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Laser display made in 15 minutes (video)






That's pretty cool looking, you should throw some fog or smoke in with it.
 
Very nice would like to see pics of the build itself.
Your on you way to the laser addiction as far as laser shows.
I started with a very similar thing but i was never satisfied even now with galvos i kinda want more.
 
"Like um looking at a microscope and...like watching molecules dance arround...dance dance dance dance!" God...that's the funniest, yet most redonculous thing I've heard in a while! LAMO!!!
 
Somehow i suspect they are on more than just alcohol ;p
 
Tech_Junkie said:
How about a "How to" post?
Click to expand...

We essentially built a rectifier. I'm new to electronics and I don't know the formal language for things in the field of electronics, but I think a lot about how to accomplish tasks. My friend is an electrical engineer.

I basically proposed the idea to make A/C current useful to a D/C motor via cheap silicon diodes. I wanted take the not useful (negative direction current) and negate it so it wouldn't adversely affect a D/C motor. I basically had half of it, and he pointed me to a schematic of people that apparently had done this before... even taking the negative and redirecting it to positive voltage.

It's basically 4 diodes wired in series, then the power supply is connected to points between the diodes to achieve a D/C current out of the music amplifier's A/C voltage. The amplitude is proportional to the D/C motor movement, and you can titrate the motor movement with the volume knob. I'm relatively certain you can buy something for this, but we built it ourselves.

You can mount optics, mirrors, springs, and whatever the hell else you want on to the motor and control the effect yourself.
 
rectifier_bridge.gif


So you just put the signal from the stereo through a rectifier? I'm surprised there was enough current to move the motor, must be some stereo! What did you use as the mirror on the motor?
 
Jayls5 said:
We essentially built a rectifier. I'm new to electronics and I don't know the formal language for things in the field of electronics, but I think a lot about how to accomplish tasks. My friend is an electrical engineer.

I basically proposed the idea to make A/C current useful to a D/C motor via cheap silicon diodes. I wanted take the not useful (negative direction current) and negate it so it wouldn't adversely affect a D/C motor. I basically had half of it, and he pointed me to a schematic of people that apparently had done this before... even taking the negative and redirecting it to positive voltage.

It's basically 4 diodes wired in series, then the power supply is connected to points between the diodes to achieve a D/C current out of the music amplifier's A/C voltage. The amplitude is proportional to the D/C motor movement, and you can titrate the motor movement with the volume knob. I'm relatively certain you can buy something for this, but we built it ourselves.

You can mount optics, mirrors, springs, and whatever the hell else you want on to the motor and control the effect yourself.
Click to expand...

Nice effects...:cool:

It is called a Bridge Rectifier.... and if you put a 100uF to 4000uF capacitor
of the proper voltage across the output you will see an increase in voltage
to your motor...

I would have thought that your Engineer friend would have known that...:whistle:

Jerry
 
Last edited:
Pontiacg5 said:
rectifier_bridge.gif


So you just put the signal from the stereo through a rectifier? I'm surprised there was enough current to move the motor, must be some stereo! What did you use as the mirror on the motor?
Click to expand...

That's pretty much the schematic there. Very simple 4 diodes wired in series together like I said.

The motor was pulled from a side view mirror on an old ford explorer. The reflector was just a piece of broken CD. We mounted it to a spring of a pen for added wobble.

lasersbee said:
Nice effects...:cool:

It is called a Bridge Rectifier.... and if you put a 100uF to 4000uF capacitor
of the proper voltage across the output you will see an increase in voltage
to your motor...

I would have thought that your Engineer friend would have known that...:whistle:

Jerry
Click to expand...

He does know that. I was just speaking from my personal perspective. I was under the impression that capacitors have the tendency to reduce changes in voltage along a circuit, so I don't really understand how a capacitor would increase voltage rather than smooth it...

In either case, a home amplifier powers small DC motors fine. You can use each speaker output to power a different motor that does a different effect. You can even put an equalizer (or filter) inline so it only responds to the frequency range you desire. Simple stuff but produces neat effects.
 
lasersbee said:
Nice effects...:cool:

It is called a Bridge Rectifier.... and if you put a 100uF to 4000uF capacitor
of the proper voltage across the output you will see an increase in voltage
to your motor...

I would have thought that your Engineer friend would have known that...:whistle:

Jerry
Click to expand...


I'm genuinely curious how a cap would increase voltage rather than what I described. Could you explain this to me?
 
I second Jay's question, as far as I know you cannot rely on just a capacitor to increase the voltage going through a circuit. You CAN hook up capacitors in series to increase maximum working voltage, but that is completely irrelevant.

Regards,

amk
 
Electronics 101:

A capacitor behind the bridge rectifier will increase the -average- voltage going to the load, in this case making the motor run faster.

Without the capacitor, the output from the bridge rectifier are a series of half-sine waves between zero volts and the peak voltage. If you put a capacitor over the output that will charge to the peak voltage, and power the motor while the voltage from the bridge is below peak. When it hits the next peak, the capacitor will be recharged.

The capacitor needs to be big enough to make the voltage drop due to it discharging into the motor small. Also, the transformer must be able to supply the peak current at the top of each sine wave - mostly not a problem with small systems.
 
Here is a quick picture to try to explain it a little better.

The black line would be your voltage, the capacitor will store the voltage and dissapate it over the low spot as the voltage switches over. The bigger the capacitor the longer it can cover and "fill" the hole. The green lines in this picture are voltage after capacitors, and the capacitors are getting bigger the further right you go.

sinewave.jpg


Its a crude drawing, but I think it gets the point across. The capacitors won't increase voltage, but help make it more uniform at a higher voltage than it would be without them.
 
OK that makes sense. I am aware of how components in an electric circuit work, I was just under the impression that the one post was saying "if you stick a cap across a 3v output (i.e.) you get 6v" sort of thing.

Thanks,

amk
 
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