I’m looking into making a MPCNC laser engraver on a budget and am a bit confused on my options for a laser. There seems to be two options, either with or without a TTL driver.
I’ve heard you can get one without a TTL driver and plug it right into your fan port, from http://nathan.vertile.com/blog/2017/12/01/mostly-printed-cnc/
Or with a TTL driver remapped to a 5V port on the board, as explained in the tutorial on this site https://www.v1engineering.com/wp-content/uploads/2016/01/MPCNC-laser-add-on-walk-through-Rev2.0.pdf
So is the TTL driver necessary? It seems lots easier to not have to mess with it. And if it’s not necessary, what’s the benefit of using it?
I am no expert but without ttl I am pretty sure you only get on or off, and I have never ran my laser at 100% power. I think you would lose a ton of functionality without power control.
Interested to hear what other say.
I agree with Ryan. In the linked article, they are using the fan port to get a PWM signal, which is then almost certainly connected to the TTL input on their laser driver. I don’t see it specified in the post, but I suspect that’s what they are doing.
I have a J-Tech laser on my MPCNC, which has a selector switch between TTL and CW (constant wattage). I’ve never used the CW mode - I only ever use TTL.
I suppose it’s theoretically possible to modulate the power of the laser just by turning it on and off really quickly (using a PWM signal), but unless the driver and laser are designed for that and can turn on and off thousands of times per second I don’t think it would behave as expected, and might affect the longevity of both. If it was designed to do that, they’d just call it TTL.
How much cheaper is a laser driver without TTL?
I think the linked article actually doesn’t have TTL. He links to the laser he bought, and from what I saw doesn’t include the TTL driver.
Probably between $10-$15. It’s just extra work to make sure it’s all set up right vs shoving it into the 12V fan pin, but from what I can see/what you all have said it’s probably worth it in the long run.