CNC Cyclone PCB Factory: limit switch – Part 3
This feature it’s very important, because with limit switch you can go at “home” and than go to the previous position with rotary tool, and you can mill double side PCB without problem.
Electronic: Mechanical Limit Switch
The printed part expect the limit switch in the photo, and It’s a good choose to prevent part of noise.
Original guide to remove noise.
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In the image grab from shapeoko forum, you can see that noise reduction schema is quite similar to the schema of mechanical switch module, but there is a problem, the capacitor is near switch not near pin.
To prevent my additional noise I add (as you can see in the picture) an additional capacitor 473 near the controller, if you want, you can add It directly to the wire or create an additional service board, you must connect blue (or green) and black wire of the switch.
Mechanical switch is connected from internal to external as GND, SIGNAL, and you must add a service board to give VCC.
As already write I had to create an additional service board to reduce noise near the microcontroller, that simply add a capacitor 473 to the GND and SIGNAL of limit switch (BLUE and BLACK wire), as you can see you can add It directly to the wire.
I’d like to add service board to give VCC also to the limit switch.
As you can see in the photo service board is simple prefored board that have 2x6pin (male-female) and 3x6pin male, with this I add a pin with vcc to switch and “expanded” VCC and GND for all other component.
Homing with limit switch
Video of a noise problem on limit switch
Panic after a noise problem on limit switch.
In the next part I’m going to show my solution for probe helper and relay to power on rotary tool.