DIY Homemade laser diode driver

Phew! I read the whole thread through and I've already built two drivers, a regular version with adjustable current and a miniatyre with fixed current, that'll fit inside an aixiz-module. They both work nicely, so thanks for the schematics and everything

The miniatyrization reguired some sanding down of the LM317 so that it will fit inside the aixiz. I also used a 1w smd-resistor and a very small 10uF 16volt capacitor which I found from a disassembled dvd-drive.

Enthusiast forums are always very enjoyable and I hope that I'll be able to contribute in the future.

Well done for getting it exactly right , you decided on the build you wanted, you fully researched it, you built it and all without having to ask dozens of already answered questions.

I dont do this often... and to a first time poster +1

Have fun on the forum you have lots still to make

Regards rog8811

Jaaju said:

Phew! I read the whole thread through and I've already built two drivers, a regular version with adjustable current and a miniatyre with fixed current, that'll fit inside an aixiz-module. They both work nicely, so thanks for the schematics and everything

The miniatyrization reguired some sanding down of the LM317 so that it will fit inside the aixiz. I also used a 1w smd-resistor and a very small 10uF 16volt capacitor which I found from a disassembled dvd-drive.

Enthusiast forums are always very enjoyable and I hope that I'll be able to contribute in the future.

Click to expand...

welcome to the forum, and for the contribution you could take some pictures of your build and put them up here :

since you can't post links here till you got 10 posts i would be happy to post them here for you if you want (not completely unselfish here )

kendon said:

welcome to the forum, and for the contribution you could take some pictures of your build and put them up here  :

since you can't post links here till you got 10 posts i would be happy to post them here for you if you want (not completely unselfish here   )

Click to expand...

Thanks for the kind words rog8811 and for kendon, some pictures. Hope you can see them, I am a bit rusty in posting to forums..

It is not the prettiest build, my first attempt at smd-soldering and keeping everything as small as possible, but it works. The dust on the capacitor is from the regulator which I had to sand down a bit more after I had soldered everything together.  : I added some electrical tape for insulation before putting it in the module. Perhaps I'll try this with a LM317H next, for a red burner, this was for a blu-ray LD. There might be some problems with resistor values, perhaps I'll try two 12 ohms in parallel if they'll fit..

I have seen many builds that look bad, this is not one of them, that is very tidy.
Have you got a host in mind or is this going to end up being a labby?

Regards rog8811

rog8811 said:

I have seen many builds that look bad, this is not one of them, that is very tidy.
Have you got a host in mind or is this going to end up being a labby?

Regards rog8811

Click to expand...

I am doing research about the host, it seems that I must use at least three batteries to power this thing, because of the phr803t-sled LD. 6volts(2xcr123) is not enough and 2x3,6 (rechargeable lithiums) might work when the batteries are full, but for how long? Perhaps a host intended for 3xaaa and 3x10440 lithiums or something similar. A "9v" rechargeable 8,4V battery might be suitable as well if it fits into the host.

Has anyone disassembled these rechargeable 8,4 volt batteries to see if it consists of "button" type cells or "aaaa"-type cells? I've disassembled regular 9v batteries and found both types.

2x3,6 (rechargeable lithiums) might work when the batteries are full, but for how long? Perhaps a host intended for 3xaaa and 3x10440 lithiums or something similar.

Click to expand...

I have done it both ways, 2 batteries do need charging quite frequently, 3 is ideal.

Regards rog8811

Or I could stick to the miniatyre size in everything and use 3 rechargeable button-type cells, like these: tinyurl .com / ar4ev6, the bigger ones seem to be suitable for >100mA currents, or is it just the maximum pulse current, which will sag quickly?

I have only tried button cells once with little success but I have seen others use them.
The batteries I have used in my flip top lighter are GP10A's, 9v 38ma/h, 21mm long and 10mm diameter, 3 of them paralleled up seems to work very well.

Regards rog8811

Hey Rog, I'll bet 3 X 100mAh 10220 batteries will work in parallel for a FlexDrive set up then! They are 10mm X 22mm 3.6 volt rechargeable's. That would give considerably more capacity!
Jay

Jaaju, I ditto everything Rog said. You have done an awesome job.. Congratulations..

Gazoo said:

Jaaju, I ditto everything Rog said. You have done an awesome job.. Congratulations..

Click to expand...

Thanks Gazoo, here is another version with LM317H, which has a maximum current of 500mA. This will fit inside an aixiz module even better. The current is fixed again, with two 22,1ohm 0603 resistors in parallel. The clerk at the store where i bought the components said that the power rating for the resistors is 1/4w, but when I checked some datasheets for 0603 resistors, the ratings were 0,1-0,125 watts, oh well.. But LPF is all about pushing the components to the limits, right? (at least the LD:s)

It is noteworthy though, that should the resistors fail, the voltage will rise.. Perhaps I should consider using 4 0603 resistors in parallel. 'Till then, I'll wait for another tinkering inspiration.

The picture below should show you how to build one for yourself. There seems to be a solder blob in the wrong place in the third picture, between the minus and the center rail, do not short the minus and center rails, unless you want to see the magical blue smoke that makes electronics work.. This blob was removed prior to soldering the capacitor.

That is some nice fancy SMD soldering.... [smiley=thumbsup.gif]

We use the same vero-board in the shop for prototyping
and testing new circuit designs before producing PCBs..

Jerry

Ive set my board up and was wondering.

I got a AC/DC Adaptor. with max output on 7.5V ~2amp max (wont run that ofc) but using that instead of batteries ... safly do it or hold on to batteries?

got a heat sink for the diode and actually fans on the "box" where the board is to keep things cool.

Batteries for portability... and AC adapter for bench testing...

BTW... those adapters (if not the Regulated type)... will give you
a slightly different DC voltage when it has a load as compared to
without a load...

Jerry

ok so there ive been looking around now and there seems to be none stores or radio fix shops alike anymore that is around closeby where i live so i got to order on the intarwebs it seems and I really dont want to order from the USA (long wiat lots of shipping and hurray customs) so i turned to good old Elfa.se (they got absolutly everything )

now of course lots of different things im alittle confused.

Capasitor:
Cap. 0,47uF/50VDC MKT

Diode:
1N4001 diode 1A 50V DO41

LM317:
LM317AT Pos adjustable V-regulator TO220

pot:
Wirewound pot 100ohm 1W

resistor:
Res. 390ohm 5% 3W

silicone diode its probably there but i coulden't find it


now ive been driving around town all day, searching on the internett making myself pretty blind. please do kill me if you find it "lack of search" but i just got to ask before my head explodes the things ive mentioned above are the ones i found most similar if not same as the ones listed in the "you'll need' place.