Help needed for first build: module + aluminium housing

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So this is what I have, a 30mW 532nm module rescued and resoldered from a dead driver, and an old infrared flashlight housing. I think it would make a great housing for the module, but i've ran into some problems:

The flashlight case has a switch in the bottom, which to my understanding uses the flashlight body as the negative lead. I've been thinking CR2 or smth as the battery but if I want to use the two-position clicky switch I have to solder the module's own switch shut and wire accordingly?

Also what could I use to mount the module to fill the diameter of the cap?

(Oh and the ruler is a metric one).

Thanks in advance.

EDIT: added a pic of the tailcap switch

The case negative problem is incredibly easy to fix. It's as simple as reversing the battery. Unless the switch has a diode or driver in it, it will work either way. Just solder the switch shut and it'd be good to go. Case positive is also a good idea, as the brass casing of the diode is positive (NOT neutral), and it'd be in contact with a heatsink.

As for the head, you want a machined heatsink that holds the module, and is kept in place in the head.

Yep, just solder a wire across the module's switch to bypass it.

May as well make it host positive like goninan said; it'll be much easier.

Alright, the thing now has a battery holder (20mm PVC tube) and the 30mW module switch has been bypassed and a spring attached.

The brass part of the laser module is going to protrude out of the top of the housing, so I'm having a hard time figuring a way to mount a heatsink in it. I tried steel washer rings but I can't use the grooves on the laser module because they seem to be incompatible with pretty much every nut I can find at local stores.

EDIT: pic of the top part of the assembly (the acrylic disc is only a temporary solution to hold the module in place)



Any ideas?

To be honest with only 30mW it's unlikely that heatsinking will be too much of an issue. I would be happy to run it without one but just keep an eye on the stability and do a, 'touch', test every so often to see if that remains constant too. If the beam is constantly shifting in brightness, etc, then a heatsink may be necessary but not critical at that power IMO. The heat is actually produced at the driver end anyway by the diode so you may be able to sink some of the heat inside the host if you absolutely need to.

An alternative may be to find some 3V CR2 batteries. It's a bit difficult to tell from the photo but your battery looks like a longer one than the CR2. Most of the laser parts suppliers will have these in stock with a charger and are not a huge cost. It would be neater to have the module further in the host .

See how you go...

M