Showing Off My New DIY Red 20x Garrity

Hello everyone.

I have just completed my very own DIY burning laser. Im am pretty darn happy about it too so I wanted to share it with you all.

The laser diode is being driven by DDl's circuit.

The laser diode is an open can from a 20x lite-on dvd burner.

It is housed in a Garrity LED flashlight that has been completely gutted.

I am powering this laser with a 7.4 volt lipo pack from a Team Losi Micro T.

All in all this was pretty easy to build. The tough part was learning about everything.

Many thanks to amkdeath for all his help. Without his time and answers I would have never figured out what was wrong when it went wrong.

Here are some pictures for you all to view and a video at the end. I guess I cant post links but I did not know of any other way to get the video here.

















I think thats about every picture you would want to see of it.

But for now I am putting the laser away until I can afford safety goggles.
This thing makes your eyes hurt if you look anywhere near it for more than a minute or so.


youtube.com/watch?v=sGH57OZS3Iw

Nice job, you really went the extra mile. I'll bet your laser will last you a long time. Have you tested the output.

Thanks for the input.

No, I have not tested the output. I don't have a way to do so.
I would really love to know what it is. It lights matches and
pops balloons in seconds.

It took me a long frustrating time to come up with the parts and build this.
I certainly hope it lasts a long time.

It seems that the battery I am using does not last very long in this thing.

I just had a nice scare when my laser beam suddenly stop shining. I put another battery in it and it works. I thought for sure it had died this time.

I have had too many close calls with this thing. Im really shocked I havn't killed it yet.

Seeing how its my first try and I have never killed a diode and don't want this to be my first.

Be careful with those Li-Po's, they like to blow up if misused! If you really want to know power ouput, send it to SenKat(maybe not him since he just had surgery) or another member with a power meter, im sure if you pay postage they will test it for you free! Nice work!

I'd insulate that circuit. Maybe embed it in resin or something. Main thing is that tab from the LM317 is also Vout and if that touches something else including the body of the torch you could have negative consequences.

I have it completely sealed in electrical tape. I had to cut thin pieces and wrap it like a mummy kind of.

I know all about lipos. Most of my rc toys use them.

Hemlock Mike posted a comparison graph between the Sony diode and the open can. I will repost it, but you need to know how much current your laser is drawing. It looks like you have 2 10ohm resistors in parallel. The current would be 250ma's and the output would be ~125mw's.

You can easily power an open can with 350ma's, which will boost the output in excess of 200mw's. But you would need to make sure it doesn't get too hot. IMO the AMC7135 regulator is the perfect solution and you can use 3 Nimh batteries or 1 Li-Ion to power it. Anything over 4.5 volts and the regulator begins to get hot.

http://www.laserpointerforums.com/forums/YaBB.pl?num=1191898669

Hmm... So this thing can be more powerfull.....

I like it as it is. But had a blast building everything.

Is there an easy way I can run 350ma with the current driver?

That would be nice. What I really want is to be able to burn things from farther away.

If I had the AMC7135 then that would be great. My flashlight used to take 3 AAA batteries.
Now I have the battery pack and its a pain. It doesnt last all that long either.

Since I had so much fun learning and building this laser I think I might build another one at some point.
But I really need those laser goggles first.

You can simply add another 10 ohm resistor which will increase the current to 378ma's. To calculate for the resistor needed, you take the sense voltage and divide it by the current. The sense voltage is 1.25 volts.

Another way is to take the sense voltage and divide it my the resistor used.

I don't know the capacity and discharge ratings of your lipo, but you need to take this into consideration too.

I could be mistaken but from the picture of the raw output projection, it appears that the output may be occluded somewhat. It appears that the central portion of the beam is to the right (in the picture) of the exit aperture. Could this be caused by a slightly mis-aligned diode in the module? This would account for a significant loss of energy in the focused beam I think.

The picture shows the beam correctly, however I have looked at the diode and it appears to be nice and flush with the housing.

Also if I blow smoke through the beam I can see this as well. One side is solid red and the other isnt. Its hard to describe.

The lipo is a 7.4v 180 mah. I dont know the discharge rate. Im sure I can easily find out.

A 180ma battery will sag very fast and I bet the discharge capacity isn't all that great either. I noticed you edited your previous post and might be thinking about using the 7135. I am using it with my open can diode and a TEC, and have had it peak at 240mw's. BTW, I am running my TEC with a 7135 too. Granted I am using a Meredith module with a glass lens, but still if all you use is the 7135 with the setup you have, you will be putting out in excess of 200mw's.

I don't know if you have read any of my posts in previous threads, but I was running my open can with 600mw's for awhile before it suffered from COD. It was putting out 350mw's. It may have been I was really pushing the duty cycle. Even though I was using a TEC I am sure running it for long periods contributed to its death. Anyway, the point I am trying to make is I am certain your diode would last for a long time running with 350ma's. Just watch the heat.

I edited it to add the part about the smoke and the beam. or maybe you were talking about a different post.
Im going to purchase a digital multimeter some time. That way i will be sure of everything before i mess with the diode more.

Its my first baby I want to take good care of it. Thats why I learned how to build the driver to begin with.

Also I would like to use the 7135. Is that basically what the LM317T is? If all I have to do is go by one and swap them that would be nice.

Next I have to find a bluray diode.

DNM -- What is that square "window" in front of the focusing lens ??
Also, It looks like you have minimal heatsinking mass for the LD. If you jack the mA, Add more brass or something to the module.
But hey --- You did it. Welcome to the club !

Mike

That part you are looking at is actually a spur gear from an rc car. The square window is where the slipper sets in place. It was the only thing I had to use to fill it in. I just used a dremel to grind the teeth off the gear. The hole in the center was already a perfect size.

For heat sinking I wanted to get some washers with an inner diamiter that will fit snug around the housing. They would need to fit in the head off the flashlight and have even smaller washers in between spacing them out to create the fan part of the heatsink if you get what im saying.

--------- <-----Large washer.
----
---------
---- <----small washer.
---------
----
---------


Something like that. They would slide right over the module.