The new release of LaserWeb has inspired me to buy a Smoothie 4x for my K40. Where do I order the level-shifter that everyone talks about? Anything else I need to get while I wait for that board to arrive?
You can get the level shifter from SparkFun. https://www.sparkfun.com/products/11771
You may also need a Middleman board (if your K40 has the ribbon connector for the X-stepper). Unless you want to rewire all of that.
Alternatively, if you’re not as electronically inclined as some here (like myself), @Scott_Marshall is soon to be shipping his ACR kits (plug & play for the smoothie to K40). They basically have everything needed to plug in your K40 electronics into the ACR & bridge to the Smoothie.
+1 on Scott’s kit - one stop shopping and ready to install. Even some if us tinkerers are looking forward to it because it saves a lot of time ordering parts from different places, having them shipped from all over the globe and then piecing it all together. 
Time is money but the ACR will also reduce frustration which is pricelezz:clap:
Also @raykholo has a solution available
You could get and azteeg x5 mini and mini Viki 2 lCD for about the same price but in a much smaller form package toninstall
You don’t need a level shifter, smoothie supports “open-drain” pin configuration, which means the pin is 5V already ( just inverted ). Level shifter makes it a tad less confusing if you don’t understand how open-drain works, but it’s not required.
@Arthur_Wolf is this the same as just connecting the fire cable to the 2.4 pin?
@Ariel_Yahni_UniKpty A good explanation of open-drain is the external driver example : http://smoothieware.org/general-appendixes#external-drivers
So @Arthur_Wolf that means laser fire to ground pin on pwm connector?
@Ariel_Yahni_UniKpty something like that, I’ve never tried it, and laser psus confuse the hell out of me, i’d have to look at a manual for one again.
@Arthur_Wolf the reason I ask it’s because that the way I have it. Different I don’t have an original smoothieboard 
@raykholo @Alex_Krause Read Link above from arthur
I’ll try it without the level shifter then. My smoothie shipped today, excited. I got the smoothie because I believe in supporting hardworking developers rather than Chinese pirates. How does the azteeg fit in, is it a Chinese clone, or is it its own thing?
@Corey_Renner Azteeg is from a company called Panucatt manufacturer of smoothie compatible board and its located in california and owned by @Roy_Cortes