Bought a laser and ttl, but the ttl is reversed 0v/on 5v off. Does any one know how to revers this on the ttl or possible in estlcam (currently using cnc shield with estlcam on mpcnc)
I’m not sure about that one, maybe link the laser you have and someone will chime in on how they made it work.
Fixing it in software seems like the easiest solution, but only if the software supports it. EstlCAM doesn’t do gradients, right? So it would just be setting the ON value to S0 and the OFF value to S255. Code like image2gcode or gcodetools plugin will need to be configured. I haven’t done any of that myself…
If you want a hardware solution, then you can build one quickly with a transistor and a few resistors. Something like this: http://www.instructables.com/id/Logic-Gates-with-NPN-transistors/
There are also Integrated circuits that do the work for you. They will be limited to a certain voltage though, so you have to look at the datasheet. NOT gates are pretty common though, so you can probably find a cheap 8 pin DIP with several of them (and you only have to use one) for very cheap. Something like this guy: https://www.digikey.com/product-detail/en/toshiba-semiconductor-and-storage/TC74ACT14P-F/TC74ACT14P-F-ND/6679245 (although this one is 5V, so if you need 12V, then you need to keep looking or build a transistor circuit).