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FrozenGate by Avery

How to Build Home Made Laser Power Output Meter

  • Thread starter Thread starter yew.sir-name
  • Start date Start date
Re: How to Build Home Made Laser Power Output Mete

I'll tell you what - if I cannot explain it, I'll find someone who can ! ;D ;D

Okay, basically - an ND-8 filter is a "Neutral Density" filter. It is an attenuating filter, in that it only lets a set amount of light to pass through it. You can use a bottle of olive oil as an attenuating filter if you want - as long as it reduces the amount of optical power transmitted through it, you are okay ! I am not certain exactly what the "8" in ND-8 stands for - but as long as you know the output of a laser - say it truly IS a 50mw laser.......and when you shine it through the attenuating filter, you get a reading of 25mw, you know that it blocks 50% of transmitted light. See what I mean yet ? So - pop over to a camera store - or Walmart, even - grab ANY Nuetral Density filter - make certain it is almost as dark as possible - and after you measure the laser once WITHOUT the filter, then you can measure it WITH the filter, and figure out the difference. I hope all that rambling makes sense ?
 





Re: How to Build Home Made Laser Power Output Mete

Ok that works all well and fine for something that I have that is below the threshold on the laser meter. Something that can be tested prior to putting the nd8 filter in there. Once that's done it's a matter of figuring what is left when the filter is in place. However. Since I do not have any lasers that are low enough to work on the meter without a filter I'm incapable of testing it properly. Looks like I'm gonna have to buy another leadlight. Sorry senkat your not getting your money for the laser I bought from you as it's going to a leadlight for testing purposes. I'm kidding. I will just send the power meter to you for tinkering with. Oh waitaminute. I just remembered your sending me that 50mw DX (newwish) too. What was the output power on your meter from that laser?
 
Re: How to Build Home Made Laser Power Output Mete

Ok the third wire is for a shunt resistor in case you need it. it comes with detailed spec sheet. this is what they claim
"Silicone PIN diode sensor capable of handling a 100mw beam with no damage."
 
Re: How to Build Home Made Laser Power Output Mete

Kenom said:
Ok the third wire is for a shunt resistor in case you need it. it comes with detailed spec sheet. this is what they claim
"Silicone PIN diode sensor capable of handling a 100mw beam with no damage."
Click to expand...
Are you talking about the one on ebay? If so did I miss something? it only goes to 50mw.
 
Re: How to Build Home Made Laser Power Output Mete

Yes the one on ebay. I asked what happened if it was over 50mw would it damage the unit. and they claimed it would not be damaged by anyhting up to 100mw but woudl not be capable of interpreting the output power of anything over 50mw. He was actually kind of a jerk. I will post his response to my last batch of questions. I asked him if it was capable of not being fried by a 100mw laser why wasn't it possible to test that high. I also asked how one would use such device to measure over 100mw into the 200mw range. His response to that was... (hey can I get in trouble for posting a comment from an email? at CPF i've seen the mods get mad cause of posting without someone's permission) Well, We will find out won't we.

Hi,
if you read the auction listing... it says....


The Laser Power Module was designed to let the hobbyist technician know
the output power of any Lasers from 400nm to 1100nm.


Can check Lasers from 0.1mW to 50mW output power in 0.1mW increments.

It has been tested and calibrated for the above specs.

If... for instance... you shine a 100 Watt laser on a sensor designed
for
200mW then you would definitely burn that sensor.
What we are saying is that a 100mW laser will not burn the Sensor of
our
Calibrated Laser Power Meter Optical Sensor Head Module.

If you need to check lasers up to 200mw then you need to spend a lot
more money than what we are asking for this item and buy a commercial
Laser Power Meter.
 
Re: How to Build Home Made Laser Power Output Mete

Kenom said:
Yes the one on ebay. I asked what happened if it was over 50mw would it damage the unit. and they claimed it would not be damaged by anyhting up to 100mw but woudl not be capable of interpreting the output power of anything over 50mw. He was actually kind of a jerk. I will post his response to my last batch of questions. I asked him if it was capable of not being fried by a 100mw laser why wasn't it possible to test that high. I also asked how one would use such device to measure over 100mw into the 200mw range. His response to that was... (hey can I get in trouble for posting a comment from an email? at CPF i've seen the mods get mad cause of posting without someone's permission) Well, We will find out won't we.

Hi,
if you read the auction listing... it says....


The Laser Power Module was designed to let the hobbyist technician know
the output power of any Lasers from 400nm to 1100nm.


Can check Lasers from 0.1mW to 50mW output power in 0.1mW increments.

It has been tested and calibrated for the above specs.

If... for instance... you shine a 100 Watt laser on a sensor designed
for
200mW then you would definitely burn that sensor.
What we are saying is that a 100mW laser will not burn the Sensor of
our
Calibrated Laser Power Meter Optical Sensor Head Module.

If you need to check lasers up to 200mw then you need to spend a lot
more money than what we are asking for this item and buy a commercial
Laser Power Meter.
Click to expand...
Interesting, because I was told you can push the sensor to 60mw and no more; but probably could use a filter for higher power measurements. I ordered my unit 4 days ago and should be here soon, we shall see. I have numerous 5mw red & greens to test with, plus many other high power lasers 10mw, 50mw, 150mw, 200mw, etc So I think I'll have plenty to test with and give this thing a run for my money.
 
Re: How to Build Home Made Laser Power Output Mete

Hmm. should be interesting to see your results. I also purchased one and am anxious to see how it works with a ND filter for measuring lasers over 50mw as my green LED hooked up to a multimeter just doesn't cut it. Although I'm inclined to believe that it is at least a small amount accurate and gives you a ballpark estimate of your lasers output power.

Say for example I have a 5mw leadlight I've just modified. it is now putting out somewhere in the range of 10-100mw and using the LED to give you a ballpark figure. it's testing around 34-45mw. Well, at least I know it's not 100.
 
Re: How to Build Home Made Laser Power Output Mete

Kenom said:
Hmm. should be interesting to see your results. I also purchased one and am anxious to see how it works with a ND filter for measuring lasers over 50mw as my green LED hooked up to a multimeter just doesn't cut it. Although I'm inclined to believe that it is at least a small amount accurate and gives you a ballpark estimate of your lasers output power.

Say for example I have a 5mw leadlight I've just modified. it is now putting out somewhere in the range of 10-100mw and using the LED to give you a ballpark figure. it's testing around 34-45mw. Well, at least I know it's not 100.
Click to expand...
Yea I tried the LED method & wasn't pleased, but your right it gives you atleast an idea. I'm going to use a ND8 filter with anything over 10mw that I have and see how it goes. I then will compare it against a Coherent Lasercheck starting with the 5mw unit and see how the accuracy goes, will post back here when I've done all of that.
 
Re: How to Build Home Made Laser Power Output Mete

Will be looking forward to your results. Where did you get your filter? is it small or large? I need to know where I can get one of my own for testing of my lasers over 100mw. Was hoping to get my BFG in the mail today but nogo.
 
Re: How to Build Home Made Laser Power Output Mete

one thing to keep in mind is that there may not be a linear relationship between laser power and filter attenuation.  For example, a higher powered laser may have more "transmission" than a lower powered laser.  

You can't assume all ND8 filters are equal - they aren't.  One ND8 filter I bought off e-bay blocks most 808nM radiation (take the reading from the meter and divide it by 31) but the ratio for 532nM is around 10.  

So, not only may readings vary between different filters, but also between different power levels and between different wavelengths...  Claibrating one of these takes some time and work.
 
Re: How to Build Home Made Laser Power Output Mete

crap! I was hoping to make it simple.
 
Re: How to Build Home Made Laser Power Output Mete

I'm not trying to dash your hopes. - There MAY be a linear relationship in all these factors, you just can't assume there is.  The simplest way is to build one and test it agains lasers of known power and against another meter.  

I think this is a great idea and if you need me to help, I have a meter and about a dozen lasers of differnt power.  I'll run some side by side tests for you and send it back or forward it to senkat for further testing or vice versa... :).

also, be sure to get a glass filter
 
Re: How to Build Home Made Laser Power Output Mete

DEFINITELY a glass filter ! Don't get caught in the same boat as "WE" were...the "WE" being al those that bought the LPM-1 laser power meter from Andover Holography....we were sent plastic ND-8 filters....but he made it right by locating some glass filters, and re-calibrating it for free....
 
Re: How to Build Home Made Laser Power Output Mete

SenKat said:
DEFINITELY a glass filter ! Don't get caught in the same boat as "WE" were...the "WE" being al those that bought the LPM-1 laser power meter from Andover Holography....we were sent plastic ND-8 filters....but he made it right by locating some glass filters, and re-calibrating it for free....
Click to expand...
Yea I got a Optical Glass ND8 filter. (figured plastic would melt) 8-)
 
Re: How to Build Home Made Laser Power Output Mete

Alright. SenKat says he likes math. I hate math so I'm puttin this baby in his hands or yours. I havn't even really won the bid on the module yet but I'm sure I will. SenKat has already taken a look at the .pdf that they send out with it and it claims there is a bit of error involved with it as there is also a bit of math that needs to be done for different wavelengths. I'm not too particularly impressed with this unit and if I don't win this one the next thing I'm saving money up for is a Coherent Lasercheck. I want something with certainty not ballpark. I've got a LED that gives me ballpark.
 
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