Dual Optos per axis

HI,

I have a mendel and use repsnapper to get the printbed nice and level.

There are times when I hit the wrong button and the extruder carriage goes flying off and rams into the frame side that doesn't have an opto to stop it.
I'd like to add an opto to this other side to save the pulley grinding out the belt.

I'm using Camiels Gen6 so I don't think I can actually add more optos to the board. However, how could I go about implementing the Max opto? Would I use, for example, some type of arduino board that I takes opto shields and enable the Max opto setting in the firmware?

Has anyone got a link of where this has been done already &/or have ideas about a solution?

cheers

I am surprised that no-one has responded to your post. I think it is a really good idea to have overtravel switches on all the axes.
Maybe if you try posting in the general discussion forum you will have more luck. I will keep a look out for it.

I think most people don't use over travel switches because electrical noise tends to trigger them occasionally by accident.

As a side note, is your pulley actually slipping on the belt? My stepper motors always skip before the pulley loses traction. I have been known to use a gentle 'crash' to home the x and y axis.

The simplest way to prevent a head crash would be to use micro switches on all axis (tied in serial) to the enable leg of the stepper chips. If one of the switches closes, all power to the steppers is cut off. That way, even if the software hangs it still stops the steppers.