On the little adapter board photo (the one without the digital readout) I show a few posts back – if you choose to use it – it gives you 3 different ways to connect your Neje laser module to your PWM controller and laser power.
-
Notice the screw terminals at one end. They show TWO wires to the center GND terminal where the GND “sharing” would occur if wired discreetly, when using separate power supplies for your controller board and laser.
-
A second connection scheme using the 2-wire connector and the barrel-jack… it connects the GND in the 2-wire PWM connection from your controller and the barrel-jack GND from the laser power supply with the adapter board’s plane/trace wiring.
-
The 3-wire connector might be used if you’re using a single power supply to power both your controller and the laser. It implies the GND-sharing is taking place in your controller and all the laser’s required power is coming through those tiny pins in the 3-wire connector. This is probably “sketchy” at best and IMO not the best connection scheme to use.
That little board with the digital readout is SUPER HANDY for testing your Neje laser before connecting it to your machine. Just plug in +12V power brick and the laser module and use the little board’s PWM circuitry to turn on and test the laser to find where the factory focus is set. You can then cut a gauge block to quickly set focus distance to the material surface… like this
– David