Collision Limit Switches

Other Hardware Sensors
1

Hi, I am building a small CNC machine, the bulk of the electronics sorted, I am using a breakout board to connect to motor drivers but I want to use Arduino Collision sensors and would like to connect 2 limit switches on each Axis,i.e 6 in all, I know if I was using Micro switches I would connect in series but collision switches have a 5volt supply so not sure if I may have to run each one through a relay block, can anyone advise best way to connect, cant find anything on internet was also thinking of using another Arduino with the limit switches to give me a fault output for each axis XYZ to stop CNC, but again not sure how would connect and program.

Would be most grateful for any help or advise.

Regards John

2

A data sheet on your switches is needed to determine what the output signal is like

3

There's two common purposes for limit switches:

  1. As a position indicator, so you can zero the steppers to a known home position.

  2. As a safety device to reduce the severity of a crash.

#1 is just logic input to the controller. #2 might cut power to the motors or controller.

4

What I have is the Arduino Collision Limit switches, small board with Micro switch and LED couple of resistors and a 3 pin VCC, GND and Output, I tried breadboarding to light LED 30ma drain from the LED pulls the output pin down to 3 volts and when actuating obviously goes to 0v, So not very happy connecting 2 output pins together so I think I will use the Arduino 8 way Relay module, I already have one.
I am using has a safety device i.e 2 on each axis feeding to the breakout board X, Y or Z inputs.

Another off the cuff problem I have built a UV Exposure Unit using an Arduino Nano as the timer for the UV LED strip lights, works fine but every few times of use it seems to clear the Sketch so I have to reload, I was wondering if it could be transients from the small relays even though they have 1n4001 diodes across them, I use 3 relays so I can switch from Top, Bottom or both UV LEDs ON, the output to the LEDs is via a IRF510 and the relays are switched via a 12volt line, which also feeds the Nano board this board has a 7805 to give me 5volts for the nano

Regards John

5

Why dont't you just use normal endstops like for example

put all outputy paralell to one interrupt pin of the arduino, and use the interrupt function to determine which endstop is pressed. Don't forget to "software-debounce" the endstops! If this could satisfy you setup, and you don't know how to program it, let me know, i have some code for a 2d stage using nema 8 motors....

6

Thanks for the comments, I think I just like to make things complicated as I got these Limit modules and the Relay board already, being retired I like to try the hard way LOL, I originally started using the design with a Uno board but it then progressed to Mach3 using parallel output to drive a Breakout board etc etc.

Main use of this project is for PCB drilling using Eagle design to G-code I want to also program from a Webam mounted in place of spindle but finding very difficult to find info on XY positions programming.

John