. Trying to figure out an interface.

[slacker]

I'd just feed the signal into a comparator, which you can make using an opamp, that will turn the signal into a nice square pulse.

[CynicalMan]

Here you are:

This is from one of these:

The peak voltage is around 6V. You should be able to drive a flip flop pretty easily.

Thank you! I tested it with a 2n3904 and an LED and it'll switch just fine, but it looks like the peak is a little bit too quick to be read by some digital circuits (like electric druid's tap LFO). I tried to feed a metronome into this setup http://electricdruid.net/images/lfo/TapCircuitV1.gif . with a metronome feeding the external sync input. I'm guessing input wants to see more of a squared pulse, than a quick peak. The amplitude is ok, but I wonder how we can make it look like more of a pulse...

A monostable multivibrator would probably do it.

Depends on how the speaker is driven.  If it's DC coupled to the output drivers, then it can have DC offset.  If it's AC coupled, it will remove DC offset.  And for that matter, no two different metronomes will have the same output.  I highly doubt there's a standard metronome click sound that the industry uses.  Color me lazy, but I'd just build a simple 555 oscillator and use that for my trigger instead of trying to make a metronome work.  

Still, I bet most cheap metronomes just have a quick pulse like this one. It's easier than generating a tone and it works.

Depends on how the speaker is driven.  If it's DC coupled to the output drivers, then it can have DC offset.  If it's AC coupled, it will remove DC offset.  And for that matter, no two different metronomes will have the same output.  I highly doubt there's a standard metronome click sound that the industry uses.  Color me lazy, but I'd just build a simple 555 oscillator and use that for my trigger instead of trying to make a metronome work.  

Take a look at the video. The signal is mostly at 0V, but there are pulses at 6V. So there is effectively a slight DC offset. Also, there would be an 'overshoot' as the capacitor discharged after the pulse.

It would probably come out looking like this:

[YouAre]

Don't understand your point.  Of interest would be the frequency of a typical metronome signal, the duration, and any decay (envelope).  The metronome headphone jack is also an audio output signal without any DC offset, is it not?

Mainly the duration of ever "click" and the decay. I'm wondering, how can I increase that envelope? I haven't yet forayed into envelope controllers, so any suggestions of circuits to check out would be greatly appreciated!

Depends on how the speaker is driven.  If it's DC coupled to the output drivers, then it can have DC offset.  If it's AC coupled, it will remove DC offset.  And for that matter, no two different metronomes will have the same output.  I highly doubt there's a standard metronome click sound that the industry uses.  Color me lazy, but I'd just build a simple 555 oscillator and use that for my trigger instead of trying to make a metronome work. 

That's not lazy, that's involved! My idea is to use a metronome as an alternative to tap tempo. And yes, you're right. No 2 metronomes are the same, just as no 2 guitar/pickups are the same. I'll adjust the circuit for different inputs.

[defaced]

That's not lazy, that's involved! My idea is to use a metronome as an alternative to tap tempo.

To each his own.  But dumb question, doesn't the device you're trying to control with tap tempo have an LFO and a speed control already?  I don't see how using a metronome is any different than an LFO in an effect from what you're describing. 

[YouAre]

To each his own.  But dumb question, doesn't the device you're trying to control with tap tempo have an LFO and a speed control already?  I don't see how using a metronome is any different than an LFO in an effect from what you're describing. 

It does. But, I practice to a metronome. So having the LFO locked to that would be much better in my eyes. The TAPLFO can use an external sync to trigger the LFO. Using a metronome so that you're perfectly in time would be pretty awesome.