Laser based oscilloscope

[MihaiG]

Hi,

This is a laser based oscilloscope for my AP Physics summative,

here is a small pic of the device drawing a 150Hz sin wave



i will post more pictures in a while, (high quality ones)

it works on a very simple basis

a "modded" $1 laser diode to increase the brightness(amperage).

it emits light that bounces of a mirror that is attached directly to the driver/membrane of a speaker this then reflected perpendicular to the ground (up the tube) and is then split into a circle by a spinning motor with a mirror attached to it.

also the mini screen can be removed to project the laser on wall, but it doesnt work well since intensity is lost over distance


the potentiometer for the motor to regulate speed



the spinning mirror



showing the speaker with the mirror on it



showing the mp3 player plugged into the device

C&C are welcome,

[PaulButler]

Wow, that's pretty cool. Is it similar to how a real oscilloscope works? I always thought it had more to do with magnetism.

Are you using two mirrors? Is one connected (glued?) directly to the speaker, or what?

[MihaiG]

um a real oscilloscope fires a beam of electrons on a phosphorus coated screen, like a tv i think


ya the bottom mirror which the laser first bounce off on is glued with a piece of metal (slightly springy)to the driver of the speaker

[Skynet]

MihaiG @ Sun May 13, 2007 9:09 pm wrote:

um a real oscilloscope fires a beam of electrons on a phosphorus coated screen, like a tv i think

Yeah, the older ones are just very simple cathode ray displays. Like PaulButler said, they use magnets. (to steer the electrons) New ones are just "plain old LCD displays"

[PaulButler]

MihaiG @ Sun May 13, 2007 9:09 pm wrote:

um a real oscilloscope fires a beam of electrons on a phosphorus coated screen, like a tv i think


ya the bottom mirror which the laser first bounce off on is glued with a piece of metal (slightly springy)to the driver of the speaker

In that case, your design is quite clever. Did you come up with it?

[MihaiG]

not really, my dad gave me the idea, but there variations on the internet that use a hardrives read write head as the moving mirror, which ive tried and is pretty nifty,

but this is still pretty cool

only thing it only displays low freequencies well


ill see how wwell the hard drive based one displays high frequencies


i have two old oscilloscopes in my basement suckas