Laser pointer discussion. Read/write reviews of laser pointers and laser pointer companies. Learn about all types of laser pointers and lasers





Welcome to Laser Pointer Forums! If you are looking for a laser pointer or want to compare different laser pointer companies, you may want to check out the LPF Laser Pointer Company Database. The link will open in a new window for your convenience.








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes
Laser Technology Laser Pointer Parts Lasers by Wavelength
Top 10 Laser Pointer Companies Laser Pointer Company Database Visible Beam Laser Pointers


One laser store meets all your needs

























Go Back   Laser Pointer Forums - Discuss Laser Pointers > Lasers > Tutorials, Help & Repairs



LPF List of Laser Pointer Companies (link opens new window)



Reply
 
LinkBack Thread Tools Display Modes
Old 08-26-2011, 05:54 PM #1
axs axs is offline
Junior Member
 
Join Date: Aug 2011
Posts: 3
Rep Power: 0
axs is on a distinguished road
axs axs is offline
Junior Member
 
Join Date: Aug 2011
Posts: 3
Rep Power: 0
axs is on a distinguished road
Default Powering down a newwish greenie

Ok, so I got me a 5mW newwish laser (the one called "true green" on DX), it's really cool, the weight is right, the size is right — well, I like it. There's one problem though: it's too bright. I'm going to use it as, well, laser pointer on a white screen several meters from away, and right now the spot rather uncomfortable to look at.

So I want to power it down.

I disassembled it and tried to turning that resistor, but ended up increasing the power a bit — the current was ~280mA initially, now it's around ~350mA, and I can't get it back down for some reason. Ok, I have no reliable 3V source right now, I guess I'll try tuning it again once I'll get something to power it from without the need to hold the module, the probes and the batteries with only two hands.

Anyway, before I do that: does anyone know if it's possible to reduce power of these things? And how much? Maybe changing the resistors on the board etc?


axs is offline   Reply With Quote







LPF List of Laser Pointer Companies (link opens new window)







Old 08-26-2011, 05:58 PM #2
ARG's Avatar
ARG ARG is offline
Super Moderator
 
Join Date: Feb 2011
Location: Canada
Posts: 6,987
Rep Power: 1891
ARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond repute
ARG ARG is offline
Super Moderator
ARG's Avatar
 
Join Date: Feb 2011
Location: Canada
Posts: 6,987
Rep Power: 1891
ARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond reputeARG has a reputation beyond repute
Default Re: Powering down a newwish greenie

If you want it to be less powerful, try an IR filter, it would step down the power a bit. More if it's an inefficient light transfer.

Last edited by ARG; 08-26-2011 at 05:59 PM. Reason: Spelling
ARG is offline   Reply With Quote
Old 08-26-2011, 09:08 PM #3
axs axs is offline
Junior Member
 
Join Date: Aug 2011
Posts: 3
Rep Power: 0
axs is on a distinguished road
axs axs is offline
Junior Member
 
Join Date: Aug 2011
Posts: 3
Rep Power: 0
axs is on a distinguished road
Default Re: Powering down a newwish greenie

Ugh, correct me if I'm wrong but filtering out invisible IR shouldn't affect visual brightness of the beam. A piece of (visible-)colored not-exactly-green glass would be a better choice I guess.

My initial idea was to reduce diode current, I assume it's easier to do than altering laser's optical components.
axs is offline   Reply With Quote
Old 08-26-2011, 10:35 PM #4
Cyparagon's Avatar
Class 4 Laser
 
Join Date: Sep 2007
Location: Wisconsin
Posts: 9,141
Rep Power: 9321
Cyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond repute
Cyparagon Cyparagon is online now
Class 4 Laser
Cyparagon's Avatar
 
Join Date: Sep 2007
Location: Wisconsin
Posts: 9,141
Rep Power: 9321
Cyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond reputeCyparagon has a reputation beyond repute
Default Re: Powering down a newwish greenie

The pot (or "resistor" as you put it) doesn't work any more?
__________________
A problem well stated is a problem half solved.

Last edited by Cyparagon; 08-26-2011 at 10:35 PM.
Cyparagon is online now   Reply With Quote
Old 08-27-2011, 04:09 AM #5
InfinitusEquitas's Avatar
Class 4 Laser
 
Join Date: Mar 2011
Location: 20 Minutes from NYC.
Posts: 16,004
Rep Power: 9453
InfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond repute
Send a message via AIM to InfinitusEquitas Send a message via MSN to InfinitusEquitas Send a message via Yahoo to InfinitusEquitas
InfinitusEquitas InfinitusEquitas is offline
Class 4 Laser
InfinitusEquitas's Avatar
 
Join Date: Mar 2011
Location: 20 Minutes from NYC.
Posts: 16,004
Rep Power: 9453
InfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond reputeInfinitusEquitas has a reputation beyond repute
Send a message via AIM to InfinitusEquitas Send a message via MSN to InfinitusEquitas Send a message via Yahoo to InfinitusEquitas
Default Re: Powering down a newwish greenie

Use different batteries. I find nimh AAA's don't work nearly as well for my pens... but they do provide better run time.
InfinitusEquitas is offline   Reply With Quote
Old 08-27-2011, 06:17 PM #6
axs axs is offline
Junior Member
 
Join Date: Aug 2011
Posts: 3
Rep Power: 0
axs is on a distinguished road
axs axs is offline
Junior Member
 
Join Date: Aug 2011
Posts: 3
Rep Power: 0
axs is on a distinguished road
Default Re: Powering down a newwish greenie

Got a suitable 3V source today and did some testing.

Quote:
The pot (or "resistor" as you put it) doesn't work any more?
It does, I was wrong initially. Tried turning it carefully with the power on, and yes, the effect is clearly visible.
Maximum current I can get is ~420mA (leftmost (ccw) position), minimum current at which laser beam is still there is ~140mA; at ~130mA it cuts off (that's close to rightmost (cw) position). Currents around 160..180mA seem to give me the brightness I like.

Now there's another problem. The laser beam is quite unstable at those currents. I can set it to 160mA, turn it off, let it cool down, turn it on and get no beam at all. At higher settings, it will start with a faint beam and will slowly gain power in 10 seconds or so. Left it set to 200mA for now, looks like the laser at least turns on consistently at this setting.

Quote:
Use different batteries
Yeah, that was the first thing I tried. I didn't notice any change in brightness at all with NiMH instead of alkaline cells.
axs is offline   Reply With Quote
Old 08-28-2011, 05:46 PM #7
Bluefan's Avatar
Class 3R Laser
 
Join Date: Aug 2009
Location: The Netherlands
Posts: 1,482
Rep Power: 62
Bluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond repute
Bluefan Bluefan is offline
Class 3R Laser
Bluefan's Avatar
 
Join Date: Aug 2009
Location: The Netherlands
Posts: 1,482
Rep Power: 62
Bluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond repute
Default Re: Powering down a newwish greenie

With batteries the instabilities will only be worse. I'd go for a cheap ND filter, with some some luck this would also attenuate the IR. Turning down the pot won't lower the IR output accordingly. Adding an IR filter would be an idea anyway.
__________________
Highlights of my laser collection:
Big Sky Er:YAG - HP 8168D 1480-1570nm tunable laser source - Spectra Physics 3800 modelocked Nd:YAG - lots of IR diodes and bars - LPC-815 200mW 650nm - DL 6353TL 635nm 5mW - HP5501A stabilized HeNe - 2x Melles Griot 05-STP-910 stabilized HeNe - Spectra Physics 3500 Dye laser - REO 30536 543nm 2mW - Coherent DPY315-100 532nm 100mW SLM DPSS - Lexel 85 - 3x B&W tek 10mW 473nm - 445nm 3W Bluefan Sabre module - SF-AW210 150mW 405nm - DPSS inc 355nm 100mW Q-switched

Power meters:
Laser precision RkP-575 w/ RK-5710 - Ophir 10A-V2-SH - Ophir OEM 20C-A - HP 8152A w/ 2x 81521B - Coherent 212 - Anritsu ML93 w/ MA98A - 2x laser precision AM-400 - Leader LPM-8000

Bluefan is offline   Reply With Quote
Old 08-28-2011, 11:41 PM #8
Benm's Avatar
Class 4 Laser
 
Join Date: Aug 2007
Location: Netherlands
Posts: 7,428
Rep Power: 15904
Benm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond repute
Benm Benm is online now
Class 4 Laser
Benm's Avatar
 
Join Date: Aug 2007
Location: Netherlands
Posts: 7,428
Rep Power: 15904
Benm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond repute
Default Re: Powering down a newwish greenie

The instabilities cannot be overcome, i'm affraid. The problem is that you want to operate the laser at the point where in barely produces green light. The required current to do that is very dependent on temperature. This gives the problem that it does what you want when the laser is warm, but after you switch it off and let it cool down, it doesnt produce any green light, then starts to flicker until its warmed through.

The only way would be to rework the driver, either to use PWM to control the average brightness, or you need to include some sort of optical feedback that 'reads' the amount of green light produced.

The latter approach was used in an early generation of newwish pointers, but i have never seen it since.
Benm is online now   Reply With Quote
Reply





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On











Loading








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes






Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 01:26 AM.


Powered by: vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2017 Laser Pointer Forums, LLC