Newbie Questions - is it this easy?

Note: I've edited this post at least a dozen times. I have not gotten any feedback yet, but I think I'm learning from constantly reading on the Internet.


OK...let me see if I understand this...

I start with a laser diode, which is about 12mm in diameter.
http://www.ebay.com/itm/5mW-532nm-3...144?pt=LH_DefaultDomain_0&hash=item3cc93085c0

It has the driver board built-in.

It has the collimating lens built-in. (I was confused over that for quite a while.) The lens sits inside the brass-looking-thing. The lens has male threads on it. The purpose of a collimating lens is to get the light going in the same direction. https://en.wikipedia.org/wiki/Collimator

If I want to, I can put it inside a heat sink. (A 5mw laser probably will not need a heat-sink.)
http://www.ebay.com/itm/Heatsink-fo...786?pt=LH_DefaultDomain_0&hash=item3a6de101da

I think I use "Arctic Alumina Thermal Adhesive" to attach the diode into the heat sink.

The driver needs 3.7V to 4.2V, so I can run it off a lithium battery:
http://www.ebay.com/sch/i.html?_from=R40&_nkw=18650

Other versions take 3.0 volts, so I should run them off x2 AAs or a single 3.0V lithium battery.

Thanks in advance!

P.S. I posted links to people selling things. I'm not advertizing anything. I don't know these people or many money with them I just posted the links for clarification of what I'm talking about.

I have figured out that you can not just build up a solder nub on the + terminal of the laser diode module so it touches the heat sink. That shorts the + of your battery into the case of the diode housing, which prevents the light from coming on.

That's why everyone uses thermal epoxy that acts as an electrical insulator, then runs a wire between the + terminal and the body of the light. (I know that the body is - in flashlights, but in lasers that use the diode I got, the spring at the front of the flashlight is -, and the body is +.)

Thanks! I have a module in the mail. I figured on using an old flashlight enclosure but wonder if there are there standard enclosure for assembly?

How is your project going? You might consider googling for a forums that focuses on laser pointers. A laser pointer forums, if you will.

bshanahan14rulz said:

How is your project going?

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The school year has started, and I'm back to teaching college, so I have little time for lasers.

Before that, I was stuck trying to find a way to reliably solder a wire inside the tube of a flashlight.

Hmm, most flashlights are made of aluminum and will require a very special type of flux to solder to it. Is there a brass pill that you might could use to solder to instead?

I have a green module build, and on mine, I just used the brass 12mm case of the module. I don't know how to identify it, but I was told that the driver on my particular module was on the - side, so shorting the case to + was alright for my build. You might consider taking a multimeter and seeing if the + lead and the brass case of your module are continuous. If they are, then you can go back to your original plan of just using the brass case touching the flashlight body or heatsink as the + connection.

Did you choose a particular flashlight, or just a random one you had lying around?

bshanahan14rulz said:

Hmm, most flashlights are made of aluminum and will require a very special type of flux to solder to it. Is there a brass pill that you might could use to solder to instead?

Click to expand...

I have one spring connection that touches the forward end of the battery. I need to connect to the back end of the battery. The flashlight's case conducts electricity from the back end of the battery to the driver board. The problem is that my driver board needs to connect to the case.

What brass pill are you talking about?

bshanahan14rulz said:

I have a green module build, and on mine, I just used the brass 12mm case of the module. I don't know how to identify it, but I was told that the driver on my particular module was on the - side, so shorting the case to + was alright for my build. You might consider taking a multimeter and seeing if the + lead and the brass case of your module are continuous. If they are, then you can go back to your original plan of just using the brass case touching the flashlight body or heatsink as the + connection.

Click to expand...

If I short either lead (input to the driver board) to the brass case, the laser stops working.

bshanahan14rulz said:

Did you choose a particular flashlight, or just a random one you had lying around?

Click to expand...

I want to use a WF-502B for my laser. The diode takes up enough room that it only takes x1 123A battery.

brass pill - some lights have a brass pill that holds the driver and LED, and screws into the body. This way, people don't have to solder stuff while it is in a tiny tube. Drop-in lights have pills that don't screw into the host, but rather just drop into a pocket in the host.

Interesting module, isolated inputs and outputs on the driver. Mine was a 3.0V module, I had to mod it with a diode to keep it from overheating when using it with 3.7v nom.

I had a heatsink custom turned by a machinist for my L2, and as you can see here, I had to get creative to be able to keep the ability to use an 18650:

Also, radiant electronics sells a heatsink for WF-501B, and the store owner actually is friends with the machinist that made those. You might could shoot them an email and see if that heatsink will work for the 502b too.

As far as the + connection goes, as long as you isolate the module case from the flashlight body, then you should be able to use the heatsink as a connecting point, since the heatsink should have a good connection to the body. If you are getting the heatsink custom made, be sure to ask for a "grounding screw" sort of feature, this would greatly simplify what you want to do, all you'd do then is wrap the wire around the screw and screw it tight into the heatsink. The heatsink snug-ly touching the flashlight body would end up being enough for electrical contact.