Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

weird lpm idea.

kiyoukan

kiyoukan

0
Joined
Oct 24, 2009
Messages
2,555
Points
48
I had an idea to make a very weird lpm using this.
Radiometer
base_media

I have had one of these for years.
Simple idea turn on laser wait for 30sec till it gets to max speed then record the rpm.
Now i know to make this right its box must be a non reflective black coating and the hard part would be finding a way to get the rpm.
I was thinking some sort of optical encoder or photo diode.
by pointing the laser to the outer edge of the squares as it spins it will blink the light and make some sort of counter.
Then the rest would be math and need of a real lpm to make the calculations but it is an interesting idea.
Any thoughts? this is more of a fun experiment than a perfect solution but i cant resist the faster it spins the more power you got!.
:D
in theory as long as you did not burn the metal and put some sort of filter on the rpm reader you could measure any power level.
 
Last edited:





lasersbee

lasersbee

0
Joined
Sep 20, 2008
Messages
17,622
Points
113
I've already posted that idea quite a while ago...
I'm sure it can be done... but accuracy will be difficult
and as I always state.... You will need a calibrated LPM
to calibrate it... :cool:

Jerry
 
kiyoukan

kiyoukan

0
Joined
Oct 24, 2009
Messages
2,555
Points
48
what would be the best a photo diode or a optical encoder? or both just depends on the quality?
 
Benm

Benm

0
Joined
Aug 16, 2007
Messages
7,896
Points
113
Sounds like a fun experiment, but i dont expect a linear or even well predictable relationship between power and rpm. I wonder how much power would be required to set it in motion at all.
 
lasersbee

lasersbee

0
Joined
Sep 20, 2008
Messages
17,622
Points
113
Just did a few experiments with a Radiometer and it takes ~45mW to
start turning the vanes...
The other problem is that the black coating on the vanes will burn if
the lasers beam is not expanded whe using higher powered Lasers...


Jerry
 
kiyoukan

kiyoukan

0
Joined
Oct 24, 2009
Messages
2,555
Points
48
interesting. so it has a 45 mw min? i would have expected it to be a bit lower.
well then at least i know all my lasers are above 45 mw lol.
Because they all push that thing like crazy.
 
Benm

Benm

0
Joined
Aug 16, 2007
Messages
7,896
Points
113
I suppose that varies greatly between individual radiometers though.

Too bad more powerful lasers burn the paint off though. Once it's moving it should be so bad since the beam gets spread over a line and between the vanes.
 
kiyoukan

kiyoukan

0
Joined
Oct 24, 2009
Messages
2,555
Points
48
but if you diverge the beam so its not a super intense spot but still fitting on the vanes it should work. or just put a 50% filter on the laser to reduce its power.
 
HIMNL9

HIMNL9

0
Joined
May 26, 2009
Messages
5,318
Points
0
Burn the black paint off ? ..... mine works better shining the beams on the silver faces, instead on the black ones ..... (but i have only a small radiometer, big ones probably works better)

I had also planned to make a base for it, take 3 modules, 100mW red, 50mW green and 120mW blue, place them in the base at 120 degrees one each from the other, shining diagonally to the faces ..... tried it without the base, for see how it was working ..... nice result, but too dangerous, cause in this way the beams reflects randomly anywhere, when the mill spin .....
 
Benm

Benm

0
Joined
Aug 16, 2007
Messages
7,896
Points
113
I suppose it would put out a nice show, but its too dangergous indeed - those vanes seem like decent mirrors so you get collimated beams in more or less random directions.

As a display piece it might help to unfocus the lasers somewhat so that you get rather large dots of light shining around instead of dangerous thin beams.
 
Cyparagon

Cyparagon

0
Joined
Sep 12, 2007
Messages
9,399
Points
113
Mine must be broken. Even my 400mW IR pointer doesn't turn mine, although it does burn the paint ??
 
lasersbee

lasersbee

0
Joined
Sep 20, 2008
Messages
17,622
Points
113
My Radiometer vanes are Black on one side and White on the
other side..
I would think that all Radiometer manufacturers don't use the
same identical products to make the vanes or paint them...
I would think they also don't use the same vane dimensions...
which may change the RPM between Radiometers for the same
light energy input..

BTW... using a 200mW Red Dilda I can make the Radiometer spin
quickly shining on the Black side of the vanes... but I can't make it
spin at all shining the Laser on the White side...:thinking:


Jerry
 
Last edited:
HIMNL9

HIMNL9

0
Joined
May 26, 2009
Messages
5,318
Points
0
Probably due to the quality and/or suspension efficence .... don't really know .....

I have one at home that spins also pointing the beams on the white/silver faces, but it need at least 50mW, otherwise don't move ..... it's one of the cheap models sold as "toy / display / dust-collectors" (LOL), and the suspension is simply a sharp needle holding a glass "vial" ..... and we had a bigger one, in the school physic lab, that was spinning also just placing the hands around it, but that one was a professionally lab made with sapphire suspension, and i never found a cheap one around with the same efficency (and don't know how much it can cost, one like that one :p)
 
You must log in or register to reply here.





Top