DDL style driver in MXDL?

i heard alot of people talking about using DDL's driver inside MXDL hosts, but i can't seem to find a guide on how to fit it all in... did someone have a group buy on PCBs that would fit inside the MXDL? or do you have do it yourself?

Here's the thread. In this build DDL used the TO-92 package which is a samll LM317 but it can only handle up to 100mA, you can still use the normal TO-220 LM317 which can handle up to 1.2 A, DDL only used the smaller one so he could fit everything more easily, but like I said, you can use the big one. Just ask jayrob, all the MXDL lases he's build have used TO-220 sized LM317s. (although he cut their heatsinks so they could fit inside the MXDL)

r34p3rex said:

i heard alot of people talking about using DDL's driver inside MXDL hosts, but i can't seem to find a guide on how to fit it all in... did someone have a group buy on PCBs that would fit inside the MXDL? or do you have do it yourself?

Click to expand...

With your heatsink (which is mailing out tomorrow), I included the 'hard copies' of these two documents:
http://www.sonic.net/~jayrob/MXDLDriverTips.doc
http://www.sonic.net/~jayrob/MXDLHeatsinkTips.doc
There are some good tips in there for you.

My build is just a 'pumped up' version of DDL's original 'DIY Laser Torch' that chido linked above.

The differences are:
* The open can diode.
* The 3 ohm resistor instead of the two 10 ohm resistors. No pot needed for the MXDL build. (I put a 3 ohm resistor in the package)
* The heatsink.
* At this current, you want to use the 3.6 volt batteries.
Jay

chido said:

(although he cut their heatsinks so they could fit inside the MXDL)

Click to expand...

The heat sink of the LM317T does not have to be cut to fit in MXDL. I feel that it was design with it for a reason. Here is a link with a picture of mine.

http://www.laserpointerforums.com/forums/YaBB.pl?num=1206911062/15

thanks guys

hydro said:

The heat sink of the LM317T does not have to be cut to fit in MXDL. I feel that it was design with it for a reason. Here is a link with a picture of mine.

http://www.laserpointerforums.com/forums/YaBB.pl?num=1206911062/15

Click to expand...

Good point, I never knew you could fit the entire LM317 in there. I wonder why jay cuts the heatsinks then. :

I'm not sure why either. My Dorcy Metal Gear is the same way also with the whole LM317T. I'm sure it function 100% to spec with the heat sink and I think it look like a production built rather than a modify DIY built.

chido said:

[quote author=hydro link=1208741930/0#3 date=1208760768]The heat sink of the LM317T does not have to be cut to fit in MXDL.  I feel that it was design with it for a reason.  Here is a link with a picture of mine.  

http://www.laserpointerforums.com/forums/YaBB.pl?num=1206911062/15

Click to expand...

Good point, I never knew you could fit the entire LM317 in there. I wonder why jay cuts the heatsinks then. :
[/quote]

I have found that it is necessary to cut the LM317 heatsink for it to fit. (which does not hurt it in any way at this current/voltage) The aluminum threaded driver mount from the MXDL screws down into the barrel and 'stops'. It is important for this to be 'tight'. The negative current travels through the threads. hydro may have cut this 'stop ring' off, allowing it to screw down farther into the barrel. (which would give more room up top)

If a guy were to cut the top off of the aluminum piece, I would recommend using a little thermal compound. Because it will be 'loose'.

Gluing it in place with thermal adhesive would not be a good idea either, because you may want to take it apart one day. Even if it is just to change the resistor/current...
Jay