Science Project

[Dr Duff]

​

I need to complete a Science fair project. Quite simply, I have purchased three lasers pointers, two of which seem to be the same model. Although, the nature of my project requires me to modify these lasers so that I may burn items with them. I know that "pot" mods may reduce the life of the diode, yet that is quite redundant seeing that I only would need the lasers to function for an approximate minute. Although as I will mention below, I would discover that my laser pointers (or at least the two similar pointers) do not have a potentiometer, yet I mean to state that I am open to options that may slightly lessen the laser pointers life. I have seen videos of soldering components to achieve a greater wattage, yet obviously the circuitry in my laser pointers will be labeled and configured differently from the models in the video. I have purchased all of the laser pointers from "Amazon.com", and will provide the URL's below. That being said, merely "googling" the Item Model Number and ASIN given on the technical details won't bring anything useful up.

Amazon.com: American Science & Surplus Red Laser Pointer With Case and Batteries: Electronics

Amazon.com: 5mw 532nm Astronomy Powerful Green Laser Pointer - Black: Electronics

Amazon.com: 5mw High Quality Violet Purple Blue Ray Laser Pointer Pen: Electronics

​

I understand that these are extraordinarily cheap laser pointers. I understand that it is ridiculous to attempt to modify these to dramatically destructive power. I only hoped to push the power enough to scorch some egg whites.

​

I had spent probably what had been too much time trying to figure out how to disassemble one in the first place. Videos would spend 5 minutes describing how to get the tip of the pointer off (which I had figured out myself anyway) and then seemed to completely ignore the procedure for removing all the innards. I eventually (and begrudgingly) took a powered precision hand saw and ran it up the case, which is where I have peeled it and took out the diode. So, this circuit dose not have a potentiometer, which may have made this just so much easier, and I am unsure of what components to touch.

So how can I modify these?

 

[lasersbee]

I need to complete a Science fair project. Quite simply, I have purchased three lasers pointers, two of which seem to be the same model. Although, the nature of my project requires me to modify these lasers so that I may burn items with them. I know that "pot" mods may reduce the life of the diode, yet that is quite redundant seeing that I only would need the lasers to function for an approximate minute. Although as I will mention below, I would discover that my laser pointers (or at least the two similar pointers) do not have a potentiometer, yet I mean to state that I am open to options that may slightly lessen the laser pointers life. I have seen videos of soldering components to achieve a greater wattage, yet obviously the circuitry in my laser pointers will be labeled and configured differently from the models in the video. I have purchased all of the laser pointers from "Amazon.com", and will provide the URL's below. That being said, merely "googling" the Item Model Number and ASIN given on the technical details won't bring anything useful up.

Amazon.com: American Science & Surplus Red Laser Pointer With Case and Batteries: Electronics

Amazon.com: 5mw 532nm Astronomy Powerful Green Laser Pointer - Black: Electronics

Amazon.com: 5mw High Quality Violet Purple Blue Ray Laser Pointer Pen: Electronics
I understand that these are extraordinarily cheap laser pointers. I understand that it is ridiculous to attempt to modify these to dramatically destructive power. I only hoped to push the power enough to scorch some egg whites.I had spent probably what had been too much time trying to figure out how to disassemble one in the first place. Videos would spend 5 minutes describing how to get the tip of the pointer off (which I had figured out myself anyway) and then seemed to completely ignore the procedure for removing all the innards. I eventually (and begrudgingly) took a powered precision hand saw and ran it up the case, which is where I have peeled it and took out the diode. So, this circuit dose not have a potentiometer, which may have made this just so much easier, and I am unsure of what components to touch.

So how can I modify these?

You are not going to do too much burning with those 5mW Lasers...
You are wasting your time and efforts with those 5mW Lasers...

Buy a proper high powered Laser to do your experiments and
get some appropriate Laser Safety Goggles/Glasses...


Jerry

 

[ZRaffleticket]

Not that I recommend doing this but the IR diodes in the greenies may be capable of burning some thin plastic.
Though, safety goggles are a must cause invisible light is pretty dangerous.

 

[Tech_Junkie]

On top of what has been said, white doesnt interact well with green. You'll want violet lasers well over 100mW to get any time of reaction. Even then the majority of cheaper (under $1000) lasers need to have the power focused to a small point to burn well. So you will not be burning a big enough area to see a good result. You'll end up with small white flecks if your lucky. More than likely you'll get small black spots, because it will burn the egg white.

I dont try to put downs anyone's projects. But in this case you may want to rethink this project.

 

[Dr Duff]

As I have stated above, I firmly understand how feeble these lasers are. How 5 mw lasers are. Although, I am a not a person of particular personal wealth, and lasers are a particularly expensive commodity (especially since I require three). I already have these laser pointers and hope I can push them to make some mark on something. I don't necessarily need a conflagration machine. I thought that egg whites wouldn't work due to the albedo, although my instructor pushed it on me because she said that egg whites are similar in fragility to the flesh of the eyes. If egg whites aren't going to be as susceptible to laser beams as my instructor thought, than I think its aright to go ahead and just substitute a black object. Would any object in particular be best to use, or just something black? Also, please do offer steps I can take to make to modify these lasers. I don't sound irrational, if I do. I just have an expectation to meet (that is to merely to have visually mark a medium to compare three laser wavelengths)

 

[benmwv]

Are you planning to burn cooked or uncooked egg whites? Uncooked definitely won't work, and even cooked won't work with these lasers. You would really want a 405nm like tj said. I don't think you could burn uncooked eggwhites without a focusable laser over maybe 500mw, and even then it would be a challenge.

Also, if you are trying to demonstrate laser damage to an eye you shouldn't use eggwhites. If you get hit in the eye it doesn't burn the white or clear part of your eye, it burns the fleshy parts inside. I would suggest using a piece of raw meat, like some cheap cuts of beef. Green is a good color for power absorption in flesh, but those lasers aren't going to do any good.

That said, if you want to increase current I would suggest either building a new driver with an lm317 or maybe soldering another 1 ohm resistor in parallel with the part marked 1R0 on the existing driver. From a quick look, I think that will probably double the current.

Edit: oh also it looks like you have removed the crystals, so you no longer have a green laser you have an 808nm IR laser. DO NOT look into the little red light! It is much more powerful than it looks. I'm sure it's around 100-150mw.

 

[Dr Duff]

Well...like I had said in the post right above yours, I am alright with exchanging the eggs with something else. Yet, I am very grateful for the instructions. To be safe, would this work?

1K Ohm 1/4-Watt Carbon Film Resistor (5-Pack) - RadioShack.com

Also, when you say parallel to the above mentioned component (1R0) how exactly do you mean? In relation to my picture provided, adjacent below, adjacent left, adjacent right, above atop the underling metal? Forgive me if I am showing a high degree of being knowledgeable, I really would like to get all the facts and steps right.

 

[benmwv]

Well, I would really recommend building a whole new driver.

If you wanted to try and modify your existing one for more current though, my guess would be changing the 1 ohm resistor.

1k resistors won't do anything. If you want to be safe try maybe a 5 ohm. Parallel doesn't have anything to do with the physical position. Just solder the one lead of the resistor to one side of the one ohm resistor and the other side to the other side:
---/\/\/\---
---/\/\/\---
Solder the left sides together and the right sides together.

But again I recommend you build a new driver with an lm317. And have you tried out the laser since you took it apart? I'm pretty sure it's broken

 

[Dr Duff]

If I were to build three new drivers, would It be expensive? How much? Would they still fit in my cases? Also, trying to look on radio shack or for some nearby store, they don't seem to offer an exact 5 ohm resistor for some strange bizarre reason.

 

[benmwv]

Drivers wouldn't be expensive. You could make one with a lm317, 2 10 ohm resistors and a 100 ohm pot. All of this should be at radioshack. They won't fit in the cases and they will use a 9v battery, but they will be adjustable and much simpler than trying to mod the original driver. Plus it will look better for a science experiment to have your diy circuit powering it.

You should only need 2 drivers because you aren't going to get any green out of that one now that the crystals have been removed.

 

[Dr Duff]

Quick word on that. The crystal came unglued, yet it still emitted its red light (which is inferred. Which is dangerous. Which I know). Just repositioning the crystal over the same spot was easy and made a green light again, and I could just go from inferred to positioned crystal several times-no problem. I had set it aside with all the other minor disassembled parts when I cut the case open to retrieve the board and diode. Even after I cut the case and disassembled the the rest of the parts, I put it back together quickly to see if it all still worked. Which it did, green light and all. Then I put all those pieces aside to due more research and eventually post here. Only recently, the red light doesn't even show and repositioning the crystal doesn't present activity now either. If it worked before with the crystal out, why is the inferred not even working now?

Also, I want to know how expensive for the drivers. I say once again, I am not a wealthy person, and others (especially here) have a very different spectrum of what cheap and expensive is. But please, do make sure to provide comments on the former paragraph.

 

[lasersbee]

Quick word on that. The crystal came unglued, yet it still emitted its red light (which is inferred. Which is dangerous. Which I know). Just repositioning the crystal over the same spot was easy and made a green light again, and I could just go from inferred to positioned crystal several times-no problem. I had set it aside with all the other minor disassembled parts when I cut the case open to retrieve the board and diode. Even after I cut the case and disassembled the the rest of the parts, I put it back together quickly to see if it all still worked. Which it did, green light and all. Then I put all those pieces aside to due more research and eventually post here. Only recently, the red light doesn't even show and repositioning the crystal doesn't present activity now either. If it worked before with the crystal out, why is the inferred not even working now?

Also, I want to know how expensive for the drivers. I say once again, I am not a wealthy person, and others (especially here) have a very different spectrum of what cheap and expensive is. But please, do make sure to provide comments on the former paragraph.

Took me a couple of read throughs to figure out that you were
not inferring anything but meant to say InfraRed...

If your batteries are fully charged or fresh then you may have
damage your 808nm pump diode.

Read the info on this thread then find the parts on DigiKey to
give you an idea of the price on the parts...

http://laserpointerforums.com/f42/diy-homemade-laser-diode-driver-26339.html

Just the parts will be less than $5.00


Jerry

 

[Dr Duff]

Please forgive my error. I do try to be as orthographic as possible. Anyways, today I have gone out and purchased two lm317 components (I need three, yet they only had two. I will need to come back later or try somewhere else), ten 10 ohm resistors (because they just come in 5 packs) and a board of this type

Dual Mini Board with 213 Holes - RadioShack.com

I was actually wondering if the board I had purchased is suitable enough to build the driver. I currently possess a single 9v battery, yet I can acquire more. I still need to find three 100 ohm potentiometers because I was unable to find them in the selection at radio shack. I will have to try elsewhere. Besides what I have listed, what else might I need to make a test setup of one driver?

 

[benmwv]

You can make a bare-bones driver with just what you have now. It is recommended to have the cap, diode, pot and everything like in the thread Jerry linked but the most basic form can be made with just an lm317 and a resistor.

The + side of the battery connects to the "Vin" pin of the lm317. (with the metal tab facing down, the pin on the right)
One side of the resistor connects to the "Adj" pin (left) and the other side connects to the "Vout" pin (middle).
The + of the laser diode connects to the "Adj" pin.
The - of the diode goes to the - of the battery.
If the resistor is 10 ohms the current will be 125ma, if the resistor is 5 ohms (two 10 ohms in parallel) it will be 250ma.
I=1.25/R