Arduino CNC Shield Power Routing

[Desertboy]

BTW, on the subject of Arduino power - I'm pretty sure that the Uno spec says that it is happy with 7-12V as it has onboard regulation to give 5V for the Atmega chip, etc. I think my Sanguinololu 3D printer controller (that dates me...) uses 12V. I'm in the process of developing an Arduino-based controller for a different kind of machine at the moment, which is why I was looking this up on the Arduino site a couple of nights ago. It may be that the shield does not pass its power to the Arduino purely because its acceptable input voltage range exceeds what is acceptable by the Arduino.

Not sure the specs but you cannot use 12v inductive sensors on a ramps board directly you need to wire some resistors to drop the voltage as it will fry the arduino so I would err on the side of caution.

[Neale]

Not sure the specs but you cannot use 12v inductive sensors on a ramps board directly you need to wire some resistors to drop the voltage as it will fry the arduino so I would err on the side of caution.

I can believe that - most of the motion control boards have the same limitation. The basic electronics is 5V and won't handle more than that on any digital input. With the Arduino, the digital input pins go direct to the Atmega chip and that is rated at 5V on all inputs. However, the power supply via the Vin pin should be happy with 12V as this goes to a voltage regulator to give 5V for the rest of the board. In fact, if you are not supplying 5V via the USB connector, the recommendation is to run the Arduino on at least 7V as the regulator needs a bit of headroom to work correctly.