Stepper & limit switch daughter board

A project log for Upgrade Budget Laser Cutter

I have a laser cutter from China, similar to the K40 (50W 4060) it works out of the box but the software stack and UX needs work.

JoeJoe 04/26/2019 at 11:200 Comments

This daughter board is mounted on the y gantry and provides a connection point for the Y-axis stepper motor and the X & Y-axis limit switches

It connects to the main board with an FFC ribbon cable. After taking a look at Don’s Laser Cutter Things I found out that is is a 12pin 1.25mm pitch FFC cable and ordered a connector from RS Components. I searched for “CONN FFC VERT 12POS 1.25MM”.

After looking at the circuit, I am really confused. I have sketched out the circuit below to make it a bit clearer. If anyone knows what the opp amp is doing, let me know. I will take a look at the controller later to see if I can work out what is happening....