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

# How to Build Home Made Laser Power Output Meter

Y

#### yew.sir-name

##### Guest
while googleing i found plans for a laser meter, it's cheaper to make one than spend hundreds on buying one

www.cat.ernet.in/others/lasinfo/p-meter.html

www.blueskymarketing.co.uk/mega_green/laser_tech.htm

there must be good reasons why nobody has made one here, or have they? just wondering what the reasons are, say you only wanted to know howmuch visible light was coming out the end of your laser this thing would be perfect, no? the same plans with an ir photodiode would also measure howmuch ir is coming out your laser?

any input would be appreciated

(edit)

i've been informed that the second link is equivalent to using a light meter to record the laser output - and that will not work so well... also the pictures are not in the right order. 1 is 5, 3 is 1

how well is not so well compared to a regular laser check like a coherent? is it a huge difference?

Timelord

#### Kenom

##### Well-known member
Re: How to Build Home Made Laser Power Output Mete

Both SenKat and I are going to be working with some photodiodes to see if we can actually get something like the first one to work as a laser power meter. I have the photodiode that I pulled from my DX30mw. If the photodiode can be used to measure the output power of the laser and turn down the current with the APC then you should be able to use the exact same thing for measureing output power of a laser. Just take the time to figure the math.

Y

#### yew.sir-name

##### Guest
Re: How to Build Home Made Laser Power Output Mete

Ah mathematics, tis the bane of us all, i was reading ways to calculate visible light intensity and got a headache. I look forward to finding out your outcome

i cant wait till i get my dx 30, maybe on finding out your results it will enable some kinda mod where the output could varied, like with a slide bar variable resister to take it down to <5 and upto the dx advertised <200, (like the pot mod but more sexy and always accessible) they're the same laser (500mw samsung diode) just with different chips on the board?

#### stevetexas

##### New member
Re: How to Build Home Made Laser Power Output Mete

the IR diode may be the same, but the crystals make a HUGE difference. The ones with the best crystals will sell for more because they can more efficiently convert the IR output to green.

#### Kenom

##### Well-known member
Re: How to Build Home Made Laser Power Output Mete

yeah what he said.

I was gonna say the same thing. I've learned through others telling me that pumping too much ir into a lower quality set of crystals makes smoking crystal goo. Now as much as I would like to see this. I do NOT want to see it in my expensive laser pointer.

S

#### SenKat

##### Guest
Re: How to Build Home Made Laser Power Output Mete

Agreed, and I do not think the DX200's have a 500mw pump diode - that would be a crazy high efficeincy ratio, and super fine crystals - they would sell for QUITE a bit more ! I believe the DX200's have a 1.2 or 1.5Watt 808nm pump diode in there - most likely C-mount in order to get teh power/efficeincy ratio up there !

Y

#### yew.sir-name

##### Guest
Re: How to Build Home Made Laser Power Output Mete

yeah i didnt think about the crystals, i don't want a gooey laser.  i have another question a little off subject...

i was reading on the forum about a 200mw ir diode for \$30, (23 us) and i seen on the same site a focusable 200 ir diode for about 47us  (probably the same diode in a case to focus it) hxxp://secure.oatleyelectronics.com//product_info.phpcPath=27&products_id=579&osCsid=b108b3af739950efe56d579e3a74d9cb ...

so if i replaced the diode for one out of a dx 200 i'd have a 1.2-1.5 wat focusable ir laser for pretty cheap? and no goo because no crystals! or at the minimum a 500mw ir focusable laser if i get the dx 5mw green, and a spare 200mw diode. plus spare crystals to turn into goo, or just swap the diodes over and have no spares and no goo.

also while browsing i came across another link on the forum for an ir burning diode, hxxp://cgi.ebay.com/HIGH-POWER-BURNING-LASER-DIODE-IR-OPTICS-MODULE-UNIT_W0QQitemZ290076456298QQihZ019QQcategoryZ4661QQrdZ1QQcmdZViewItem

the picture shows a white light on the surface it's pointing to, i thought ir was invisible? or does it have something to do with that particular diodes wavelength?

to keep it on subject what  kind of laser check would i need to accurately measure 1.5 watt of ir, surely 1.5 watt of focused ir would melt a home made laser check?

#### picrthis

##### New member
Re: How to Build Home Made Laser Power Output Mete

Check on fleebay, there is a guy that is already selling them from Canada. His only goes to 50mw, but you could put a density filter in front of the sensor just like everyone else selling meters below \$500.00 does.

Y

#### yew.sir-name

##### Guest
Re: How to Build Home Made Laser Power Output Mete

picrthis said:
Check on fleebay, there is a guy that is already selling them from Canada. His only goes to 50mw, but you could put a density filter in front of the sensor just like everyone else selling meters below \$500.00 does.
this is the thing you're talking about

looks like a photodiode in black tape to me. similar to ww.blueskymarketing.co.uk/mega_green/laser_tech.htm . though i've no idea what the battery would be for. how does this differ from the one on that page? as for the density filter what would that do to it? increase its ability to measure beyond 50mw?

S

#### SenKat

##### Guest
Re: How to Build Home Made Laser Power Output Mete

The ND filter, or Neutral Density filter cuts off a large amount ot hte laser light reaching the array. So - if it is a filter that cust out 50% of light going through it, you can double the power to 100mw, etc....etc..

#### picrthis

##### New member
Re: How to Build Home Made Laser Power Output Mete

yew.sir-name said:
[quote author=picrthis link=1179663591/0#7 date=1179958996]Check on fleebay, there is a guy that is already selling them from Canada. His only goes to 50mw, but you could put a density filter in front of the sensor just like everyone else selling meters below \$500.00 does.
this is the thing you're talking about

looks like a photodiode in black tape to me. similar to ww.blueskymarketing.co.uk/mega_green/laser_tech.htm . though i've no idea what the battery would be for. how does this differ from the one on that page? as for the density filter what would that do to it? increase its ability to measure beyond 50mw?[/quote]
They are one in the same.

Y

#### yew.sir-name

##### Guest
Re: How to Build Home Made Laser Power Output Mete

the filter now makes sense, as for spending money on a photodiode in black tape, that's bad advice considering the plans to make one for pennies is a click away. the dude on ebay must be cleaning up

T

#### timelord

##### Guest
Re: How to Build Home Made Laser Power Output Mete

Y

#### yew.sir-name

##### Guest
Re: How to Build Home Made Laser Power Output Mete

Timelord said:
wouldn't mind finding out myself if it's any good, and why it needs a 9v battery.

T

#### timelord

##### Guest
Re: How to Build Home Made Laser Power Output Mete

Good question 9v is a lot of juice going into such delicate components...

S

#### SenKat

##### Guest
Re: How to Build Home Made Laser Power Output Mete

eh - that's not too bad....it looks like a simple design - I may order one to try out - and if it doesn't work properly, I can send it back to him