I personally use a 2.8w diode ,likely the same as Jtech does in their set-up but I didn’t buy it from Jtech. If anyone decides to go the DIY route then you’ll want the 2.8w Nichia NDB7875 module from DTR laser shop. This is a well reviewed and documented module among laser enthusiasts and DTR laser shop is also a reputable source in that community. Buy a fully assembled module to save yourself headaches. The NDB7875 module with a G2 lens(same one used by Jtech) is $90 or you can get it with a 3-element lens for $70. Both are good options and from what I’ve read the G2 lens will give you a slightly more powerful beam but a slightly larger spot size so a 3-element lens may be better for detailed work. I use the 3-element lens myself.
You’ll need a 12v TTL driver with output up to 3amps to support that laser module. These can be found on ebay for about $8 . A heatsink can also be found there for another $6 or so. You should be able to connect the laser driver directly to a 12v output on your Ramps board so long as you’re MPCNC power supply has about 10amps or better. The laser should be tuned to run at about 2 amps and that leaves 8 amps left over for the MPCNC stepper motors which is PLENTY for most of our set-ups. The TTL input on the laser driver needs to be coonected to the fan outputs on the Ramps controller so that the M106 and M107 commands will drive it.
I’m pretty busy these days but I WILL make time at some point to do a complete walkthrough for people interested in a laser set-up for under $100.