Opto bed level with mechanical endstop as well?

I want to add an opto 'bed level' unit to my Prusa i3, RAMPS v1.4 system as I implement this [www.thingiverse.com] - but would like to retain the existing mechanical endstop as a safety because the opto probe will be withdrawn when printing.

I can't find any reference to running both together but am sure I can't be the first to try this! Is it possible? Could anyone direct me to information on how to do it, please?

Thanks.

Richard

Edited 1 time(s). Last edit at 07/12/2015 10:50AM by RGN01.

I'm considering using the optical endstop on the bed leveling via a mechanical endstop (i.e. connecting them in series) to do this.

Appreciate any thoughts or pointers that could help.

Thanks

Richard

I've measured my opto endstop and get about 3.2V open and 5V triggered so am considering a circuit like the below to get the benefit of auto bed leveling and mechanical endstop.

Any thoughts?

Richard

I found that the opto endstop I have didn't work as the 3.2V was too high to be recognised as a low logic level. I removed the LED and now have essentially the full 5V range and it works so I'll start testing the wiring diagram I have shown - the difference being that 3.2V is now 0.14V

Richard

I knocked this circuit up, as well as a simple NPN transistor switch to feed an external LED for visual notification of endstop triggering and - it works just fine!

One step closer to finishing my Thing [www.thingiverse.com]

Richard