My first kit, I have some Q

[ajengen]

Hello everyone!

I've lurked for a little while, and have been enamored by all the great looking lasers that I've seen here, and decided to buy my first kit. Being the noob that I am , I probably picked the wrong kit for a beginner, but I think I can put it all together with everyones help!

I bought a kit from seller crystallabs on ebay, and it is a really nice kit including a module/heatsink, driver kit (with 4 power output options), 405nm 250mw diode, some grounding straps and finger cots. The kit seems complete and I think any hobbyist would be happy with all the stuff you get.

My first question is about the capacitor that is included, I haven't ever used one this small so I don't know which side is the cathode/anode. My second would be about removing the extra connections from the laser diode, it won't fit in the module. How much heat can the diode withstand when desoldering?

Thanks a lot everyone!

 

[Morgan]

Okay, first, welcome to LPF! :wave: Second, can you please resize your photos to 800 x 600 as they are too big at present and some of us will have to scroll across to read all the text. Your photo storage provider should have a button for this.

Thirdly, a capacitor doesn't have an anode and a cathode. Some are polarity sensitive but the are positive and negative. If your capacitor is not marked then it is not polarity sensitive and can be installed either way round.

Fourthly, when you say the extra contacts on the diode do you mean the small PCB on the back that is connected to the pins at the moment? If so, there is a video tutorial in the guide in my sig called, "Harvesting the PHR sled". It's near the end but you'll see it. You can either carefully cut the ribbon away as in the video or you can be very quick and desolder it using a blob of solder on the end of your iron and VERY quickly removing the ribbon and plastic board. These diodes do not like a lot of heat and can easily be killed when desoldering this PCB. It may sound counter intuative but use a hot iron for a short time. Most with experience can do this in less than a second.


I would also be careful about the manufacturer's claims on output power from the driver. I've seen similar ones that will fry a diode in an instant because they put out much more than claimed. I would start off with the lowest setting and if that's not very bright, then the next, and so on. I'm guessing you don't have a Dummy Test Load to determine the actual output? Without one you are gambling a little.

I could be wrong here, and prepared to be corrected, but that LD only looks like a PHR-803T diode and those will only be good for ~100mW at 110mA max. What did the kit cost? Do you have a link?

M

 

[Morgan]

:bumpit:Resized perfectly! Top marks!

I hope the rest goes well too...

M

 

[ajengen]

Thanks! That is some great info! The capacitor will go on tonight.

You're right on, I was wondering about the pcb on the diode. While I've read about "harvesting" the diode, I didn't know until now what it actually meant.

The kit cost 44.99 US here-> 405nm 150mw Blue Laser Diode Module Kit Blue-ray violet. I've contacted the seller once before, I am sure he could give me some more info about the components in the kit.

I'd really like to get the best output from this laser (stable and long lasting). While I've examined how drivers are wired together, I've noticed that two resistors are usually used. The driver kit I have comes with a pair of resistors for each power output option, but the kit specifies to solder only 1 resistor to the pcb. :thinking:

Can I ask these kit-specific questions here, or should I being a new thread elsewhere?

Thanks a lot! :beer::beer:

 

[Morgan]

No reason you can't ask kit specific questions here or in another thread. The problem is whether anyone has experience of this particular driver. The best person to ask is the seller. They should be able to verify which resistors meet the required output as they should have built a few lasers using them. From the details given in the posts above you want the 2R7 resistor for 100mW but I would still start lower and work towards that. It will mean soldering and desoldering a couple of resistors but that's better than blowing your diode. If the higher resistors work out, (20mW then 50mW...), then you need to stop at the 100mW one. Any higher and you seriously risk your diode as no PHR LD will output 200mW!

It also worries me that the resistor values are matched with a mW output. This is never going to be accurate as any number of different diodes could be used. They should really be matched to a mA output. You should check with the seller and at least get some sort of agreement should your diode go pop. You should also invest in a Dummy Test Load and digital multimeter, (if you haven't already got one), before hooking your diode up so you can check the actual mA output.

Bearing in mind these drivers are normally just a few bucks and the SMD components just a few cents in bulk; an Aixiz module with lens is somewhere around 5-7 bucks and a PHR diode generally no more than $10, you can see that this kit may be quite profitable for the seller. All that said, you gotta start somewhere, right?!!!

Do you have a link to the sale on eBay?

M

 

[Mohrenberg]

Two layer PCB on the diode, with that little tab. I bet you anything it's a PHR diode... powered at 120mA a phr diode can get you anywhere between 80-120mW depending on the diode itself...
Although my diode knowledge is sooo rusty now since i've moved out of the actual laser part of the laser hobby and stick strictly with chopping up metal....

are those pictures from the seller? It really bugs me how they label the resistors in terms of mW as that's impossible to know, with any diode. Would be better if they would actually tell you what current it's going to output with each resistor.

OOOHH!!! That harvesting video is mine!! lol, I still get tickled when people refer to the phr and LOC harvesting videos.....i think those are the only two things i contributed which have served the forum good.

Also, Welcome to LPF!!

 

[ajengen]

Thanks for the responses!

Here is the listing:
405nm 150mw Blue Laser Diode Module Kit Blue-ray violet - eBay

I sent the seller a few questions about power outputs and tolerances for this kit, hopefully I will hear back soon and share.

If you visit the ebay listing, you can see a table there with info about the laser diode. What is confusing, is that the listing says its 150mW, the diode included is 125mW cw or 250mW pulsed, and the lowest resistor in the kit is for 200mW output. Maybe I'm missing something...

I do have a digital multimeter, but nothing to load the circuit with. What function should my multimeter have? I have this one

Anyway, I'm glad to have something to work with ATM. Once I've figured this kit out, I am probably going to pick up individual components for the next project

 

[Mohrenberg]

Thanks for the responses!

Here is the listing:
405nm 150mw Blue Laser Diode Module Kit Blue-ray violet - eBay

I sent the seller a few questions about power outputs and tolerances for this kit, hopefully I will hear back soon and share.

If you visit the ebay listing, you can see a table there with info about the laser diode. What is confusing, is that the listing says its 150mW, the diode included is 125mW cw or 250mW pulsed, and the lowest resistor in the kit is for 200mW output. Maybe I'm missing something...

I do have a digital multimeter, but nothing to load the circuit with. What function should my multimeter have? I have this one

Anyway, I'm glad to have something to work with ATM. Once I've figured this kit out, I am probably going to pick up individual components for the next project

That DMM should work as it can read mV in the photo.
with the test load your mA will be measured in mV. ie: 1mV = 1mA output.

 

[Morgan]

OOOHH!!! That harvesting video is mine!! lol, I still get tickled when people refer to the phr and LOC harvesting videos.....i think those are the only two things i contributed which have served the forum good.

I think you're selling yourself short Mo!

Those vids are good tutorials though. I hope you don't mind me poaching them and including them in my guide? They are very useful...


@ ajengen - You'll find that many suppliers will over-estimate the output of a diode. Often these figures come from a freak diode or a diode that made it to those levels but only stayed alive for a few minutes, etc. They should be taken with a pinch or two of salt. As you get to know your raw materials you'll understand what you can and can't expect. It's just experience gained. A good thread for diode parameters is here, (not complete anymore as other diodes have come on line but complete to a point...) -

http://laserpointerforums.com/f51/diodes-compilation-all-diodes-data-one-thread-45042.html


Where a diode has a CW and a pulsed output quoted, this information will usually be extracted from the manufacturer's data sheet. The CW figure is how much the manufacturer says the diode can comfortably output and make it to the designed lifetime, (say, 10,000 hours). This also applies to the pulsed output. In normal operation, in the drives they are designed for, the diode will be driven at the pulsed output with a set duty cycle. Commonly, we will drive our diodes at the pulsed output figure but in CW, (Constant Wave), at the expense of lifetime, (this could be as low as 100 hours). This is merely a rule of thumb and may not apply quite like it used to. You can also see from the information in the link above that it seems the data you've been given is likely not from the datasheet of the diode you have!!! (I'm not aware that this diode even has an internal photodiode to monitor current, but I may be wrong.)

The driver you have there is setup to be able to drive other diodes as well so the 200mW setting would not be suitable for the diode you have but for a more powerful one, (if we are to believe the setting is accurate).

Your choice of power source can also have a bearing on the output of these boost drivers so ask the seller what they recommend.

For future builds you may want to have a look for Dr.Lava's Flexdrives or Microboosts and for the RKCSTR driver in either the, "Pro-Shop", or, "Buy, Sell, Trade", sections. They are more expensive than many supplied outside of LPF but they are well understood and well trusted with much better support and backup.

Good luck.

M

 

[ajengen]

Thanks for sharing everyone!

I have been trying to gather more data about this driver kit, and it does appear that the driver may have a higher output capacity than the included diode can handle, although I could be wrong. If anyone has some info on this driver or has a build using these components, I wanna know about it!

I have a feeling I may drop all the components of this kit except the laser diode and heatsink and opt for getting stuff from radio shack. I read the DIY by Daedal, and I think that is where I should have started... oh well!

I was thinking about using a Raytek Minitemp MT6 as a host, has anyone done that yet?