Micro laser driver - fits Aixiz/DX modules

[Mr_Bojangles]

Hi, I have pretty much no idea what I'm doing. I can't really find any in-depth instructions or anything (other than the video on the instructable) for doing the KipKay Instructables flashlight hack and installing a driver. What exactly does a driver do? How easy is it to install? Where do I install it? Do I even need it for this laser? I have no experience in this kind of thing, but I figured I might as well start with something like this.

 

[rkcstr]

Just a quick question. I've been thinking of making an MXDL build one of these 38ma drivers. But I don't know what to run it on. I think jayrob said these batteries are good
http://www.dealextreme.com/details.dx/sku.974
But that's for DDL's driver, would 3 of these batteries be too much for this driver?

You should be OK with two of them for my driver. The average output voltage of two is right around the minimum voltage for my driver, but you should be fine. You can just use two in one of those 3x AAA battery holders and either use a dummy battery (anything to short out that extra battery port) or some others have actually just mounted the driver in that extra space.

Hmm... after the 38mA driver zombified my diode, I decided to hook some different resistors to it and see how far I could push it....

Before I removed the 33r0, I did a quick check with my multimeter, and it seems the old resistor was only providing 1.8 ohms resistance... (this was in-circuit, I haven't checked it by itself yet, it's in the bottom of my sponge I guess).. I shrugged that off and soldered in a 25r5 (or whatever the next lower resistor is, I'm going from memory), powered it on with 4 diodes attached, nothing happened, 0mA. so I checked the resistance of the newly soldered resistor and was dismayed to find it was offering 1.6ohms of resistance. I went around all the traces with an exacto knife to ensure there were no shorts

I suppose something important has been fried, but do you know why the resistors would be doing that?

Well, I doubt it's the resistors. Is this the driver that had the blown trace? It's possible the regulator chip is damaged and shorting the adj/out pins. Also the output cap could be blown and shorting out. I'm not exactly sure of your problem, but if you want to send it back, I could see if I could fix it, or just replace it.

 

[rkcstr]

Hi, I have pretty much no idea what I'm doing. I can't really find any in-depth instructions or anything (other than the video on the instructable) for doing the KipKay Instructables flashlight hack and installing a driver. What exactly does a driver do? How easy is it to install? Where do I install it? Do I even need it for this laser? I have no experience in this kind of thing, but I figured I might as well start with something like this.

Well, from what I understand, the Kipkay thing is a very uninformed and irresponsible method of making a laser. With laser diodes, they don't just need a particular voltage, they work best with a regulated CURRENT (it's a good idea to look up voltage, current, resistance all part of Ohm's Law). Merely adding a resistor in series with a diode will not be adequate for long term use and dependability.

The drivers I make are a specific current-regulating circuit that is meant for driving laser diodes. As for ease of installation, have you ever used a soldering iron? If not, it may not be a good idea to make this your first attempt. In terms of soldering, this is relatively simple, though. They are meant to be directly soldered to the laser diode, but it is not necessary.

I highly recommend a current-regulating driver for your laser diode rather than just a resistor and/or capacitor.

 

[Mr_Bojangles]

So is there like a full kit or anything that you'd suggest for my first laser project? I'm interested in learning stuff about them, and I also don't want to pay $200 for a name-brand laser that I could get for a lot cheaper.

 

[pseudolobster]

Well, I doubt it's the resistors. Is this the driver that had the blown trace? It's possible the regulator chip is damaged and shorting the adj/out pins. Also the output cap could be blown and shorting out. I'm not exactly sure of your problem, but if you want to send it back, I could see if I could fix it, or just replace it.

Yes, it's the driver a trace blew on. Nah, it's okay... I'll just give up on it... just curious why it might be doing that. You were right about the resistors though, I desoldered the one I put on there and it's measuring 25ohm now.

So is there like a full kit or anything that you'd suggest for my first laser project? I'm interested in learning stuff about them, and I also don't want to pay $200 for a name-brand laser that I could get for a lot cheaper.

That's a pretty broad question to ask in the middle of a discussion about a specific driver... you might want to create your own thread... or not, really, this has been covered hundreds of times already.. You'll need a dvd burner, this driver, an aixiz module, a battery, and a box to put it all in. Do a bit of reading before you dive in. This thread is a good place to start.

 

[rkcstr]

Yes, it's the driver a trace blew on. Nah, it's okay... I'll just give up on it... just curious why it might be doing that. You were right about the resistors though, I desoldered the one I put on there and it's measuring 25ohm now.

The amount of current required to blow a trace is pretty high, so I'm not surprised there are other casualties.

So is there like a full kit or anything that you'd suggest for my first laser project? I'm interested in learning stuff about them, and I also don't want to pay $200 for a name-brand laser that I could get for a lot cheaper.

I'd suggest you do some reading. Take a look around the forum and read about what other people have done and get an idea of what kind of projects you can do. This is certainly something you don't just jump into, otherwise you'll be spending lots of money for blown diodes.

 

[Abray]

Just a couple questions about this...
If I bought one of these for a PHR-803T blu-ray diode, would I be able to just use a 9v battery? Or is it better to try and stay as close as you can to 7.25?

Also, the options only go up to 400mA, but somewhere I could have sworn it said you used the driver at 420 mA? That would help with a particular long open can that works well at 420 mA. If it can't go that high, its fine, I'll still need this driver for blu-rays lol!

Lastly, the tests you did based on heat were all without heatsinking? (besides AixiZ module)

 

[styropyro]

Just a couple questions about this...
If I bought one of these for a PHR-803T blu-ray diode, would I be able to just use a 9v battery? Or is it better to try and stay as close as you can to 7.25?

I can answer the first question for you. A 9v battery will work fine for this, although the more voltage you put in, it the more heat will be generated by the driver. You should be fine with 9v though

 

[rkcstr]

Just a couple questions about this...
If I bought one of these for a PHR-803T blu-ray diode, would I be able to just use a 9v battery? Or is it better to try and stay as close as you can to 7.25?

Also, the options only go up to 400mA, but somewhere I could have sworn it said you used the driver at 420 mA? That would help with a particular long open can that works well at 420 mA. If it can't go that high, its fine, I'll still need this driver for blu-rays lol!

Lastly, the tests you did based on heat were all without heatsinking? (besides AixiZ module)

A 9V battery will work, but it will be dissipating about 0.4W. Comparatively, a 400mA driver will dissipate about 1.75W when inputting ~7.4V for a red diode. Keeping the input voltage close to the dropout voltage will minimize the amount of heat generated. I think you'll be OK on 9V, but you can just test it out at that voltage to see how much it heats up with time.

My fixed-value settings go up to 400mA, limited by the resistor values I have. My adjustable drivers go up to 430-470mA peak. Or, if you can come up with some combination of 4 of these resistor values in parallel, I can do it: 8.2, 12.4, 25.5, 33, 75.

The tests I did were on the drivers as they're made (no heatsink, open to air) with 2x CR2 3.0V rechargeable batteries, with a total voltage of about 6.2-6.5V. I ran the adjustable drivers for over 20min. with no problems at about 420mA. The fixed-value drivers have higher amount of power handling for the resistors compared to the adjustable drivers, so they should be just as durable, if not more. Of course, heat may damage a diode even if the driver is not damages, which is mainly why I don't suggest running for long periods of time at high current.

 

[Abray]

So as long as I buy an adjustable driver (which I was actually planning on doing) then it should be able to go up to 420, awesome!

And 20 minutes is definitely longer than I'll ever need it for! good job on these! I'll be buying some soon (when I get some cash, not that i need much!)

 

[rkcstr]

So as long as I buy an adjustable driver (which I was actually planning on doing) then it should be able to go up to 420, awesome!

And 20 minutes is definitely longer than I'll ever need it for! good job on these! I'll be buying some soon (when I get some cash, not that i need much!)

Well, like I said, if you want a fixed-value driver, just come up with some combination of the resistor values I gave above to make a low enough resistance.  I'm sure you can come up with something at least near 420mA, or you can simply just buy the adjustable driver

Also, if you plan to use with a red burner diode, I suggest the "high" range as it will have slightly finer resolution for adjusting.  The full-range driver gets tough to adjust from about 100-450, as it's the last 10% of the pot's adjustment.  But, that's the sacrifice that needs to be made in order to get such a large range.

Ideally, the high range would be done with a 10 ohm pot (versus the 100ohm I use) which would give much better control over adjustment over a range of about 160-460mA.  Then the low range would better with a 50ohm pot.  Full range may also improve with a 50 ohm pot and higher parallel resistance.

These considerations may be an improvement for the future, but they work just fine as they are now, so I think people will be happy with them.

 

[Abray]

And remember, you are also selling those dummy loads, which makes it a whole lot easier to get the current to the correct setting without the fear of killing a diode!

edit: also, on your payment page, how do we choose whether we want a test load that simulates a red diode or a blu-ray diode?

 

[rkcstr]

And remember, you are also selling those dummy loads, which makes it a whole lot easier to get the current to the correct setting without the fear of killing a diode!

edit: also, on your payment page, how do we choose whether we want a test load that simulates a red diode or a blu-ray diode?

Yes, I highly recommend using a test load (even if it's one YOU made and not mine) to set your current, because there's potential to damage your diode with a "wrong turn" of the pot!

You don't need to select either range because it can do both. It's just set by soldering two pads together on the board. They come preset to "RED", which if you're just setting the current, you don't need to bother setting it to "BLU" for a 405nm diode. That setting is mostly if you need to do more advanced testing where you need the voltage simulated as well, but my driver (or other current regulating drivers) will put out the same current no matter the voltage, so it's not necessary.

 

[Abray]

Yes, I killed my last blu-ray with a wrong pot turn! Even though it turns out I was using a 1Kohm pot instead of a 100 Ohm pot :-[

But anyways, I just ordered an assembled adjustable driver in the low range, along with a test load!

 

[Cxrazy]

So for a fixed 100mw driver powering an 803t bluray I'd need around 7.5v...

So a MXDL with 2 CR123a's at 3.6v? Whats a good CR123A? Just get them off of DX?

 

[rkcstr]

So for a fixed 100mw driver powering an 803t bluray I'd need around 7.5v...

So a MXDL with 2 CR123a's at 3.6v? Whats a good CR123A? Just get them off of DX?

2x CR123A batteries should be fine. I'd suggest getting protected batteries so you don't over charge or discharge the batteries and damage them.

I have some of these:
http://www.dealextreme.com/details.dx/sku.3273

And this charger (though there are cheaper ones):
http://www.dealextreme.com/details.dx/sku.1236