Ideas re: radioshack greenie

[AisuShiden]

So here in my hand is a radioshack greenie, that I have messed with.

First I tried the pot mod, but I did not want to cut a hole in the side of the pen, so I turned the potentiometer to the right some and tried the laser out. It didn't seem to get any brighter, maybe a tiny bit. I only once adjusted it with the laser beam on, and it didn't seem to get much brighter, if at all.

I then attempted to turn the pot counter-clockwise, until I felt no resistance. I turned it, and put it back together, but still no real difference in the brightness.

So I decided to cut the wires going to the photodiode. In another post I read, this made the laser considerably brighter. It actually seemed to harm the performance of mine, or change it very little. It flickered a bit, seeming unstable.

At this point it was time for a different approach. I soldered the wires back together. Then, using a small screwdriver, I applied a small piece of painters tape to the surface of the photodiode. The laser seemed to be a little brighter. I tested a piece of tape, and the laser easily shone through it. So I applied another layer to the photodiode. The laser seemed to be a bit brighter again. A third piece of tape made a small difference. The laser didn't shine much through three, so I stopped there.

Now, the laser dot on the wall seems brighter, but it also has more of a splatter of light around the dot itself. Could this be from the laser light reflecting off of the painters tape on the photodiode? I also feel like the beam was more visible last night, but that is a very subjective observation.

Now for the questions! ^_^'

Am I perceiving the laser as brighter because of the light splatter? Is my idea about covering the photodiode a realistic way to marginally increase the power of the light?
How can I measure its power, with a digital multimeter? Why did the pot mod not work, did I do it wrong?

Thanks in advance, writing this has been quite arduous, since my kitten has been biting and attacking my hands/keyboard nearly the entire time. -_-'

 

[AisuShiden]

Anyone? Tonight is an amazing meteor shower and I would like to take my laser... I'm a perfectionist though and its going to drive me crazy unless I know it is as bright as possible.

 

[mattmagic100]

Its honestly not even a good idea to pot mod your laser because it will ruin the lasers life. you will need to change the battery constantly. and itll most likely just die if you pot mod it to much.

 

[The_LED_Museum]

...How can I measure its power, with a digital multimeter?...

If you have a solar cell lying around, you can indeed measure laser power with an ordinary, "garden variety" DMM.

Connect the solar cell to the DMM, set your DMM to a low mA scale, irradiate the solar cell with the laser, note the meter reading (wave the laser spot around the surface of the cell so the meter reads its highest), and apply the following mathematical formula:

(current in amps as shown on meter)*1239.7/532/0.97

The resulting value will be your laser's power output in milliwatts (mW).

The "532" here is the laser's wavelength in nanometers; replace it with your laser's wavelength as necessary - "405" for Blu-ray lasers, "645" for typical red diode lasers, etc.

 

[AisuShiden]

If you have a solar cell lying around, you can indeed measure laser power with an ordinary, "garden variety" DMM.

Connect the solar cell to the DMM, set your DMM to a low mA scale, irradiate the solar cell with the laser, note the meter reading (wave the laser spot around the surface of the cell so the meter reads its highest), and apply the following mathematical formula:

(current in amps as shown on meter)*1239.7/532/0.97

The resulting value will be your laser's power output in milliwatts (mW).

The "532" here is the laser's wavelength in nanometers; replace it with your laser's wavelength as necessary - "405" for Blu-ray lasers, "645" for typical red diode lasers, etc.

Mine is a 532 which i think has an 808nm pump? I left the ir filter intact, so this method would only measure my output of green? (that is what I want, to measure green)

I tested it against a non-modded radioshack green,both on brand new alkalines as a control measure. Mine is much brighter! I have a picture of the two dots next to each other which I will post once I am not using a cell phone to post.. So the mods worked, I am quite sure that it did get brighter the more layers of tape I applied to the photodiode.

Thank you for this method, it seems more accurate than the other methods I have seen (like placing the DMM in between the negative battery terminal and the battery, and measuring the mA that goes through the DMM).