From nothing to Laser - What's needed?

[shintashi]

my order for the LM317 and the Potentiometer came in, so now I have a bunch of LM317s and two huge pots. I also went to the hardware store and picked up a metal tool case for all this equipment, because it was overflowing. I was told I could have used a plastic tool box but the box might be damaged by a hot soldering station if I wasn't careful, so I went with a metal one. I noticed the soldering station is kind of big, so a larger toolbox was necessary - and will probably be necessary for anyone with a soldering station, instead of a regular soldering iron. While I still have plenty of space for more stuff, I'm also aware I still have more stuff to buy, like the laserbee, hosts, heat sinks, batteries, etc.

Tool boxes range wildly from $8 for plastic to $30 for metal.Either way I'm probably going to have to get one of those little sorting boxes from a craft or fishing shop to hold all these diodes, resistors, capacitors, etc, and suggest anyone starting from scratch is probably going to spend some money on multiple containers, unless you have some retired person's pill organizer.

I found I could use my multimeter to test temperature and got my target up to 741 degrees F in the first 20 seconds. The multimeter says it can go up to 1400 F, so it would be interesting to see how hot burning lasers actually get, because that would also tell me what kinds of soft metals they can melt. For example:

Useful Melt Points
63/37 solder: 361 F
60/40 solder: 370 F
tin: 449 F
lead: 621 F
zinc: 787 F
magnesium: 1202 F
aluminum: 1220 F

I also got a vice grip, but I probably need some additional clamping devices to attach it to my metal table, since I don't have a wooden work bench. If you want a work bench to attach your vice to, you are looking at between $80 and $700, with $200+ being normal. Again, this isn't necessary for someone who already has everything, but in this thread, we are talking about an essentially empty apartment and a full bank account.

This makes 6 trips to the electronics store, two internet orders, 1 trip to the hardware store, two trips to book stores, and 19 days in, but the Laser still eludes me.

 

[Bionic-Badger]

Sorry about the late response; I was at Burning Man.

Vice grips are okay, but I'd get an actual vice, so that the diode press isn't pushing in at an angle.

The place I get electrical parts is from Mouser. Don't be intimidated by all the parts they carry. Just set up an account and add the parts you think you'll want some day into "projects." I often do that as I'm looking for stuff I might want in the future. Then when I really want to order something, I'll buy a bunch of the parts I'll know I'll use some other day. Some parts, like Schottky diodes I've bought a thousand of because it was pretty cheap (like $10 if I recall) in such quantities. I'll never need more again.

Stuff like resistors are nice to get in large quantities. I've bought assloads of 1% tolerance 1kohm resistors among others. If you can get to a reasonable quantity price break, it is often worth it to just buy more of what you need in case things break.

For your pots, try to buy multi-turn pots so that you have more precision. They're relatively expensive, but you can always reuse them elsewhere if things don't go right. Also pay attention to the shape and casing of the parts you buy. If you're getting something like a LM317, it is usually nice to get the ones that are in a TO-220 form factor because they have a larger heat sink and can be screwed onto something else. SMD/SMT parts are surface mount parts, and should be avoided unless you know what you're doing and have the proper equipment to deal with them.

Another good source of parts if you don't need tons of them is Sparkfun. They're more of an electronics hobbiest site, and have some nice stuff to work with if you desire. Get some wire, shrink wrap, etc. and you'll be making some nice projects. They also have things like breadboard and resistor kits and such if you want to have a decent selection of parts just to experiment with.

 

[shintashi]

Sorry about mislabeling tools. My vice is one of those metal block things that looks like this:

Table Vice

I'm still learning about electrical components, and I got three new pots today; a 1k, a 5k, and a 10k. I couldn't get the LED to dim all the way off, but the dim/bright range was much higher. I didn't notice much difference between the 5k and 10k. I picked up some capacitors ranging from 470 to 10,000MF, but I need to do more reading before messing with them. I've got some rechargeable 123 batteries and one 18650 from the Fry's, but I'm saving them for my first build.

My Red and 405nm diodes came in from England, and I picked up some 445nm diodes over the weekend, as well as some focusing lenses. I just realized I still need a TON more parts,

including:

hosts
heat sinks
modules (I still dont know what these are, but I think the lens and/or diode goes inside)

and I'm still trying to figure out how to build the driver. The pots I have are bigger than the drivers I've seen, but I also so tiny pots the size of buttons.

At this point I'm not sure why the parts of a driver are so weak, or what half of them do.

This makes about 8 trips to the electronics store, two internet orders, 1 trip to the hardware store, three trips to book stores, a field trip across the state, and after 33 days, my custom laser is still but a dream.

 

[Bionic-Badger]

You don't need a tiny pot for a labby build. One of those multi-turn breadboard pots work great. I'd start making a labby laser before moving onto a portable one, which usually requires more complicated drivers and is a pain in the ass to fit in. With the labby you can build the laser on a table using the DDL driver which is pretty easy to build. Once you have that done, you can measure the performance and use that experience for future lasers.

 

[shintashi]

You don't need a tiny pot for a labby build. One of those multi-turn breadboard pots work great. I'd start making a labby laser before moving onto a portable one, which usually requires more complicated drivers and is a pain in the ass to fit in. With the labby you can build the laser on a table using the DDL driver which is pretty easy to build. Once you have that done, you can measure the performance and use that experience for future lasers.

I've got some red diodes to mess around specifically to build a lab laser before I try making a hand held, so I agree. Today i'm going to be messing with my bigger capacitors to see what they do with an LED, since the 47mF didn't appear to do anything.

I still need to get heat sinks and some way of fine tuning the position of the lens. I thought of just wrapping the lens in wire coiled into a spring and then sliding it slowly, but that seems like a bad idea for some reason. If there's more parts I need to make this work, I'd love to know what they are.

 

[Bionic-Badger]

You really don't need capacitors in your design, and often they result in burned out diodes if you don't remember to keep them shorted when you solder them up. Use capacitors if you want to clean up a signal. Don't use them if the devices you're already using clean up the signal for you (e.g. an LM317).

For your lenses and such, get an Aixiz module as a start. They're made for holding your laser diode and the lens. Another one you can get is the larger 18mm module holders from O-like. They come with a nice glass lens for red (there is another one for blue to you can buy), are well heatsinked, and don't even need you to use a press to hold the diode in place. It might be a nice start.

 

[shintashi]

You really don't need capacitors in your design, and often they result in burned out diodes if you don't remember to keep them shorted when you solder them up. Use capacitors if you want to clean up a signal. Don't use them if the devices you're already using clean up the signal for you (e.g. an LM317).

For your lenses and such, get an Aixiz module as a start. They're made for holding your laser diode and the lens. Another one you can get is the larger 18mm module holders from O-like. They come with a nice glass lens for red (there is another one for blue to you can buy), are well heatsinked, and don't even need you to use a press to hold the diode in place. It might be a nice start.

Excellent!

I'll order some of those tonight!

edit: ordered 2 for reds and one for blue/violet to mess around with once I get the hang of it.

When pressing in a diode, I presume it's the lens that isn't in fixed position. Olike has rectangle drivers, and some people have these round drivers. I'm hoping to learn enough to make my own driver small enough to fit inside my host correctly.

I got around to playing with the capacitors and burnt out a 17 candella green LED in about 4 seconds, but I'm not sure why a weaker 3 candella Red diode is still trucking. I discovered the bigger the capacitor, the longer the fade out, but also, the longer the initial fade out, exponentially the longer the dim glow. I found this could be stopped immediately by connecting the two wires of the capacitor. While the initial dimming with a 10,000 muF cap only took about a second or two, the dim glow took several seconds to wear off. It also took practically zero seconds to charge up the capacitor. I'm still not sure what this all means, but I've now messed with

batteries
LEDs
Potentiometers
capacitors
1 way diodes/rectifiers

I still don't know what the LM317 does and I notice some stuff seems to have more than one wire sticking out of it. I'm going ot look around LPF for more on these weirder circuits.

 

[shintashi]

I got some switches, 9volt battery clips, and larger resistors from the Radio Shack, and found out while soldering a Cree LED to a switch mechanism that soldering sometimes produces this smoky crap that smells awful, and generally shouldn't be inhaled. Normally this would be a no-brainer but working with tiny electronics and precision also requires me to get a whole lot closer than I wanted to for a longer time than I can really hold my breath, so I ended up buying an air filter as part of my soldering kit. Also realized I had to get an extension cord for the soldering Iron because the cord is stupidly short - like 3ft or so. I'm not sure what temperature I'm supposed to be melting this stuff at by my soldering tip is stupidly small and the surfaces are taking an eternity to heat up, probably because they are super thin round roped wire and my contact surface is needle-like. I've had to "pool" my solder instead - once a molten dot is created, solder melts quickly into the pool. It's very different from Arc Welding.

I finally ordered some safety glasses from OEM Laser, although my modules from O-like haven't arrived yet. That's kind of odd actually -
OEM
O-Like
Odic Force

What's with all the "O's" in laser products?


This makes about 10 trips to the electronics store, four internet orders, 2 trips to the hardware store, three trips to book stores, a field trip across the state, 43 days, and still no custom laser...

 

[shintashi]

So my 3 modules came in, and to be honest, I'm not really sure what to do with them. They Screw apart and appear black with fin like things - like the front of the vaisho laser pointers, which I'm going to assume is to cool them down. Inside is a tiny hole, a spring, and something that looks like a lens tightly wrapped in some kind of paper. I realize at this time I still need hosts, but I had the opportunity to learn more about electricity from someone and practiced some soldering. They suggested I get a variable power supply from Ebay and attach it to a 12V power supply. In the mean time I made a flashlight that burned out in about 4-10 seconds of continuous use. Buying hosts is super hard in person - you either have to buy a new flashlight or find something vaguely similar in shape. I tried sprinklers from a hardware store and eventually went with a coin case, and drilled out a hole for my light and switch. Even working with a soft plastic turned out to be less than precise and my need for a working mill and solid table clamp became blazingly apparent.

 

[shintashi]

so my laser protective goggles finally came in from OEM. They are shiny red and definitely require contact lenses instead of glasses. They turn everything red but protect from about 80nm to well over 532nm, meaning they work for violet, blue, and green lasers.

I've deconstructed a broken flashlight experiment and salvaged a switch and two 9 volt clips but the cree LED is dead (I have lots more). I managed to solder together my Red flash light after finding a battery holder for the A23 12v and used a razor to trim the edges so it would fit in the host. Also had to re-bore the led hole to prevent it the lens cap from sticking to my led and then twisting off my connections. This is probably similar to what Yobresal was talking about when he warned against twisting off the top part of the host, because it would destroy the driver connections. I've come to conclude I need some kind of non conducting substance I can wrap around my wires, but I'm not sure if electrical tape is the best bet, because the wires are so tiny the tape becomes cumbersome and unravels. It's almost like I need some kind of quick dry putty or liquid rubber.


55 days, and I'm a few steps closer to understanding how to set up a laser, but I'm a bit concerned about stabilizing current vs. stabilizing voltage. It's clear my little cree led was overheating rapidly while the voltage probably stayed the same. If I'm not mistaken, I want my regulator to control the amperage?

 

[shintashi]

so today I made my second attempt at creating a ~125mW laser. Unlike last time, I didn't accidentally clip the wrong connecting wire on my diode (yay dyslexia). I got all my soldering pretty much correct, hooked up an LM317 to a pot set to about 4.9 ohms, and then tried pressing the diode. No go. The Olike module is downright arcane in its lack of instructions, but I basically figured out I could press the diode into the brassy looking fitter doodad that then screws into the back of the heat sink where the lens rests. I wouldn't be surprised if I cracked the diode during this process, and probably exposed it to static on another occasion, since "hermetically sealed static free zone" wasn't added yet to my "list of things you actually need to make a laser".

Here's another part no one mentioned: if your diode has a larger diameter than will fit in your module, what do you do? You have to drill out the module. But how do you know what diameter do you need? I mean 1.2mm and 1.144 mm look about the same to my eyes, so I realized I needed a micrometer and some other kind of gauge for measuring those tiny holes. I also noticed the drill bits most people have don't come in many ranges at the diameter of a diode.

Any way, while following the instructions of some random video, I realized too late that the circuit parts I had weren't going to fit inside my module so I ended up clipping one of my wires and attaching an on/off switch. The video said I needed about 3V more than whatever was listed for the diode, I seem to recall some fuzzy math about 4.3V was listed, and after my A123 didn't do anything, I tried an 18650 and Fiat Lux.

But that was about the end of the highlights. I noticed the lenses only provided me with a range of about 1 inch before it blurred away. I tried using an Aixiz lens, which was more clear, but it still blurred away after a similar range. By this time, I realized I had probably made ten or twenty mistakes along the way, but figured I might as well go for broke and adjust the Potentiometer that was substituting for the '4.9 ohms" of resistors I didn't have. (had two 1ohms and a bunch of 20 ohms, but the closest thing to 4.9 ohms was a 25 ohm pot tuned with a multimeter). Messing with the pot produced visible results, in terms of brightness, and I'm guessing I hit some kind of magical threshold because there was a point where it was considerably brighter than before. The focal range in all cases was still about an inch.

I learned a lot this time, about the probable way in which the modules are put together, and how a diode might fit in them, though I could be completely incorrect.

I also learned one of the most useful tools no one ever mentions (or likely uses) is a white ink pen, which is great for noting things like polarity on black metallic surfaces.

Perhaps someone in LPF knows what happened to my diode, and whether I did in fact screw it up, which is what I'm guessing happened. I think the most useful thing a newbie could have is someone close by who knows what they are doing. :bowdown:

 

[Ablaze]

Well I just stumbled on this thread and it's an interesting read.

Some quick soldering tips: For soldering pens with those needle tips the tip is not the hottest part. To melt things you typically have to use the flat part (of the < shape).

For your wire isolation problem: There is something that is made just for that. It's called shrink tubing (or heat shrink). If I get it online I typically get it from here. For small quantities, however, you can find it at pretty much any store that sells solder. "Double wall" means it has glue on the inside that makes for an excellent seal, but any shrink tubing is probably sufficient for your application.

 

[Kevlar]

Your focusing problem sounds like you might have the lens in backwards.

 

[RedHazzard]

Some very useful things to avoid shorting out your laser is electrical tape/liquid electrical tape and heat-shrink tubing.

 

[shintashi]

While I'm sure I messed up my diode and my power supply is probably insufficient, the proximity and orientation of the lens was definitely the primary candidate to going from being a fancy lightbulb to a crappy laser.

Not only was the lens in backwards, but it was physically impossible to get it close enough in the module to the diode to make a difference, so I took out the diode and fiddled a bit with different lenses and discovered with an aixiz lens, I can put the lens very close to the diode. Unfortunately, the lens still has to go about a full millimeter beyond the flush so I had to use a screwdriver to continue inserting the lens. These photos are the approximate result so far. I would not be surprised if the laser is only about 1-3mW.

Images:

my "dot" at a few feet looks like rippling waves about 2-3 inches wide. I'm assuming that's either lens or diode damage. I think my next project will be a load tester thingamabob, and I want to experiment with using multiple resistors to lower resistance, because I spaced it yesterday.

 

[notahardwareguy]

To add my 2 cents:

- did not see anyone list heat shrink tubing (great for covering your connections)

- hobby board

I built a hobby board before starting my laser build. It is a .5 inch X 30 inch X 30 inch board with a raised molding edge all around (like a picture frame) and rubber feet. When I am working in the house, all of my stuff is on this. Saves the table tops and prevents the wife from having something else to fuss about. I think I spent like $15 on the parts to build it and about 20 minutes to put together. The molding edge keeps stuff from rolling off and getting lost.