I wanted to add air assist to my China k40 type laser machine. I didn't want to buy an air pump, and I didn't want to have my shop air compressor running all the time dumping air out of the nozzle when it was not running/cutting.
So I set out to find a "trigger" on the main board, to enable an air solenoid. The broad I have in my machine is made by Lihuiyu Studio Labs. Its called the M2Nano. I went to their site to find a pinout of the board. But it was all in Chinese. So will a little editing in Illustrator and Google Translator... I figured it out! I have added it here so everyone can see it.
Turns out the that this board, Ver. 7 has a 5DVC trigger output! Now this is my second China laser, the other has a a Ver. 5 M2Nano board, and it DOES NOT have these connections. So your mileage may vary.
I made this with 100% parts I had laying around. So your results may vary.
I had a 5VDC relay. So I thought I would just hook it up directly to the + & - connector on the board. No joy! It didn't have the capability to powering the coil in the relay. I needed to add a NPN transistor to trigger the relay, and use 5VDC from the laser power supply to power the relay.
I went with the 5VDC because the PSU already outputs 5V, so it seems the easiest way.
The relay, in NO mode, is used to switch a separate 12VDC PCU (wall wort) to power the air solenoid. Since there is no 12VDC output on the laser PSU, this was the easiest way.
It works like a champ!! When the laser starts to cut/engrave, the relay is enabled, and air starts to flow. Once the laser is finished cutting/engraving, the board has a 15 second dwell time before the relay is disabled.
This output can be used to do a lot of other things too... turn on water pump, exhaust fans and more. It can be easily configures to switch a 110v device.
Thank for looking. :)