adjustable joules by switch

I plan on making a 3 laser 650-660nm 5mW Diffused setup

but I need to up the joules of .5 from 3-4 to 6-7 joules by switch
(switching from 3-4, to 6-7)

This project would be for a LLLT Cold medical laser (For Acupuncture purposes)

I have experience with lasers, but not with joules (or modifying the joules at that)

Any idea of how I could accomplish this?
(having 2 sets of 3 lasers ~one at 3-4, and the other set at 6-7 joules would be fine)

Maybe I understand something wrong because of my crappy english, but as far you mean "joule" like the energy unit joule I think you are missing some physical basics.

There is energy in joules, and there is power in watts. 1 watt is 1 joule per 1 second.

So if your laser has a power of 5mW, this means in 1 second its producing 5mJ of energy per second.

If you need to get 7 joules, your 5mW laser needs to be on for 1400 seconds, but I dont think this is what you are looking for. To get the same energy in 1 second, you need a 7W laser...

-madeye

What is your intended application?

Well its likely my logic is off, so perhaps I would need a 4mW and 7mW set of lasers.

The application would be for 'acupuncture' (Where they normally stick you with needles for healing purposes) They've been using lasers for acupuncture for awhile now, however the laser (as a complete device) can range from 150-2500 in price.

So since its obviously cheaper to make the device myself, I did my research on them. This one guy said that the 'optimal joules range from 3-7' which really threw me off, which is why I came to you guys for assistance.

Ah, I see what it is. You basically need a laser like a need - a quick, SHARP amount of energy. That implies 3-7 J for probably a millisecond or something - where you wouldn't feel it.

There are lasers that can do that... but you won't find them here. They are really expensive and not DIYable.

Ahh, I see, thanks for the info~

Are LLLT/Cold medical lasers on Ebay trust-able?
My father purchased one for around 200 bucks, believes its working (foot pain isn't as intense)

Just curious if the specs aren't as you implied 'sharp and needle like'
Thanks again guys, I found many DIY LLLT lasers and weren't sure if they were effective or not.

I have absolutely no idea. I just assumed that, in the same way that a needle for acupuncture very quickly creates a tiny puncture wound, you would need a laser to do the same, so a quick burn time but lots of energy.

Well I read that its all about 'penetrating' deep enough into the skin to activate the acupuncture points, I assumed it was just the light that needed to get deep enough.

I dont know anything about laser acupuncture, but after short research I learned there are indeed low power lasers in that range used, but it looks like most researches showed its only a placebo...

There is some high powered laser skin therapy, but I could not find out what power this is. But actually if someone is talking about "joules" and lasers, I would think he is talking about pulsed lasers (their power is stated in Joules / seconds) and this would mean this are not be 4-7mW of lasers but 4-7W (But because its pulsed this is only an avarage, the actual power is much higher while the laser is on)

Maybe a well-meant advice from me: As long as you are no laser expert, dont build any medical devices... There is much more science behind everything than you may expect...