445nm connection problems and strange sound

[532 with Envy]

Okay, later on I might try to record a video of what I am experiencing, I haven't posted video before though.

This is a little hard to explain but a very strange effect.

I have my bride of frankenstein build that is all DIY...
for lookin'at... http://laserpointerforums.com/f42/bride-frankenstein-58519.html

Now the battery connection is through twisting the end cap to make contact, as of late I have notice that it emits a quiet high pitched sound when "ON". This hasn't really bothered me and I still play with it from time to time, Even at the low power its running, at the focal it still burns.:evil:

Tonight I'm playing with it, the quiet high pitched sound is happening, I put it to a close focal, slide a match book in front and it begins to burn like usual, what I do notice is that the sound coming from the host begins to 'modulate'(sorry not sure how to explain), either way I would expect the sound to stay steady because of some battery connection trouble, but NEVER to change because the beam is breaking(burning carboard)!

I tried it a few times and get the same result, steady quiet high pitch sound, then when I break the beam at burning point, focal, the tone changes?:undecided:

This is curious! Anyone lend some light on this I would be interested.
Thanks:beer:


Edit: just wanted to try it again to make sure i'm not posting something crazy..I though perhaps I was shaking it around in my hand. I put it down on a cloth and moved the matchbook back and forth and still had the same result. The sound is very faint, I may not be able to catch it on video, but it sounds almost like harmonics(my ear is trained more to music than science though)

 

[daguin]

Try having someone else place the match into the beam while you look away (with your eyes closed) and listen without moving your head.

Peace,
dave

 

[532 with Envy]

It could be my perception and an environmental condition, but it still seems like a reaction perhaps from reflections. Also it may not matter but I am using the matchbook and not match.

I ran it by my roommate, he heard the same sound change. I listened as an outside observer and the same. It only happens when the book hits the right spot, anywhere outside and the sound is steady.

 

[daguin]

My gut feeling is still observer movement/bias.

However,it may also be that you are hearing the sound "echo" off of the matchbook/hand/arm or that the position of the matchbook/hand/arm is changing the acoustics of the area.

Peace,
dave

 

[GoRdOn_B]

i have a phr build in a leadlight that makes a high pitched sound when i turn it on. i dont know what it is that makes it do that. but i do know what your talkin about

 

[532 with Envy]

...@Dave..I understand what your saying, and that would hold true to the sound change coming at the focal point.
I did put it on the table and just move the book back and forth in attempts to eliminate a variable with the same results.
I should mention that the 'echo'/sound is in sync with the flashes of burning.(i'm not doing well explaining this..sometimes even the sublime is hard to put into words)

So, being said it may be a sound "echo", would it be the lights reflection that is creating the 'echo'?

 

[532 with Envy]

i have a phr build in a leadlight that makes a high pitched sound when i turn it on. i dont know what it is that makes it do that. but i do know what your talkin about

I think it's a loose battery connection of sorts, at least that's probably what it is in my case. My connection isn't really 'sound', but it works.:beer:

 

[lazeerer]

I am almost certain that it is the protection circuit of the battery. I have also read somewhere but cant remember exactly that a high pitch noise usually comes from the inductor as well. But i dont know the explanation for it.

I have had this high pitched nose before coming from one of my protected 14500 cells when i was trying to suck to my juice out of it.

If you wish i can try to attempt it to make this sound and record a video and maybe this can help you hear what mine sounds like and compare it to your sound.

Iam not certain i can get it to make the sound i will have to hook it up.

Let me know.

 

[532 with Envy]

I am almost certain that it is the protection circuit of the battery. I have also read somewhere but cant remember exactly that a high pitch noise usually comes from the inductor as well. But i dont know the explanation for it.

I have had this high pitched nose before coming from one of my protected 14500 cells when i was trying to suck to my juice out of it.

If you wish i can try to attempt it to make this sound and record a video and maybe this can help you hear what mine sounds like and compare it to your sound.

Iam not certain i can get it to make the sound i will have to hook it up.

Let me know.

Thanks for the offer, I'm not really worried about the sound and probably won't fix it. The unit is running at pretty low power and that might explain it somewhat.
I was more interested in the sounds change at focal and I think that Dave and I have worked out at least a very plausible explanation. Aside from some strange feedback through the diode from the reflection(not even sure it that could happen) and environmental effect might be whats going on.

 

[lazeerer]

OK. I am glad you guys got it to a plausible explanation as i dont even know what to say on that part.:thinking:

It is very strange.

 

[BShanahan14rulz]

You're absolutely certain that the sound is coming from the actual laser and not the focal point? I see you've already ruled out that weird noise you sometimes "hear" if you looking at something bright...Hopefully it's not the laser diode chip acting as feedback and causing electrical characteristics to change in the diode. Most squeals come from inductors.

The only other alternative that I can think of is that when you have a laser focused like that and force something into the focal point, the chip weevils that are residing on that object create a high-pitched squealing as the focal point sterilizes the surface. Rest assured, these chip weevils cannot harm your laser if they aren't being sterilized, but it is very possible that the heat will make one of them jump towards your laser diode's chip.

 

[DTR]

I am with 532. Normally when I hear a high pitch sound when turning a laser on it is from a weak connection point somewhere in the host. I would try bypassing the tailcap and see if that helps.

 

[RA_pierce]

I've had a few Flex Drives make a high pitched "squeal." I diagnosed the problem as insufficient battery power and in another laser it was due to a poor solder joint at the - battery contact. The other time it was due to a crappy switch. When the laser would squeal it would drop in power and sometimes flicker.
So, in all these cases it was just something wrong with the electrical continuity.

 

[Benm]

My gut feeling is still observer movement/bias.

However,it may also be that you are hearing the sound "echo" off of the matchbook/hand/arm or that the position of the matchbook/hand/arm is changing the acoustics of the area.

I doesn't have to be though. I've done some experiments with pulsed operation and burning, and in some rare instances i could hear the pwm frequency (that was in the kHz range) coming from the target. I suppose this is somehow caused by the material slightly cooling and heating up between the pulses.

I found it difficult to reproduce the effect though, but those experiments were all done with less powerful reds.


The whole situation is likely to be caused by a bad electrical connection, that produces a sound of its own (a spark on every time it disconnects). The frequency could be the same as that of the driver - those draw current in peaks too, resulting in variable load on the bad connection.

 

[chipdouglas]

also i know this is far fetched. but are you running an inverter any where near where you are using your laser. they tend to hum quite loudly.

michael.

 

[532 with Envy]

I doesn't have to be though. I've done some experiments with pulsed operation and burning, and in some rare instances i could hear the pwm frequency (that was in the kHz range) coming from the target. I suppose this is somehow caused by the material slightly cooling and heating up between the pulses.

I found it difficult to reproduce the effect though, but those experiments were all done with less powerful reds.


The whole situation is likely to be caused by a bad electrical connection, that produces a sound of its own (a spark on every time it disconnects). The frequency could be the same as that of the driver - those draw current in peaks too, resulting in variable load on the bad connection.

It is an interesting phenomena, there has been much discussion of the bad electrical connection and i'm sure that is what is producing the high pitch sound(the build is very low budget:shhh
The change in sound when I broke the beam at the right point is what really interested me.
I understand what Dave is saying and would agree with him in part, but my gut was telling me that it had something to do with the change in beam characteristics.....or something(i'm by no means a physics professor!).
It's been fun to see what people have to say about it, i'm afraid that the sound and it's change from what i'm hearing is so faint it would be hard to capture it on video. I did run it by a roommate and he heard the same change when the beam hit the burning point.
Perhaps this weekend I will "Try" to capture it and share it here.:beer: